High-performance near-pure zinc alloy, preparation method therefor and use thereof

Abstract

A high-performance near-pure zinc alloy, a preparation method therefor and a use thereof, relating to the technical field of zinc alloys. The alloy component is that the content of Zn is greater than or equal to 99.5%, and the remaining trace alloy elements include at least two of the following 14 elements: Mg, Mn, Li, Cu, Ag, Ca, Sr, Fe, Zr, Ti, Al, C, Ga, and Si. The alloy has the yield strength ≥ 250 MPa, the tensile strength ≥ 320 MPa, the elongation ≥ 25%, the mechanical property change during one year of room-temperature storage ≤ 5%, the maximum bending force ≥ 2 kN, the stress corrosion sensitivity factor ≤ 15%, the size of corrosion pits after 60 days of immersion ≤ 15 μm, and the standard deviation of the size of corrosion pits ≤ 3 μm. The alloy is suitable for the preparation of biodegradable stents, bone implant devices, medical staplers or anastomotic nails for intestines, blood vessels or nerves, vascular clamps, guided bone or tissue regeneration membranes, heart valve protheses, dura mater repair membranes, soluble bridge plugs and fracturing balls for oil drilling, zinc alloy die castings, electroplated zinc materials, building zinc materials, battery-grade zinc, printing-grade zinc, and zinc-based brazing alloys.

Description

High-performance near-pure zinc alloy and preparation method and application thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of zinc alloy, and relates to a high-performance near-pure zinc alloy and a preparation method and application thereof. BACKGROUND

[0002] Zinc is one of the essential trace elements for human body, and has the effects of promoting bone cell proliferation and differentiation, anti-inflammation and anti-thrombosis. Zinc has a suitable degradation rate, meets the requirements of the field of orthopedics and coronary implant devices, and can gradually degrade after playing a function, thereby avoiding the long-term risk of secondary surgery removal or implantation in the body caused by traditional materials. Therefore, zinc is a potential new generation of medical degradable metal material.

[0003] With the development of medical devices such as bone nails, coronary stents and the like towards light weight and high biological adaptability, higher requirements are put forward for the strength, plasticity and stress corrosion resistance of the material. The mechanical properties of pure zinc are poor, and the strength is less than 100 MPa, which is far from meeting the requirements of degradable metal implant medical devices. Alloying is one of the effective methods to improve the strength of pure zinc, and the current strategy is to improve the strength by increasing the addition amount of alloying elements. For example, Tong et al. reported that the total amount of alloying elements in Zn-4.5Ge alloy was 4.5 at.%, and the tensile strength was 237 MPa (X Tong, et al. Acta Biomaterialia, 2018, 82: 197-204.). E. Mostaed et al. reported that the total amount of alloying elements in Zn-2.5Ag-0.6Mn alloy was 3.1 at.%, and the tensile strength was 302 MPa and the elongation was 35% (E Mostaed, et al. Acta Biomaterialia, 2020, 105: 319-335.). With the continuous improvement of alloying degree, the performance is slowly improved, and the resource dependence and raw material cost of the material are continuously improved. For example, Tang et al. reported that the tensile strength of Zn-3.1 at.% Cu alloy was 257 MPa, and the elongation was 47%. When 2.6 at.% Mg was added, the tensile strength was increased to 440 MPa, but the elongation was only 1%, and the total amount of alloying elements was 5.7 at.% (Z B Tang, et al. Materials and Design, 2017, 117: 84-94.).

[0004] Following the existing design idea, it is feasible to increase the strength of zinc alloy by increasing the addition amount of alloying elements, but the device made of highly alloyed zinc alloy is easy to cause the following problems after being implanted into the human body:

[0005] (1) A large number of alloying elements are released into the surrounding tissue, which may cause side effects if the metabolism is not timely;

[0006] (2) The alloying elements form intermetallic compound second phases with Zn, and the volume fraction of these second phases increases with the content of alloying elements. Most of these second phases have a longer degradation period than the Zn matrix, which may cause long-term retention of degradation products in the body. On the other hand, these second phases form a microgalvanic couple with the Zn matrix, accelerating the localized corrosion of the zinc alloy. A large amount of corrosion products cause the aggregation of inflammatory cells and macrophages, which cannot be cleared in a short time and reach a steady state, resulting in poor biocompatibility.

[0007] (3) Highly alloyed zinc alloys are prone to localized corrosion due to the presence of a large number of second phases. In a stress corrosion environment, the stress field between the second phase and the Zn matrix leads to stress concentration and crack initiation, exacerbating localized corrosion and becoming a key reason for the premature failure of the device during service. Bowen et al. implanted Zn-xAl (x = 2.4, 7, 11.3 at.%) alloys into the aortas of rats, and three months after implantation, acute local inflammation with neutrophil and eosinophil infiltration was still observed. The higher the Al element addition, the more obvious the inflammation. Zn-Al alloys exhibit intergranular corrosion during service in the aorta, which easily leads to implant rupture and failure. High-dose Al elements are not metabolized in time and are prone to cause neurotoxicity (P K. Bowen, et al. Journal of Biomedical Materials Research, 2018, 106:245-258.).

[0008] Therefore, how to break the limitations of existing design ideas and develop a medical degradable zinc alloy with high strength, high plasticity, stress corrosion resistance, excellent biocompatibility, and uniform degradation while minimizing the addition of alloying elements is a key problem that needs to be solved. SUMMARY

[0009] The national standard GB / T 470-2008 "Zinc ingot" divides zinc ingots into five grades according to chemical composition, namely Zn99.995, Zn99.99, Zn99.95, Zn99.5, and Zn98.5, with purities of 99.995%, 99.99%, 99.95%, 99.5%, and 98.5%, respectively. The present invention addresses the problems of high alloying element content (high number of intermetallic compound second phase particles), slow performance improvement, stress corrosion cracking, and poor biocompatibility of existing zinc alloys. A high-performance near-pure zinc alloy and its preparation method and application are provided, which still has high performance while ensuring high purity of zinc (volume fraction of second phase particles ≤2%). The "near-pure zinc alloy" has the following three characteristics:

[0010] (1) the components are in atomic percentage (%), the content of Zn is greater than or equal to 99.5%, and the rest is artificially added trace alloying elements;

[0011] (2) the yield strength is greater than or equal to 250 MPa, the tensile strength is greater than or equal to 320 MPa, the elongation is greater than or equal to 25%, the mechanical property change within 1 year of room temperature storage is less than or equal to 5%, the maximum bending force is greater than or equal to 2 kN, and the stress corrosion sensitivity factor is less than or equal to 15%;

[0012] (3) the degradation uniformity is high, the corrosion pit size (i.e. equivalent diameter) is less than or equal to 15 μm after immersion for 60 days, the standard deviation is less than or equal to 3 μm, and the uniformity coefficient of the corrosion pit distribution is greater than or equal to 80%. The calculation formula of the uniformity coefficient η is as follows:

[0013] wherein, p i is the number of corrosion pits in the i-th grid, is the average number of corrosion pits, and N is the number of grids.

[0014] The present application is realized by the following technical solutions:

[0015] The first aspect of the present application is to provide a high-performance "near-pure zinc alloy",

[0016] characterized in that the components are in atomic percentage (%), the content of Zn is greater than or equal to 99.5%, and the rest is artificially added trace alloying elements, including at least two of the following 14 elements: Mg, Mn, Li, Cu, Ag, Ca, Sr, Fe, Zr, Ti, Al, C, Ga, and Si.

[0017] The volume fraction of the second phase particles in the near-pure zinc alloy is less than or equal to 2%, and the size (i.e. equivalent diameter) of the second phase particles is less than or equal to 1 μm.

[0018] By controlling the amount of element addition and combining with the large plastic deformation + rapid cooling process, a co-segregation structure formed by two or more than two elements of the above-mentioned 14 elements is constructed at the defects of grain boundaries, sub-grain boundaries, twin boundaries, and dislocations, without forming other phases.

[0019] The total amount of alloying elements in the near-pure zinc alloy is less than or equal to 0.5%, which effectively avoids the problems of delayed metabolism of alloying elements, long-term retention of second phases and degradation products, and poor biocompatibility in highly alloyed zinc alloys.

[0020] The co-segregation structure formed by the plurality of trace alloying elements in the near-pure zinc alloy has the following four effects:

[0021] (1) effectively hinders the movement of dislocations and the migration of interfaces, significantly improves the strength of the near-pure zinc alloy, and maintains good mechanical property stability;

[0022] (2) Strengthen the interface, improve the ability to resist stress corrosion and inhibit intergranular cracking;

[0023] (3) Stabilize the interface, change the plastic deformation mode of near-pure zinc alloy from dislocation slip to grain boundary deformation, and significantly improve the plasticity of near-pure zinc alloy;

[0024] (4) Weaken the micro-electric corrosion effect and significantly improve the degradation uniformity.

[0025] The microstructure of the "near-pure zinc alloy" of the present application has the following two characteristics:

[0026] (1) The average size of Zn grains is ≤2 μm, the volume fraction of second phase particles is ≤2%, the size (i.e. equivalent diameter) of second phase particles is ≤1 μm, and the dislocation density is ≤2×10 14 m -2 ;

[0027] (2) After being kept at 37-200℃ in air atmosphere for 5-100h, the average size of Zn grains is ≤10 μm, and the microstructure is stable;

[0028] The recrystallization temperature of the "near-pure zinc alloy" of the present application is ≥80℃, which is significantly higher than that of pure zinc (i.e. 15℃);

[0029] The room temperature tensile properties of the "near-pure zinc alloy" of the present application are: yield strength 250-450 MPa, tensile strength 320-650 MPa, and elongation 25%-185%;

[0030] After being stored in 37℃ air for 1 year, the "near-pure zinc alloy" of the present application has a strength reduction of ≤5% and an elongation reduction of ≤5%;

[0031] The maximum bending force of the "near-pure zinc alloy" of the present application is ≥2 kN;

[0032] The room temperature compression properties of the "near-pure zinc alloy" of the present application are: yield strength 260-510 MPa, and stress at 70% compression deformation 750-980 MPa, i.e. compressive strength ≥750 MPa;

[0033] The degradation mode of the "near-pure zinc alloy" of the present application in 37℃ simulated body fluid (SBF), Hank's, phosphate buffer (PBS), and physiological saline solution is uniform degradation, and after being immersed for 60 days, the corrosion pit size (i.e. equivalent diameter) is ≤15 μm, the standard deviation is ≤3 μm, the grid counting method analysis shows that the uniformity coefficient of corrosion pit distribution is ≥80%, and the degradation rate is 0.02-1.8 mm / year;

[0034] The stress corrosion sensitivity factor of the "near-pure zinc alloy" of the present application is ≤15%;

[0035] The "near-pure zinc alloy" of the present application has a cell survival rate of ≥80% for human aortic smooth muscle cells (HASMC), fibroblasts (human aortic adventitial fibroblasts, HAAF), endothelial cells (human umbilical vein endothelial cells, HUVEC), mouse embryonic osteoblasts (MC3T3-E1), and the like, and an antibacterial property of ≥90% for Escherichia coli and Staphylococcus aureus and the like.

[0036] The second aspect of the present application is to provide a method for preparing the near-pure zinc alloy,

[0037] The method for preparing the near-pure zinc alloy comprises alloy smelting → heat treatment → large plastic deformation → rapid cooling;

[0038] The method of large plastic deformation + rapid cooling can induce the formation of a large number of defects (such as vacancies, grain boundaries, twin boundaries, etc.), and promote the formation of a co-segregation structure of various alloy elements at the defects such as grain boundaries and twin boundaries;

[0039] Preferably,

[0040] The smelting process of the alloy uses the corresponding pure metal of each element in the near-pure zinc alloy as the raw material, wherein the raw material Zn is pure zinc with a purity of greater than 99.99%, and the near-pure zinc alloy ingot is obtained by smelting 3-10 times under vacuum or inert gas protection, which can make the composition more uniform and reduce the formation of casting defects;

[0041] The smelting condition is that the smelting alloy uses an Al2O3 ceramic crucible with a melting point higher than 2000℃, and the principle for selecting the crucible material is to select a ceramic material with a melting point at least 800℃ higher than that of pure zinc, which can avoid chemical contamination of the alloy by the crucible material; the smelting is carried out in two steps, first heating to 480-550℃, holding for 1-3 min, then cooling to 420-460℃, holding for 1-5 min, which can promote the co-segregation of alloy elements at the Zn grain boundaries.

[0042] Electromagnetic stirring is applied during the smelting process to make the melt composition uniform, and the frequency of the electromagnetic stirring is 800-3000HZ; at least one melt covering agent selected from KCl, NaCl, MgCl2, LiCl, and borax is also added during the smelting process;

[0043] The heat treatment is at least one of homogenization heat treatment, solid solution heat treatment, aging heat treatment, and two-stage aging heat treatment,

[0044] Preferably,

[0045] The heat treatment includes but is not limited to the following four ways:

[0046] (1) Homogenization heat treatment;

[0047] (2) solution heat treatment;

[0048] (3) solution heat treatment followed by aging heat treatment;

[0049] (4) solution heat treatment followed by two-stage aging heat treatment;

[0050] Preferably,

[0051] The temperature of the homogenization heat treatment is 200-360℃, and the holding time is 3-10h;

[0052] The temperature of the solution heat treatment is 300-360℃, and the holding time is 8-20h;

[0053] The temperature of the aging heat treatment is 50-180℃, and the holding time is 0.1-12h;

[0054] The temperature of the first-stage aging heat treatment of the two-stage aging heat treatment is 50-80℃, and the holding time is 5min-6h, and the temperature of the second-stage aging heat treatment is 100-150℃, and the holding time is 5min-10h.

[0055] The cooling mode after the heat treatment is any one of air cooling, furnace cooling, water quenching, and oil quenching;

[0056] The large plastic deformation is selected from at least one of groove rolling, rolling, equal channel angular extrusion, high-pressure torsion, and high-speed impact;

[0057] The temperature of the large plastic deformation is -50-320℃, and the holding time before deformation is 15min-3h;

[0058] The single-pass deformation of the large plastic deformation is ≥20%, and the total deformation is ≥98%;

[0059] When the groove rolling is performed, the rolling speed is 0.05-0.6m / s, the single-pass deformation is 20%-28%, and the total deformation is 98%-99%;

[0060] When the rolling is performed, the single-pass rolling deformation is 30%-45%, the rolling speed is 0.5-2.5m / s, and the total deformation is 98%-99.5%;

[0061] When the equal channel angular extrusion is performed, the corresponding extrusion pass is 10-25, the extrusion speed is 1-20mm / s, and the total deformation is 98%-99.7%;

[0062] When the high-pressure torsion is performed, the applied pressure is 0.5-6GPa, the deformation number is 2-6, and the torsion speed is 0.3-2r / min;

[0063] The high-speed impact is at a speed of 10-100 m / s, an impact load of 100-1000 N, an impact angle of 45-60 degrees, and an impact time of 0.1-1 s.

[0064] The rapid cooling method after the large plastic deformation is any one of water bath, oil bath, and liquid nitrogen quenching;

[0065] The third aspect of the present application is to provide the application of the "near-pure zinc alloy",

[0066] The near-pure zinc alloy of the present application is suitable for preparing degradable stents such as heart coronary and other vascular stents, urethral stents, biliary stents, tracheal stents, esophageal stents, intestinal stents, porous bone defect filling stents, and other lumen stents and bone tissue repair stents; can also be used for preparing bone implant devices such as bone nails, bone needles, bone plates, wire anchor nails, screws, bone sleeves, bone connectors, bone plate clamps, etc.; can also be used for preparing intestinal, vascular or nerve anastomosis devices or anastomosis nails, vascular clamps, etc.; can also be used for preparing guided bone regeneration membranes, guided tissue regeneration membranes, artificial heart valves, dural repair membranes, etc.; can also be used for preparing soluble bridge plugs for oil drilling, soluble fracturing balls, etc., zinc alloy die castings such as plate shell parts, wear-resistant and shock-absorbing parts, electroplated zinc materials, building zinc materials, battery zinc materials, printing zinc materials, zinc-based alloy solder, etc.

[0067] The key point of the present application is:

[0068] The plastic deformation amount of the common pure zinc metal plastic deformation process is less than or equal to 85%, and neither large plastic deformation nor rapid cooling is needed, because the large plastic deformation + rapid cooling process has no obvious effect on the performance of the processed pure zinc metal. However, the present application adds trace alloying elements with a total amount of not more than 0.5% to the pure zinc metal, promotes the formation of co-segregation structures of two or more than two elements of Mg, Mn, Li, Cu, Ag, Ca, Sr, Fe, Zr, Ti, Al, C, Ga, Si, which have obvious segregation tendency, at the grain boundary, subgrain boundary, twin boundary, dislocation and other defects, instead of forming intermetallic compound second phase particles, so that the performance of the near-pure zinc alloy of the present application is greatly changed and significantly higher than that of pure zinc. The near-pure zinc alloy provided by the present application has high performance under the condition of extremely low alloying element addition amount: yield strength is greater than or equal to 250 MPa, tensile strength is greater than or equal to 320 MPa, elongation is greater than or equal to 25%, the change range of mechanical properties within 1 year of room temperature storage is less than or equal to 5%, the maximum bending force is greater than or equal to 2 kN, the stress corrosion sensitivity factor is less than or equal to 15%, the uniform degradation, after immersion for 60 days, the corrosion pit size (i.e. equivalent diameter) is less than or equal to 15 μm, the standard deviation is less than or equal to 3 μm, and the uniformity coefficient of the corrosion pit distribution is greater than or equal to 80%; and the co-segregation structure formed by the near-pure zinc alloy of the present application significantly improves the strength of the near-pure zinc alloy and maintains good mechanical property stability; at the same time, the stress corrosion resistance and intergranular cracking inhibition ability are improved; the plastic deformation mode is changed from dislocation slip to grain boundary deformation, the plasticity is improved; the galvanic corrosion effect is weakened, and the uniform degradation is promoted.

[0069] Compared with the prior art, the present application has at least the following characteristics and advantages:

[0070] 1. The total amount of alloying elements in the near-pure zinc alloy of the present application is not more than 0.5%, and the content of Zn element in the alloy still meets the pure zinc purity specified in the national standard GB / T 470-2008, however, the strength and mechanical property stability of the alloy of the present application are significantly higher than those of pure zinc; the near-pure zinc alloy provided by the present application has high performance under the condition of extremely low alloying element addition amount: yield strength is greater than or equal to 250 MPa, tensile strength is greater than or equal to 320 MPa, elongation is greater than or equal to 25%, the change range of mechanical properties within 1 year of room temperature storage is less than or equal to 5%, the maximum bending force is greater than or equal to 2 kN, the stress corrosion sensitivity factor is less than or equal to 15%, the uniform degradation, after immersion for 60 days, the corrosion pit size (i.e. equivalent diameter) is less than or equal to 15 μm, the standard deviation is less than or equal to 3 μm, and the uniformity coefficient of the corrosion pit distribution is greater than or equal to 80%.

[0071] 2. The large plastic deformation + rapid cooling process provided by the present application promotes the formation of co-segregation structures of two or more of Mg, Mn, Li, Cu, Ag, Ca, Sr, Fe, Zr, Ti, Al, C, Ga, Si, which have obvious segregation tendency, at the grain boundaries, sub-grain boundaries, twin boundaries, dislocations and other defects, without forming intermetallic compound second phase particles.

[0072] 3. The co-segregation structure formed by the near-pure zinc alloy of the present application significantly improves the strength of the near-pure zinc alloy and maintains good mechanical property stability; at the same time, it improves the stress corrosion resistance and inhibits intergranular cracking; promotes the plastic deformation mode to change from dislocation slip to grain boundary deformation, thereby improving the plasticity; weakens the galvanic corrosion effect and promotes uniform degradation.

[0073] 4. The total amount of alloying elements in the near-pure zinc alloy of the present application is low, the volume fraction of second phase particles is ≤2%, and the size (i.e. equivalent diameter) of the second phase particles is ≤1 μm, thereby effectively avoiding the problems of delayed metabolism of alloying elements, long-term retention of second phase and degradation products, and poor biocompatibility in highly alloyed zinc alloys.

[0074] 5. The average size of Zn grains in the near-pure zinc alloy of the present application is ≤2 μm, and the dislocation density is ≤2×10 14 m -2 , and the average size of Zn grains is ≤10 μm after being kept at 37-200℃ in air for 5-100 h, thereby having good structure stability; the recrystallization temperature of the near-pure zinc alloy of the present application is ≥80℃, which is significantly higher than the recrystallization temperature of pure zinc (i.e. 15℃).

[0075] 6. The preparation method provided by the present application is easy to realize industrialized batch production. BRIEF DESCRIPTION OF DRAWINGS

[0076] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0077] Fig. 1 is a co-segregation structure diagram of Mn and Mg elements in the grain boundary of the near-pure zinc alloy 2 prepared in Example 2 of the present application (wherein the oval frame represents the co-segregation zone).

[0078] Fig. 2 is a zinc grain structure diagram of the near-pure zinc alloy 5 prepared in Example 5 of the present application.

[0079] Fig. 3 is a tensile mechanical property column chart of the near-pure zinc alloy 2 prepared in Example 2 of the present application.

[0080] Figure 4 is a comparison chart of the maximum bending force of the pure zinc of the embodiment 8 of the present application and the comparative example.

[0081] Figure 5 is a corrosion pit morphology chart of the near-pure zinc alloy 10 prepared in the embodiment 10 of the present application after immersion in the simulated body fluid (SBF) at 37℃ for 60 days, after removing the corrosion products. DETAILED DESCRIPTION

[0082] In order to make the technical problems, technical solutions and advantages to be solved by the present application more clear, the following will be described in detail in combination with the drawings and specific embodiments.

[0083] Test method:

[0084] The recrystallization temperature, room temperature tensile mechanical properties, room temperature bending properties, corrosion rate, biocompatibility and stress corrosion sensitivity of the near-pure zinc alloy were tested.

[0085] Among them, the recrystallization temperature was evaluated by combining metallographic method and hardness method;

[0086] The room temperature tensile mechanical properties were evaluated according to GB / T 228.1-2010 "Metallic Materials - Tensile Testing - Part 1: Method of Test at Room Temperature";

[0087] The room temperature bending properties were evaluated according to GB / T 1449.5-2005 "Metallic Materials - Tensile Testing - Part 5: Method of Test for Flexural Properties of Unnotched Plaque at Room Temperature";

[0088] The corrosion rate was evaluated according to ASTM G31-72 "Standard Guide for Laboratory Immersion Corrosion Testing of Metals";

[0089] The biocompatibility was evaluated according to GB / T 16886 "Biological Evaluation of Medical Devices - Part 5: In Vitro Cytotoxicity Tests";

[0090] The stress corrosion sensitivity was evaluated according to GB / T 15970.1-2018 "Corrosion Stress Corrosion Testing of Metals and Alloys".

[0091] Embodiments 1-15

[0092] The composition, preparation and performance test of the high-performance ternary near-pure zinc alloy.

[0093] The chemical composition of the 15 embodiments of the high-performance ternary near-pure zinc alloy composition is shown in Table 1-1. The preparation and processing flow of the near-pure zinc alloy is: alloy smelting→ homogenization heat treatment→ pass rolling→ water quenching.

[0094] The ingredients of Examples 1-15 shown in Table 1-1 were used for batching, wherein the raw material Zn was pure zinc with a purity of more than 99.99%, and the pure zinc alloy ingot was obtained by repeatedly melting 5 times under argon protection using an induction heating furnace; the melting point of the alloy was higher than 2000℃, and Al2O3 ceramic crucible was used for melting the alloy; the principle for selecting the crucible material was to select a ceramic material with a melting point at least 800℃ higher than that of pure zinc, so as to avoid chemical contamination of the alloy by the crucible material; the melting was carried out in two steps, first heating to 500℃, holding for 1 min, then cooling to 420℃, holding for 1 min, so as to promote the co-segregation of the alloying elements at the Zn grain boundaries; then the alloy melt was poured into a mold and cooled to room temperature.

[0095] Electromagnetic stirring was applied during the melting process, wherein the frequency of the electromagnetic stirring was 900HZ, which was beneficial to improving the purity and quality of the pure zinc alloy ingot; KCl melt covering agent was also added during the melting process, which was beneficial to reducing the oxidation of the metal and the formation of impurities, and improving the purity of the pure zinc alloy ingot.

[0096] The temperature of the homogenization heat treatment was 360℃, and the furnace was cooled after holding for 6h.

[0097] The temperature of the hole type rolling was 200℃, the holding time before rolling was 0.5h, the rolling speed was 0.2m / s, the single pass deformation was 25%-30%, and the total deformation was 98%; since the inventive alloys 1-15 in Table 1-1 had good processing formability, the rolling passes did not need to be annealed, and the surface quality of the final rolled wire was good, and no cracks appeared on the surface; as a comparison, the surface of the Zn-0.4Li and Zn-0.8Li alloy wires prepared by the same method had cracks.

[0098] The hole type rolling was immediately water quenched, which was beneficial to promoting the co-segregation of the alloying elements at the Zn grain boundaries, and inhibiting the growth of the zinc grains, so as to avoid the reduction of the alloy strength.

[0099] The microstructure of the pure zinc alloys of Examples 1-15 in Table 1-1 was observed by transmission electron microscopy (TEM), and it was found that the added alloying elements co-segregated at the grain boundaries. The TEM microstructure of the co-segregation of Mn and Mg elements at the grain boundaries in Example 2 is shown in Figure 1; the Zn-0.6Mn, Zn-0.8Mn and Zn-1Mn alloys prepared by the same method did not have the grain boundary segregation phenomenon.

[0100] The microstructure of the pure zinc alloys of Examples 1-15 in Table 1-1 was observed by electron backscatter diffraction (EBSD), and it was measured that the average size of the Zn grains of these inventive alloys was ≤1.5μm, the volume fraction of the second phase particles was ≤1.6%, the size (i.e. equivalent diameter) of the second phase particles was ≤1μm, and the dislocation density was ≤1.5×10 14 m -2; the Zn grain size of the inventive alloys of Examples 1-15 is ≤ 2 μm and the microstructure is stable after heat treatment at 100 °C in air for 10 h; the Zn grain size of Example 5 in Table 1-1 is shown in Fig. 2.

[0101] The recrystallization temperature of the near-pure zinc alloys of Examples 1-15 in Table 1-1 is measured to be 80-120 °C. The recrystallization temperature of the pure zinc alloy prepared in the same way is measured to be 15-25 °C; this indicates that the trace elements added in the near-pure zinc alloys can significantly increase the recrystallization temperature of the zinc matrix.

[0102] The room temperature tensile properties of the near-pure zinc alloys of Examples 1-15 in Table 1-1 are measured to be: yield strength 250-405 MPa, tensile strength 320-500 MPa, elongation 25%-156%; the strength decreases by ≤ 3% and the elongation decreases by ≤ 5% after storage in air at 37 °C for 1 year; the room temperature tensile properties of the pure zinc alloy prepared in the same way are: yield strength 30-50 MPa, tensile strength 80-120 MPa, elongation 5%-35%, and the strength decreases by ≥ 40% after storage in air at 37 °C for 1 year. The co-segregation structure at the Zn grain boundaries of the near-pure zinc alloys of Examples 1-15 can significantly improve the room temperature mechanical properties of the materials and maintain the stability of the mechanical properties. The tensile mechanical properties of Example 2 are shown in Fig. 3.

[0103] The maximum bending force of the near-pure zinc alloys of Examples 1-15 in Table 1-1 is measured to be 2.3-5 kN, and the maximum bending force of the pure zinc alloy, Zn-1Mn, Zn-1.5Cu, Zn-0.6Fe, Zn-0.6Ca, etc. prepared in the same way is ≤ 0.8 kN. The comparison of the maximum bending force of Example 8 and the pure zinc alloy is shown in Fig. 4.

[0104] The degradation mode of the near-pure zinc alloys of Examples 1-15 in Table 1-1 in SBF at 37 °C is uniform degradation, and the size of the corrosion pits (i.e. the equivalent diameter) is ≤ 8 μm, the standard deviation is ≤ 1.2 μm, the uniformity coefficient of the distribution of the corrosion pits is ≥ 89%, and the degradation rate is 0.02-0.5 mm / y after immersion in SBF at 37 °C for 60 days; the degradation mode of the pure zinc alloy, Zn-0.6Mn, Zn-0.8Mn, Zn-1Mn, Zn-1Cu, Zn-2Cu, Zn-0.8Fe, Zn-0.8Ca, etc. prepared in the same way in SBF at 37 °C is local corrosion, and the size of the corrosion pits (i.e. the equivalent diameter) is ≥ 35 μm, the standard deviation is ≥ 15 μm, and the uniformity coefficient of the distribution of the corrosion pits is ≤ 50%. The morphology of the corrosion pits after removal of the corrosion products of Example 10 after immersion in SBF at 37 °C for 60 days is shown in Fig. 5.

[0105] The stress corrosion sensitivity factor of the near-pure zinc alloys of Examples 1-15 in Table 1-1 is measured to be less than or equal to 10%, and the stress corrosion sensitivity factor of the pure zinc, Zn-0.6Mn, Zn-0.8Mn, Zn-1Mn, Zn-1Cu, Zn-2Cu, Zn-0.8Fe, Zn-0.8Ca and the like alloys prepared by the same method is greater than or equal to 20%.

[0106] The cell survival rate of the near-pure zinc alloys of Examples 1-15 in Table 1-1 is measured to be greater than or equal to 80% for human aortic smooth muscle cells (HASMC), endothelial cells (human umbilical vein endothelial cells, HUVEC) and mouse embryonic osteoblasts (MC3T3-E1), and the antibacterial property of the near-pure zinc alloys is greater than or equal to 90% for Escherichia coli and Staphylococcus aureus.

[0107] The properties of the near-pure zinc alloys of some examples and the comparative examples are shown in Table 1-2.

[0108] Table 1-1

[0109] Table 1-2

[0110] Examples 16-30

[0111] Composition, preparation and property testing of high-performance quaternary near-pure zinc alloys.

[0112] The chemical compositions of 15 examples of the high-performance quaternary near-pure zinc alloy compositions are shown in Table 2-1. The preparation process of the near-pure zinc alloys is as follows: alloy smelting, solid solution heat treatment, groove rolling, water quenching, rolling and oil quenching.

[0113] The ingredients of Examples 16-30 shown in Table 2-1 are used for batching, wherein the raw material Zn is pure zinc with a purity greater than 99.99%, and the corresponding near-pure zinc alloy ingots are obtained by repeatedly smelting 6 times in an induction heating furnace under argon protection; the smelting alloy adopts an Al2O3 ceramic crucible with a melting point higher than 2000℃, and the principle for selecting the crucible material is to select a ceramic material with a melting point at least 800℃ higher than that of pure zinc, so as to avoid chemical contamination of the alloy by the crucible material; the smelting is carried out in two steps, first heating to 510℃ and holding for 2 min, and then cooling to 430℃ and holding for 1 min, so as to promote the co-segregation of alloying elements at the Zn grain boundaries; then the alloy melt is poured into a mold and cooled to room temperature.

[0114] Electromagnetic stirring is applied during the smelting process, and the frequency of the electromagnetic stirring is 1000HZ, which is beneficial to improving the purity and quality of the near-pure zinc alloy ingot; NaCl melt covering agent is also added during the smelting process, which is beneficial to reducing metal oxidation and impurity formation and improving the purity of the near-pure zinc alloy ingot.

[0115] Solution heat treatment temperature is 360℃, holding for 16h and then water quenching.

[0116] The temperature of the hole type rolling is 230℃, holding for 1h before rolling, the rolling speed is 0.3m / s, the single pass deformation is 28%~35%, and the total deformation is 98%; since the inventive alloy 16-30 in Table 2-1 has good processing formability, the rolling pass does not need to be annealed, and the surface quality of the final rolling wire is good, and no cracks appear on the surface; as a comparison, the surface of the Zn-0.8Ca and Zn-1Fe alloy wire prepared by the same method appears cracks.

[0117] The hole type rolling is immediately water quenched after completion, on the one hand to promote the co-segregation of alloying elements at the Zn grain boundary, and on the other hand to inhibit the growth of zinc grains and avoid the reduction of alloy strength.

[0118] The rolling temperature is 200℃, holding for 30min before rolling, the rolling speed is 1m / s, the single pass deformation is 32%~37%, and the total deformation is 99%. The rolling is immediately oil quenched after completion.

[0119] The microstructure of the near-pure zinc alloy in Table 2-1 is observed by transmission electron microscopy (TEM), and it is found that the added alloying elements co-segregate at the grain boundary; the Zn-0.6Ag, Zn-0.8Ag and Zn-1Ag alloys prepared by the same method do not have grain boundary segregation.

[0120] The microstructure of the near-pure zinc alloy 16-30 in Table 2-1 is observed by electron backscatter diffraction (EBSD), and it is measured that the average size of Zn grains is ≤1.2μm, the volume fraction of the second phase particles is ≤2%, the size (i.e. equivalent diameter) of the second phase particles is ≤1μm, and the dislocation density is ≤1.5×10 14 m -2 ; after holding for 50h in air atmosphere at 120℃, the average size of Zn grains is ≤4μm, and it has good microstructure stability.

[0121] The recrystallization temperature of the near-pure zinc alloy 16-30 in Table 2-1 is measured to be 86~130℃. The recrystallization temperature of the pure zinc prepared by the same method is 15~26℃, which shows that the trace elements added in the near-pure zinc alloy can significantly improve the recrystallization temperature of the zinc matrix.

[0122] The room temperature tensile properties of the near-pure zinc alloys of Examples 16-30 in Table 2-1 were measured to be: yield strength 270-420 MPa, tensile strength 340-530 MPa, elongation 28%-161%; the strength reduction amplitude was ≤2% and the elongation reduction amplitude was ≤4% after 1 year storage in 37°C air; the room temperature tensile properties of the pure zinc of Comparative Example prepared in the same way were: yield strength 30-45 MPa, tensile strength 68-110 MPa, elongation 5%-30%; the strength reduction amplitude was ≥46% and the elongation reduction amplitude was ≥35% after 1 year storage in 37°C air. It can be seen that the co-segregation structure on the Zn grain boundary of the near-pure zinc alloys of Examples 16-30 can significantly improve the room temperature mechanical properties of the material and maintain the stability of the mechanical properties.

[0123] The maximum bending force of the near-pure zinc alloys of Examples 16-30 in Table 2-1 was measured to be 2.5-5 kN, and the maximum bending force of the pure zinc, Zn-1Mn, Zn-1Cu, Zn-1Fe and other alloys of Comparative Example prepared in the same way was ≤0.7 kN.

[0124] The degradation mode of the near-pure zinc alloys of Examples 16-30 in Table 2-1 in SBF at 37°C was uniform degradation, and the corrosion pit size (i.e. equivalent diameter) was ≤12 μm and the standard deviation was ≤1.2 μm after 60 days of immersion, and the degradation rate was 0.04-0.6 mm / y; the degradation mode of the pure zinc, Zn-0.7Mn, Zn-1Mn, Zn-2Cu, Zn-3Cu, Zn-0.6Fe, Zn-0.6Ca and other alloys of Comparative Example prepared in the same way in SBF at 37°C was local corrosion, and the corrosion pit size (i.e. equivalent diameter) was ≥40 μm and the standard deviation was ≥18 μm after 60 days of immersion, and the uniformity coefficient of the corrosion pit distribution was ≤45%.

[0125] The stress corrosion sensitivity factor of the near-pure zinc alloys of Examples 16-30 in Table 2-1 was ≤8%, and the stress corrosion sensitivity factor of the pure zinc, Zn-0.6Ag, Zn-0.8Mn, Zn-1Mn, Zn-0.6Fe, Zn-0.8Cu of Comparative Example prepared in the same way was ≥25%.

[0126] The cell compatibility of the near-pure zinc alloys of Examples 16-30 in Table 2-1 with human aortic smooth muscle cells (HASMC), fibroblasts (human aortic adventitial fibroblasts, HAAF), endothelial cells (human umbilical vein endothelial cells, HUVEC), mouse embryonic osteoblasts (MC3T3-E1) was ≥80%, and the antibacterial property against Escherichia coli and Staphylococcus aureus was ≥90%.

[0127] The properties of some of the near-pure zinc alloys of Examples and Comparative Examples are shown in Table 2-2.

[0128] Table 2-1

[0129] Table 2-2

[0130] Examples 31-45

[0131] Composition, preparation and performance test of high-performance five-element near-pure zinc alloy.

[0132] The chemical composition of 15 examples of the high-performance five-element near-pure zinc alloy composition is shown in Table 3-1. The preparation process of the near-pure zinc alloy is: alloy smelting → solid solution heat treatment → aging heat treatment → high-pressure torsion → water quenching.

[0133] According to the compositions of examples 31-45 shown in Table 3-1, the raw material Zn is selected to be pure zinc with a purity of more than 99.99%, and the corresponding near-pure zinc alloy ingot is obtained by repeatedly smelting 7 times in an induction heating furnace under argon protection; the smelted alloy adopts ceramic crucible with a melting point higher than 2000℃, and the principle of selecting the crucible material is to select ceramic material with a melting point at least 800℃ higher than that of pure zinc, so as to avoid chemical contamination of the alloy by the crucible material; the smelting is carried out in two steps, first heating to 510℃, holding for 1 min, then cooling to 430℃, holding for 2 min, so as to promote the co-segregation of alloying elements at the Zn grain boundary; then the alloy melt is poured into a mold and cooled to room temperature.

[0134] Electromagnetic stirring is applied during the smelting process, and the frequency of the electromagnetic stirring is 1200HZ, which is beneficial to improve the purity and quality of the near-pure zinc alloy ingot; MgCl2 melt covering agent is also added during the smelting process, which is beneficial to reduce metal oxidation and impurity formation and improve the purity of the near-pure zinc alloy ingot.

[0135] The solid solution heat treatment temperature is 360℃, and the water quenching is carried out after holding for 20h.

[0136] The aging heat treatment temperature is 100℃, and the holding time is 0.1-6h.

[0137] The high-pressure torsion temperature is 260℃, the holding time before deformation is 30min, the applied pressure is 2GPa, the deformation number is 3, and the torsion speed is 1r / min.

[0138] Immediately after high-pressure torsion, water quenching is carried out, which on the one hand promotes the co-segregation of alloying elements at the Zn grain boundary, and on the other hand inhibits the growth of zinc grains and avoids the reduction of alloy strength.

[0139] The microstructure of the near-pure zinc alloys of Examples 31-45 in Table 3-1 was observed by transmission electron microscopy (TEM), and it was found that the added alloying elements were co-segregated at the grain boundaries. The alloys of Comparative Examples Zn-0.6Ag, Zn-0.8Ca and Zn-1Mn prepared in the same way did not show grain boundary segregation.

[0140] The microstructure of the near-pure zinc alloys of Examples 31-45 in Table 3-1 was observed by electron backscatter diffraction (EBSD), and it was found that the average size of the Zn grains was ≤1 μm, the volume fraction of the second phase particles was ≤2%, the size (i.e. the equivalent diameter) of the second phase particles was ≤1 μm, and the dislocation density was ≤1.8 x 1014m-2. 14 -2 The recrystallization temperature of the near-pure zinc alloys of Examples 31-45 in Table 3-1 was measured to be 95-138°C. The recrystallization temperature of pure zinc prepared in the same way was measured to be 15-28°C, which shows that the trace elements added to the near-pure zinc alloys can significantly increase the recrystallization temperature of the zinc matrix.

[0141] The recrystallization temperature of the near-pure zinc alloys of Examples 31-45 in Table 3-1 was measured to be 95-138°C. The recrystallization temperature of pure zinc prepared in the same way was measured to be 15-28°C, which shows that the trace elements added to the near-pure zinc alloys can significantly increase the recrystallization temperature of the zinc matrix.

[0142] The room temperature tensile properties of the near-pure zinc alloys of Examples 31-45 in Table 3-1 were measured to be: yield strength 280-430 MPa, tensile strength 350-550 MPa, and elongation 25%-148%. The strength reduction after storage in air at 37°C for 1 year was ≤2%, and the elongation reduction was ≤5%. The room temperature tensile properties of pure zinc prepared in the same way were: yield strength 40 MPa-48 MPa, tensile strength 70 MPa-115 MPa, and elongation 2%-30%. The strength reduction after storage in air at 37°C for 1 year was ≥45%, and the elongation reduction was ≥33%. It can be seen that the co-segregation structure on the Zn grain boundaries of the near-pure zinc alloys of Examples 31-45 can significantly improve the room temperature mechanical properties of the material and maintain the stability of the mechanical properties.

[0143] The maximum bending force of the near-pure zinc alloys of Examples 31-45 in Table 3-1 was measured to be 2.6-5.3 kN. The maximum bending force of pure zinc, Zn-0.8Mn, Zn-1Cu, Zn-1Ca, Zn-0.6Ga and Zn-0.6Al alloys prepared in the same way was ≤0.7 kN.

[0144] ​The degradation mode of the near-pure zinc alloys of Examples 31-45 in Table 3-1 in SBF at 37°C was measured to be uniform degradation, and the corrosion pit size (i.e. equivalent diameter) was ≤ 13 μm and the standard deviation of the corrosion pit size was ≤ 1.8 μm after 60 days of immersion, and the degradation rate was 0.07-0.8 mm / y. The degradation mode of the comparative pure zinc, Zn-1Mn, Zn-1Zr, Zn-0.8Sr, Zn-0.8Cu, Zn-0.8Ag, and Zn-1Ca alloys prepared in the same manner in SBF at 37°C was local corrosion, and the corrosion pit size (i.e. equivalent diameter) was ≥ 42 μm and the standard deviation was ≥ 20 μm, and the uniformity coefficient of the corrosion pit distribution was ≤ 40%.

[0145] The stress corrosion sensitivity factor of the near-pure zinc alloys of Examples 31-45 in Table 3-1 was measured to be ≤ 7%, and the stress corrosion sensitivity factor of the comparative pure zinc, Zn-1Mn, Zn-1Zr, Zn-0.8Sr, Zn-0.8Cu, Zn-0.8Ag, and Zn-1Ca alloys prepared in the same manner was ≥ 40%.

[0146] The cell survival rate of the near-pure zinc alloys of Examples 31-45 in Table 3-1 on human aortic smooth muscle cells (HASMC), endothelial cells (human umbilical vein endothelial cells, HUVEC), and mouse embryonic osteoblast cells (MC3T3-E1) was measured to be ≥ 80%, and the antibacterial property on E. coli and S. aureus was ≥ 90%.

[0147] The properties of some of the near-pure zinc alloys of the examples and the comparative examples are shown in Table 3-2.

[0148] Table 3-1

[0149] Table 3-2

[0150] Examples 46-52

[0151] High-performance multi-element near-pure zinc alloys

[0152] The chemical compositions of 15 examples of the high-performance multi-element near-pure zinc alloy compositions are shown in Table 4-1, and the "multi-element" means that the alloy composition contains at least 6 elements. The preparation process of the near-pure zinc alloys is: alloy smelting → solid solution heat treatment → two-stage aging heat treatment → equal channel angular extrusion → water quenching.

[0153] The ingredients of Examples 46-60 shown in Table 4-1 were used for batching, wherein the raw material Zn was pure zinc with a purity of more than 99.99%, and the pure zinc alloy ingot was obtained by repeatedly melting 8 times under argon protection by an induction heating furnace; the melting point of the ceramic crucible, such as Al2O3, used for melting the alloy was higher than 2000℃, and the principle for selecting the crucible material was to select a ceramic material with a melting point at least 800℃ higher than that of pure zinc, so as to avoid chemical contamination of the alloy by the crucible material; the melting was carried out in two steps, first heating to 520℃, holding for 3 min, and then cooling to 420℃, holding for 3 min, so as to promote the co-segregation of the alloy elements at the Zn grain boundaries; then the alloy melt was poured into a mold and cooled to room temperature.

[0154] Electromagnetic stirring was applied during the melting process, wherein the frequency of the electromagnetic stirring was 1500HZ, so as to improve the purity and quality of the pure zinc alloy ingot; borax melt covering agent was also added during the melting process, so as to reduce the oxidation of the metal and the formation of impurities and improve the purity of the pure zinc alloy ingot.

[0155] The solid solution heat treatment temperature was 360℃, and the water quenching was carried out after holding for 20h.

[0156] The first stage aging heat treatment temperature of the two-stage aging heat treatment was 60℃, and the holding time was 1h; the second stage aging heat treatment temperature was 100℃, and the holding time was 3h.

[0157] The equal channel angular extrusion temperature was 260℃, the extrusion pass was 15-25, the extrusion speed was 10mm / s, and the total deformation was 99.5%. Since the inventive alloys 46-60 in Table 4-1 had good processing formability, the equal channel angular extrusion passes did not need to be annealed, and the surface quality of the final wire was good without cracks; as a comparison, the surface of the Zn-0.6Fe and Zn-0.8Sr alloy wires prepared by the same method had cracks.

[0158] The equal channel angular extrusion was immediately water quenched, on the one hand to promote the co-segregation of the alloy elements at the Zn grain boundaries, and on the other hand to inhibit the growth of the zinc grains and avoid the reduction of the alloy strength.

[0159] The microstructure of the pure zinc alloys of Examples 46-60 in Table 4-1 was observed by transmission electron microscopy (TEM), and it was found that the added alloy elements co-segregated at the grain boundaries. The Zn-0.8Ca, Zn-0.8Mn and Zn-1Fe alloys prepared by the same method did not have grain boundary segregation.

[0160] The microstructure of the near-pure zinc alloys of Examples 46-60 in Table 4-1 was observed by electron backscatter diffraction (EBSD), and the average size of Zn grains was measured to be ≤1 μm, the volume fraction of second phase particles was measured to be ≤2%, the size (i.e. equivalent diameter) of second phase particles was measured to be ≤1 μm, and the dislocation density was measured to be ≤1.9 x 1014 m-2. 14 m -2 ; and the average size of Zn grains was measured to be ≤3 μm after being kept at 200 °C in air for 26 h, and the microstructure was stable.

[0161] The recrystallization temperature of the near-pure zinc alloys of Examples 46-60 in Table 4-1 was measured to be 100-146 °C. The recrystallization temperature of the pure zinc of the comparative example prepared in the same way was measured to be 15-30 °C, which indicates that the trace elements added in the near-pure zinc alloys can significantly increase the recrystallization temperature of the zinc matrix.

[0162] The room temperature tensile properties of the near-pure zinc alloys of Examples 46-60 in Table 4-1 were measured to be: yield strength 300-450 MPa, tensile strength 380-580 MPa, and elongation 25%-95%; the strength reduction amplitude was ≤2% and the elongation reduction amplitude was ≤5% after being stored in air at 37 °C for 1 year. The room temperature tensile properties of the pure zinc of the comparative example prepared in the same way were measured to be: yield strength 40-60 MPa, tensile strength 70-130 MPa, and elongation 5%-35%; the strength reduction amplitude was ≥50% and the elongation reduction amplitude was ≥38% after being stored in air at 37 °C for 1 year. It can be seen that the co-segregation structure on the Zn grain boundaries of the near-pure zinc alloys of Examples 46-60 can significantly improve the room temperature mechanical properties of the material and maintain the stability of the mechanical properties.

[0163] The maximum bending force of the near-pure zinc alloys of Examples 46-60 in Table 4-1 was measured to be 2.8-5.5 kN. The maximum bending force of the pure zinc, Zn-0.8Ca, Zn-1Fe, Zn-0.6Si, Zn-0.6Al, and other alloys of the comparative examples prepared in the same way was ≤0.5 kN.

[0164] The degradation mode of the near-pure zinc alloys of Examples 46-60 in Table 4-1 in SBF at 37 °C was measured to be uniform degradation, the size (i.e. equivalent diameter) of the corrosion pits after immersion for 60 days was ≤15 μm, the standard deviation of the size of the corrosion pits was ≤3 μm, and the degradation rate was 0.07-1.5 mm / y. The degradation mode of the pure zinc, Zn-0.6Ti, Zn-0.8Zr, Zn-1Mn, Zn-1Ga, Zn-2Al, Zn-0.8Si, Zn-0.8C, and other alloys of the comparative examples prepared in the same way in SBF at 37 °C was local corrosion, the size (i.e. equivalent diameter) of the corrosion pits after immersion for 60 days was ≥45 μm, the standard deviation was ≥30 μm, and the uniformity coefficient of the distribution of the corrosion pits was ≤46%.

[0165] The stress corrosion sensitivity factor of the near-pure zinc alloys of Examples 46-60 in Table 4-1 was measured to be ≤ 6%, while the stress corrosion sensitivity factor of the comparative pure zinc, Zn-0.8Sr, Zn-1Mn, Zn-1Ga, Zn-5Al, Zn-1Si, Zn-0.8C alloys prepared in the same manner was ≥ 42%.

[0166] The cell survival rate of the near-pure zinc alloys of Examples 46-60 in Table 4-1 was measured to be ≥ 80% for human aortic smooth muscle cells (HASMC), endothelial cells (human umbilical vein endothelial cells, HUVEC), mouse embryonic osteoblast cells (MC3T3-E1), and the antibacterial property was ≥ 90% for E. coli and Staphylococcus aureus bacteria.

[0167] The properties of the near-pure zinc alloys of some examples and the comparative examples are shown in Table 4-2.

[0168] Table 4-1

[0169] Table 4-2

Claims

1. A high-performance near-pure zinc alloy, characterized in that, the near-pure zinc alloy has a composition in atomic percentage (%) of Zn≥99.5%, and the balance being artificially added trace alloying elements; the near-pure zinc alloy has a yield strength≥250 MPa, a tensile strength≥320 MPa, an elongation≥25%, a mechanical property change range within 1 year of room temperature storage≤5%, a maximum bending force≥2 kN, and a stress corrosion sensitivity factor≤15%; the near-pure zinc alloy has high degradation uniformity, and after immersion for 60 days, the corrosion pit size, i.e. the equivalent diameter, is≤15 μm, the standard deviation is≤3 μm, and the uniformity coefficient of the corrosion pit distribution is≥80%. 2.The high-performance near-pure zinc alloy according to claim 1, characterized in that, the near-pure zinc alloy has a composition in atomic percentage (%) of a total amount of artificially added alloying elements≤0.5%, and includes at least two of the following 14 elements: Mg, Mn, Li, Cu, Ag, Ca, Sr, Fe, Zr, Ti, Al, C, Ga, and Si. 3.The high-performance near-pure zinc alloy according to claim 1, characterized in that, the near-pure zinc alloy has a volume fraction of second phase particles≤2%, and the size, i.e. the equivalent diameter, of the second phase particles≤1 μm. 4.The high-performance near-pure zinc alloy according to claim 1, characterized in that, The average size of Zn crystal grains in the near-pure zinc alloy is less than or equal to 2 microns, and the dislocation density is less than or equal to 2*10 14 m -2 ; and the average size of Zn crystal grains is less than or equal to 10 microns after being kept at 37-200 DEG C for 5-100 hours in an air atmosphere.

5. A method of producing a high-performance near-pure zinc alloy according to any one of claims 1 to 4, characterized in that, the preparation method of the near-pure zinc alloy includes alloy smelting, heat treatment, large plastic deformation, and rapid cooling.

6. The high performance near-pure zinc alloy and method of making of claims 1-5, wherein, In the near-pure zinc alloy, a co-segregation structure of two or more of Mg, Mn, Li, Cu, Ag, Ca, Sr, Fe, Zr, Ti, Al, C, Ga, and Si is formed at grain boundaries, sub-grain boundaries, twin boundaries, and dislocation defects, and no intermetallic compound second phase particles are formed. 7.The preparation method of the high-performance near-pure zinc alloy according to claim 5, characterized in that, the smelting process of the near-pure zinc alloy uses pure metals corresponding to each element in the near-pure zinc alloy as raw materials, wherein the raw material Zn is pure zinc with a purity greater than 99.99%, and the near-pure zinc alloy ingot is obtained by smelting 3-10 times under vacuum or inert gas protection. 8.The preparation method of the high-performance near-pure zinc alloy according to claim 7, characterized in that, the smelting conditions of the near-pure zinc alloy are as follows: the smelting alloy uses an Al2O3 ceramic crucible with a melting point higher than 2000 ℃, and the principle of selecting the crucible material is to select a ceramic material with a melting point at least 800 ℃ higher than that of pure zinc; the smelting is performed in two steps, first heating to 480-550 ℃, holding for 1-3 min, and then cooling to 420-460 ℃, holding for 1-5 min. 9.The preparation method of the high-performance near-pure zinc alloy according to claim 7, characterized in that, the smelting process applies electromagnetic stirring, and the frequency of the electromagnetic stirring is 800-3000 HZ; at least one of KCl, NaCl, MgCl2, LiCl, and borax is added as a molten covering agent. 10.The preparation method of the high-performance near-pure zinc alloy according to claim 5, characterized in that, The heat treatment is at least one of homogenization heat treatment, solid solution heat treatment, aging heat treatment, and two-stage aging heat treatment.

11. The method according to claim 5, wherein the high-performance near-pure zinc alloy is prepared by the following steps: (1) preparing a high-performance near-pure zinc alloy by the method according to any one of claims 1 to 4; and (2) performing a heat treatment on the high-performance near-pure zinc alloy prepared in step (1). The heat treatment includes but is not limited to the following four ways: (1) homogenization heat treatment; (2) solid solution heat treatment; (3) solid solution heat treatment followed by aging heat treatment; (4) solid solution heat treatment followed by two-stage aging heat treatment.

12. The method according to claim 11, wherein the homogenization heat treatment is performed at a temperature of 200-360℃ for 3-10h; the solid solution heat treatment is performed at a temperature of 300-360℃ for 8-20h; the aging heat treatment is performed at a temperature of 50-180℃ for 0.1-12h; and the two-stage aging heat treatment is performed at a first-stage aging heat treatment temperature of 50-80℃ for 5min-6h and a second-stage aging heat treatment temperature of 100-150℃ for 5min-10h. The cooling mode after the heat treatment is any one of air cooling, furnace cooling, water quenching, and oil quenching.

13. The method according to claim 5, wherein the large plastic deformation is at least one of groove rolling, rolling, equal channel angular pressing, high-pressure torsion, and high-speed impact.

14. The method according to claim 5 or 13, wherein the large plastic deformation is performed at a temperature of -50-320℃ for 15min-3h before deformation; and the single-pass deformation amount of the large plastic deformation is ≥20% and the total deformation amount is ≥98%.

15. The method according to claim 13, wherein the groove rolling is performed at a rolling speed of 0.05-0.6m / s, a single-pass deformation amount of 20%-28%, and a total deformation amount of 98%-99%; the rolling is performed at a single-pass rolling deformation amount of 30%-45%, a rolling speed of 0.5-2.5m / s, and a total deformation amount of 98%-99.5%; the equal channel angular pressing is performed at an extrusion pass number of 10-25, an extrusion speed of 1-20mm / s, and a total deformation amount of 98%-99.7%; the high-pressure torsion is performed at an applied pressure of 0.5-6GPa, a deformation number of 2-6, and a torsion speed of 0.3-2r / min; and the high-speed impact is performed at an impact speed of 10-100m / s, an impact load of 100-1000N, an impact angle of 45-60°, and an impact time of 0.1-1s.

16. The method according to claim 5, wherein the rapid cooling mode after the large plastic deformation is any one of water bath quenching, oil bath quenching, and liquid nitrogen quenching. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 17. Use of a high performance near-pure zinc alloy prepared according to the method of claims 5-16, characterized in that, The alloy can be applied to degradable stents, bone implant devices, intestinal, vascular or nerve anastomat or anastomat nail, vascular clamp, guided bone regeneration membrane, guided tissue regeneration membrane, artificial heart valve, meningeal repair membrane, soluble bridge plug for oil drilling, soluble fracturing ball, zinc alloy die casting, electroplated zinc material, building zinc material, battery zinc material, printing zinc material, preparation of zinc-based alloy solder.

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