Heavy rare earth magnesium alloy wire for electric arc additive manufacturing and preparation method of heavy rare earth magnesium alloy wire

Abstract

The invention discloses a heavy rare earth magnesium alloy wire for electric arc additive manufacturing, which comprises the following components in percentage by mass: 8.0 to 12.0 percent of Gd, 2.0 to 5.0 percent of Y, 0.5 to 2.0 percent of Nd, 0.5 to 2.0 percent of Zn, 0.2 to 0.5 percent of Zr and the balance of Mg and inevitable impurities. By adopting specific components and component proportions, the heavy rare earth magnesium alloy wire has good strength and plasticity, and can meet the requirement for continuous forming of electric arc additive manufacturing; the result of the embodiment shows that the tensile strength of the heavy rare earth magnesium alloy wire is 424-466 MPa, the yield strength of the heavy rare earth magnesium alloy wire is 388-435 MPa, and the elongation of the heavy rare earth magnesium alloy wire is 1.89-2.51%.

Description

Technical Field

[0001] The present invention belongs to the field of arc additive manufacturing materials and preparation processes, and in particular relates to a heavy rare earth magnesium alloy wire for arc additive manufacturing and a preparation method thereof. Background Art

[0002] Magnesium alloy is the lightest metal structural material at present, and has broad application prospects in aerospace, automobile, military industry, electronics and other fields. As a structural material, mechanical properties are one of the most important indicators. Unfortunately, compared with traditional non-ferrous metal structural materials such as aluminum alloy and titanium alloy, the low strength seriously limits the large-scale application of magnesium alloy, especially in high-tech fields such as aerospace, national defense and military industry.

[0003] A large number of studies have shown that rare earth magnesium alloy is the most promising ultra-high strength magnesium alloy system. The introduction of an appropriate amount of rare earth can improve the fluidity of the magnesium alloy melt and reduce defects such as shrinkage cavities and microcracks. Among them, the representative Mg-Gd-Y based alloy has a strength of more than 500MPa, which is comparable to medium-strength deformed aluminum alloys.

[0004] When manufacturing rare earth magnesium alloy components using traditional casting, forging and other processes, there are problems such as long cycle, high cost, low material utilization rate, and poor product adaptability, which greatly limits the application field of magnesium alloy; arc additive manufacturing is a technology that uses electric arc as a heat source to melt metal wire and deposit it layer by layer to directly form metal blank parts. It has the advantages of high forming efficiency, low equipment cost, high wire utilization rate, stable and controllable forming process, and suitability for rapid manufacturing of large-size complex parts. Therefore, it has significant advantages in the manufacturing of complex rare earth magnesium alloy components.

[0005] Usually, the raw material used for arc additive manufacturing of rare earth magnesium alloy is φ1.2mm wire. However, due to the high deformation resistance and poor formability of rare earth magnesium alloy, the preparation of wire is difficult. With the rapid development of high-end equipment such as aerospace, the demand for rare earth magnesium alloy wire is also increasing. Therefore, it is urgent to develop heavy rare earth magnesium alloy wire grades and their preparation technology. Summary of the invention

[0006] The object of the present invention is to provide a heavy rare earth magnesium alloy wire for arc additive manufacturing and a preparation method thereof. The heavy rare earth magnesium alloy wire prepared by this preparation method has good strength and plasticity and can meet the needs of continuous forming in arc additive manufacturing.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The invention provides a heavy rare earth magnesium alloy wire for arc additive manufacturing, which comprises, by mass percentage, 8.0-12.0% of Gd, 2.0-5.0% of Y, 0.5-2.0% of Nd, 0.5-2.0% of Zn, 0.2-0.5% of Zr, and other impurities including Fe, Cu, Si, and Ni, with a total content of ≤0.3%, and the balance being Mg.

[0009] A further improvement of the above technical solution includes, by mass percentage, Gd: 8.0-9.0%, Y: 2-2.5%, Nd: 0.5-1.0%, Zn: 0.5-0.8%, Zr: 0.3-0.4%, and the remainder is Mg and unavoidable impurities.

[0010] A further improvement of the above technical solution includes, by mass percentage, Gd: 9.0-9.5%, Y: 2.5-3%, Nd: 1.0-1.2%, Zn: 0.8-1.0%, Zr: 0.3-0.4%, and the remainder is Mg and unavoidable impurities.

[0011] A further improvement of the above technical solution includes, by mass percentage, Gd: 9.5%, Y: 3.0%, Nd: 1.2%, Zn: 1.0%, Zr: 0.4%, and the balance is Mg and inevitable impurities.

[0012] A further improvement of the above technical solution includes, by mass percentage, Gd: 9.5%, Y: 3.0%, Nd: 1.2%, Zn: 1.0%, Zr: 0.4%, and the balance is Mg and inevitable impurities.

[0013] The present invention also provides a method for preparing a heavy rare earth magnesium alloy wire for arc additive manufacturing, comprising the following steps:

[0014] Step 1, melting the alloy raw material under vacuum conditions and then casting to obtain an ingot;

[0015] Step 2: homogenize the ingot obtained in step 1 to eliminate segregation; after turning into φ80mm extrusion billet, place the extrusion billet and the mold in a furnace for at least 1 hour, and then extrude to obtain φ5-6mm wire billet;

[0016] Step 3, the wire blank obtained in step 2 is subjected to continuous multiple-pass hot drawing to obtain a φ1.4-1.6 mm wire, and the wire and the die are lubricated with graphite before drawing;

[0017] Step 4: peeling the wire obtained in step 3 to remove graphite attached to the surface of the wire, thereby obtaining a φ1.2 mm heavy rare earth magnesium alloy wire for arc additive manufacturing;

[0018] Step 5, winding the wire obtained in step 4 to obtain a finished wire reel with a reel diameter of 400 mm.

[0019] Furthermore, the temperature of the homogenization treatment in step 2 is 500-520° C., and the holding time is 15-24 hours; the holding temperature and extrusion temperature in the furnace are 450-500° C., the extrusion speed is 5-10 mm / s, and the extrusion ratio is 30:1.

[0020] Furthermore, in step three, the drawing temperature is 400-450°C, the drawing speed is 1.5-3m / min, and when drawing from φ6mm to φ3mm, the deformation amount per pass is 15%, and 10 passes are required; when drawing from φ3mm to φ1.4mm, the deformation amount per pass is 10%, and 15 passes are required.

[0021] The heavy rare earth magnesium alloy wire for arc additive manufacturing provided by the present invention improves the tensile strength and fatigue strength of the alloy material by using an appropriate amount of Gd element. The solid solubility of Gd element in the magnesium matrix is ​​very high at high temperature and decreases rapidly with the decrease of temperature. The dislocation movement is effectively hindered through the solid solution strengthening and precipitation strengthening mechanisms (such as the formation of β′ phase and β″ phase), thereby improving the mechanical properties of the alloy material. An appropriate amount of Y element can not only improve the aging hardening characteristics of the alloy, improve the plasticity and ductility, but also form a stable eutectic phase (such as Mg 12 NdY) significantly enhances the creep resistance of the alloy; an appropriate amount of Nd element reduces the solid solubility of Gd in the matrix to generate a coherent DO19 structured β″ phase, inhibiting grain boundary slip and dislocation movement, thereby significantly improving the mechanical properties of the alloy; an appropriate amount of Zn element generates a 14H long period ordered (LPSO) phase at the grain boundary and in the grain under overaging conditions, enhancing the grain boundary and grain strength and improving the toughness of the alloy; an appropriate amount of Zr element, as an efficient grain refiner, promotes the peritectic reaction to form uniformly distributed dispersed nucleation particles, achieves grain refinement, and further improves the tensile strength and hardness of the alloy.

[0022] Under the joint action of various elements, the performance of the magnesium alloy wire is improved, so that it has good strength and plasticity, and can meet the needs of continuous forming in arc additive manufacturing; the results of the embodiment show that the heavy rare earth magnesium alloy wire provided by the present invention has a tensile strength of 424 to 466 MPa, a yield strength of 388 to 435 MPa, and an elongation of 1.89 to 2.51%. DETAILED DESCRIPTION

[0023] The technical solutions and effects of the present invention are further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0024] Example 1

[0025] The heavy rare earth magnesium alloy wire for arc additive manufacturing in this embodiment includes, by mass percentage, Gd8.0%, Y2.0%, Nd 0.5%, Zn 0.5%, Zr 0.2%, other impurities include Fe, Cu, Si, Ni, with a total content of 0.3%, and the balance is Mg.

[0026] The method for preparing the heavy rare earth magnesium alloy wire for arc additive manufacturing comprises the following steps:

[0027] Step 1: After melting the alloy raw materials under vacuum conditions, a φ85 mm ingot is obtained by a semi-continuous casting process;

[0028] Step 2: subject the ingot obtained in step 1 to high-temperature homogenization treatment at a temperature of 500°C for a holding time of 15 hours; after turning into a φ80 mm extrusion billet, the extrusion billet and the mold are placed in a furnace for holding at a temperature of 450°C for 1 hour, followed by extrusion at an extrusion temperature of 450°C, an extrusion speed of 5 mm / s, and an extrusion ratio of 30:1 to obtain a φ6 mm wire billet;

[0029] Step 3, the wire blank obtained in step 2 is subjected to continuous multiple-pass hot drawing processing, the wire and the die are lubricated with graphite before drawing, the drawing temperature is 400°C, the drawing speed is 1.5m / min, when drawing from φ6mm to φ3mm, the deformation amount of each pass is 15%, and 10 passes are required; when drawing from φ3mm to φ1.4mm, the deformation amount of each pass is 10%, and 15 passes are required to obtain φ1.4mm wire;

[0030] Step 4: peeling the wire obtained in step 3 to obtain a heavy rare earth magnesium alloy wire with a diameter of 1.2 mm for arc additive manufacturing;

[0031] Step 5: Wind the wire obtained in step 4 to obtain a finished wire reel with a reel diameter of 400 mm. The wire meets the requirements of the national standard "GB / T 41112-2021 Magnesium and Magnesium Alloy Welding Wire".

[0032] The mechanical properties of the prepared φ1.2mm heavy rare earth magnesium alloy wire were tested.

[0033] Example 2

[0034] The heavy rare earth magnesium alloy wire for arc additive manufacturing in this embodiment includes, by mass percentage, Gd12.0%, Y 5.0%, Nd 2.0%, Zn 2.0%, Zr 0.5%, other impurities include Fe, Cu, Si, Ni, the total content of which is 0.3%, and the balance is Mg.

[0035] The method for preparing the heavy rare earth magnesium alloy wire for arc additive manufacturing comprises the following steps:

[0036] Step 1: After melting the alloy raw materials under vacuum conditions, a φ85 mm ingot is obtained by a semi-continuous casting process;

[0037] Step 2: subject the ingot obtained in step 1 to high-temperature homogenization treatment at a temperature of 520°C for a holding time of 24 hours; after turning into a φ80 mm extrusion billet, the extrusion billet and the mold are placed in a furnace for holding at a temperature of 500°C for 2 hours, followed by extrusion at an extrusion temperature of 500°C, an extrusion speed of 10 mm / s, and an extrusion ratio of 30:1 to obtain a φ5 mm wire billet;

[0038] Step 3, the wire blank obtained in step 2 is subjected to continuous multiple-pass hot drawing processing, the wire and the die are lubricated with graphite before drawing, the drawing temperature is 450°C, the drawing speed is 3m / min, when drawing from φ5mm to φ3mm, the deformation amount of each pass is 15%, and 8 passes are required; when drawing from φ3mm to φ1.6mm, the deformation amount of each pass is 10%, and 13 passes are required to obtain φ1.6mm wire;

[0039] Step 4: peeling the wire obtained in step 3 to obtain a heavy rare earth magnesium alloy wire with a diameter of 1.2 mm for arc additive manufacturing;

[0040] Step 5: Wind the wire obtained in step 4 to obtain a finished wire reel with a reel diameter of 400 mm. The wire meets the requirements of the national standard "GB / T 41112-2021 Magnesium and Magnesium Alloy Welding Wire".

[0041] The mechanical properties of the prepared φ1.2mm heavy rare earth magnesium alloy wire were tested.

[0042] Example 3

[0043] The heavy rare earth magnesium alloy wire for arc additive manufacturing in this embodiment includes, by mass percentage, Gd9.0%, Y2.5%, Nd1.0%, Zn0.8%, Zr0.3%, other impurities include Fe, Cu, Si, Ni, the total content of which is 0.2%, and the balance is Mg.

[0044] The method for preparing the heavy rare earth magnesium alloy wire for arc additive manufacturing comprises the following steps:

[0045] Step 1: After melting the alloy raw materials under vacuum conditions, a φ85 mm ingot is obtained by a semi-continuous casting process;

[0046] Step 2: subject the ingot obtained in step 1 to high-temperature homogenization treatment at a temperature of 510°C for 18 hours; after turning into a φ80 mm extrusion billet, the extrusion billet and the mold are placed in a furnace for insulation at a temperature of 470°C for 1 hour, followed by extrusion at an extrusion temperature of 470°C, an extrusion speed of 6 mm / s, and an extrusion ratio of 30:1 to obtain a φ6 mm wire billet;

[0047] Step 3, the wire blank obtained in step 2 is subjected to continuous multiple-pass hot drawing processing, the wire and the die are lubricated with graphite before drawing, the drawing temperature is 420°C, the drawing speed is 2m / min, when drawing from φ6mm to φ3mm, the deformation amount of each pass is 15%, and 10 passes are required; when drawing from φ3mm to φ1.4mm, the deformation amount of each pass is 10%, and 15 passes are required to obtain φ1.4mm wire;

[0048] Step 4: peeling the wire obtained in step 3 to obtain a heavy rare earth magnesium alloy wire with a diameter of 1.2 mm for arc additive manufacturing;

[0049] Step 5: Wind the wire obtained in step 4 to obtain a finished wire reel with a reel diameter of 400 mm. The wire meets the requirements of the national standard "GB / T 41112-2021 Magnesium and Magnesium Alloy Welding Wire".

[0050] The mechanical properties of the prepared φ1.2mm heavy rare earth magnesium alloy wire were tested.

[0051] Example 4

[0052] The heavy rare earth magnesium alloy wire for arc additive manufacturing in this embodiment includes, by mass percentage, Gd9.5%, Y3.0%, Nd1.2%, Zn1.0%, Zr0.4%, other impurities include Fe, Cu, Si, Ni, the total content of which is 0.1%, and the balance is Mg.

[0053] The method for preparing the heavy rare earth magnesium alloy wire for arc additive manufacturing comprises the following steps:

[0054] Step 1: After melting the alloy raw materials under vacuum conditions, a φ85 mm ingot is obtained by a semi-continuous casting process;

[0055] Step 2: subject the ingot obtained in step 1 to high-temperature homogenization treatment at a temperature of 510°C for a holding time of 20 hours; after turning into a φ80 mm extrusion billet, the extrusion billet and the mold are placed in a furnace for holding at a temperature of 470°C for 2 hours, followed by extrusion at an extrusion temperature of 470°C, an extrusion speed of 8 mm / s, and an extrusion ratio of 30:1 to obtain a φ6 mm wire billet;

[0056] Step 3, the wire blank obtained in step 2 is subjected to continuous multiple-pass hot drawing processing, the wire and the die are lubricated with graphite before drawing, the drawing temperature is 430°C, the drawing speed is 2.0m / min, when drawing from φ6mm to φ3mm, the deformation amount of each pass is 15%, and 10 passes are required; when drawing from φ3mm to φ1.4mm, the deformation amount of each pass is 10%, and 15 passes are required to obtain φ1.4mm wire;

[0057] Step 4: peeling the wire obtained in step 3 to obtain a heavy rare earth magnesium alloy wire with a diameter of 1.2 mm for arc additive manufacturing;

[0058] Step 5: Wind the wire obtained in step 4 to obtain a finished wire reel with a reel diameter of 400 mm. The wire meets the requirements of the national standard "GB / T 41112-2021 Magnesium and Magnesium Alloy Welding Wire".

[0059] The mechanical properties of the prepared φ1.2mm heavy rare earth magnesium alloy wire were tested.

[0060] Comparative Example 1

[0061] The heavy rare earth magnesium alloy wire for arc additive manufacturing in this comparative example includes, by mass percentage, Gd6.0%, Y1.0%, Nd 0.2%, Zn 0.2%, Zr 0.1%, other impurities include Fe, Cu, Si, Ni, with a total content of 0.4%, and the balance is Mg.

[0062] The preparation method of the heavy rare earth magnesium alloy wire for arc additive manufacturing is consistent with that of Example 1, and the mechanical properties of the prepared φ1.2 mm heavy rare earth magnesium alloy wire are tested.

[0063] The alloy compositions of the heavy rare earth magnesium alloy wires for arc additive manufacturing prepared in Examples 1 to 4 and Comparative Example 1 are shown in Table 1.

[0064] The mechanical property test results of the heavy rare earth magnesium alloy wires for arc additive manufacturing prepared in Examples 1 to 4 and Comparative Example 1 are shown in Table 1.

[0065] Table 1 Mechanical properties test results of heavy rare earth magnesium alloy wires for arc additive manufacturing prepared in Examples 1 to 4 and Comparative Example 1.

[0066]

[0067] The mechanical properties of Examples 1 to 4 of the present invention are all better than those of the comparative examples. The results show that the technology of the present invention has significant performance improvements over the conventional production process. The heavy rare earth magnesium alloy wire product provided by the present invention has good strength and plasticity, and can meet the needs of continuous forming in arc additive manufacturing.

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A heavy rare earth magnesium alloy wire for arc additive manufacturing, characterized in that: Calculated by mass percentage, it includes Gd: 8.0-12.0%, Y: 2.0-5.0%, Nd: 0.5-2.0%, Zn: 0.5-2.0%, Zr: 0.2-0.5%, and the balance is Mg and inevitable impurities.

2. The heavy rare earth magnesium alloy wire for arc additive manufacturing according to claim 1, characterized in that: Calculated by mass percentage, it includes Gd: 8.0-9.0%, Y: 2-2.5%, Nd: 0.5-1.0%, Zn: 0.5-0.8%, Zr: 0.3-0.4%, and the balance is Mg and inevitable impurities.

3. The heavy rare earth magnesium alloy wire for arc additive manufacturing according to claim 1, characterized in that: Calculated by mass percentage, it includes Gd: 9.0-9.5%, Y: 2.5-3%, Nd: 1.0-1.2%, Zn: 0.8-1.0%, Zr: 0.3-0.4%, and the balance is Mg and inevitable impurities.

4. The heavy rare earth magnesium alloy wire for arc additive manufacturing according to claim 1, characterized in that: Calculated by mass percentage, it includes Gd: 9.5%, Y: 3.0%, Nd: 1.2%, Zn: 1.0%, Zr: 0.4%, and the balance is Mg and inevitable impurities.

5. The heavy rare earth magnesium alloy wire for arc additive manufacturing according to claim 1, characterized in that: Calculated by mass percentage, it includes Gd: 9.5%, Y: 3.0%, Nd: 1.2%, Zn: 1.0%, Zr: 0.4%, and the balance is Mg and inevitable impurities.

6. The method for preparing a heavy rare earth magnesium alloy wire for arc additive manufacturing according to any one of claims 1 to 5, comprising the following steps: Step 1, melting the alloy raw material under vacuum conditions and then casting to obtain an ingot; Step 2: homogenize the ingot obtained in step 1, turn it into φ80mm extrusion billet, place the extrusion billet and the mold in a furnace for at least 1 hour, and then extrude it to obtain φ5-6mm wire billet; Step 3, the wire blank obtained in step 2 is subjected to continuous multiple-pass hot drawing to obtain a φ1.4-1.6 mm wire, and the wire and the die are lubricated with graphite before drawing; Step 4: peeling the wire obtained in step 3 to obtain a heavy rare earth magnesium alloy wire with a diameter of 1.2 mm for arc additive manufacturing; Step 5, winding the wire obtained in step 4 to obtain a finished wire reel with a reel diameter of 400 mm.

7. The preparation method according to claim 6, characterized in that: The temperature of the homogenization treatment in step 2 is 500-520°C, and the holding time is 15-24h; the holding temperature and extrusion temperature in the furnace are 450-500°C, the extrusion speed is 5-10mm / s, and the extrusion ratio is 30:

1.

8. The preparation method according to claim 7, characterized in that: In step 3, the drawing temperature is 400-450° C., and the drawing speed is 1.5-3 m / min.

9. The preparation method according to claim 8, characterized in that: When drawing from φ6mm to φ3mm, the deformation per pass is ~15%, and 10 passes are required.

10. The preparation method according to claim 9, characterized in that: When drawing from φ3mm to φ1.4mm, the deformation per pass is ~10%, and 15 passes are required.

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