Method for improving product of strength and ductility of rare earth Y modified ADC12 regenerated aluminum alloy

Abstract

The invention belongs to the technical field of non-ferrous metal processing, and particularly relates to a method for improving the product of strength and ductility of a rare earth Y modified ADC12 regenerated aluminum alloy, the rare earth Y modified ADC12 regenerated aluminum alloy is heated to a first temperature at a certain heating rate, heat preservation is performed for a first time, then the rare earth Y modified ADC12 regenerated aluminum alloy is put into water to be quenched for 10-20 s, and the water temperature ranges from 0 DEG C to 10 DEG C. By adopting the quenching temperature of 0-10 DEG C, the eutectic Si phase and the alpha-Fe phase in the alloy can have a better refining effect, especially the spheroidizing effect of the eutectic Si phase is more remarkable, the matrix splitting effect of the eutectic Si phase and the alpha-Fe phase is weakened, and the tensile strength of the alloy is better improved. The product of strength and elongation as the product of tensile strength and elongation can better reflect the comprehensive mechanical properties of the material, and experiments show that when the quenching temperature is 0-10 DEG C, the product of strength and elongation of the material can reach 4.1 GPa% or above, and the material has excellent comprehensive strength and toughness level.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal processing, and in particular relates to a method for improving the strength-plasticity product of rare earth Y-modified ADC12 recycled aluminum alloy. Background Art

[0002] The commercial die-casting aluminum alloy JIS (Japanese Industrial Standard) ADC12 modified with rare earth Y is an Al-Si-Cu series secondary aluminum alloy, which belongs to a type of casting aluminum alloy. This alloy has the advantages of excellent casting performance, light weight and easy recycling and reuse, and is widely recognized in industrial production. However, for recycled secondary aluminum alloys, their mechanical properties are often affected by the morphology of the inclusion phase in the matrix. The coarse α-Fe phase and flaky eutectic Si phase in the alloy will seriously split the matrix, thereby affecting its mechanical properties, especially poor plasticity, easy brittle fracture, and inability to undergo large deformation, which greatly limits its scope of application.

[0003] Therefore, in order to improve the mechanical properties of the cast rare earth Y modified ADC12 recycled aluminum alloy, effective methods must be taken to optimize the alloy structure. T6 heat treatment is the most commonly used heat treatment process for aluminum-silicon alloys. It can make the Al2Cu phase and the eutectic Si phase solid dissolve in the α-Al phase, effectively strengthen the matrix α-Al phase, and refine the α-Fe phase and the blocky primary Si phase, thereby improving the various mechanical properties of the rare earth Y modified ADC12 recycled aluminum alloy. However, although the T6 heat treatment can improve the plasticity of the rare earth Y modified ADC12 recycled aluminum alloy to a certain extent, its strength-ductility product is low, indicating that the T6 heat treatment cannot effectively improve the comprehensive strength and toughness level of the rare earth Y modified ADC12 recycled aluminum alloy. Summary of the invention

[0004] Based on this, the present application provides a method for improving the tensile properties of centrifugally cast rare earth Y-modified ADC12 recycled aluminum alloy, so as to solve the technical problem that the strength-plasticity product of the rare earth Y-modified ADC12 recycled aluminum alloy after T6 heat treatment in the prior art is low and the comprehensive strength and toughness level of the rare earth Y-modified ADC12 recycled aluminum alloy cannot be effectively improved.

[0005] The technical solution of this application to solve the above technical problems is as follows:

[0006] A method for improving the strength-plasticity product of rare earth Y-modified ADC12 recycled aluminum alloy comprises the following steps:

[0007] Solution treatment: the rare earth Y-modified ADC12 recycled aluminum alloy is heated to a first temperature at a certain heating rate and kept warm for a first time, and then placed in water for quenching for 10 to 20 seconds, wherein the water temperature is 0°C to 10°C.

[0008] Preferably, in the above method, the water temperature is 0°C to 5°C.

[0009] Preferably, in the above method, the heating rate is 8 to 15° C. / min, the first temperature is 400 to 600° C., and the first time length is 5 to 10 h.

[0010] Preferably, in the above method, after the solution treatment, the method further comprises:

[0011] Aging treatment: put the quenched rare earth Y modified ADC12 recycled aluminum alloy into a high temperature drying oven within 5 minutes and keep it at the second temperature for the second time.

[0012] Preferably, in the above method, the second temperature is 150 to 200° C., and the second time period is 7 to 12 hours.

[0013] Preferably, in the above method, before the solid solution treatment, it also includes: adding 0.05 to 0.15wt% of rare earth Y to the ADC12 recycled aluminum alloy, and obtaining the rare earth Y-modified ADC12 recycled aluminum alloy after centrifugal casting.

[0014] The present invention adopts the above technical solution, and its beneficial effects are:

[0015] The method for improving the strength-ductility product of rare earth Y-modified ADC12 recycled aluminum alloy provided by the present invention is to heat the rare earth Y-modified ADC12 recycled aluminum alloy to a first temperature at a certain heating rate and keep it warm for a first time, and then put it into water for quenching for 10 to 20 seconds, wherein the water temperature is 0°C to 10°C. The use of a quenching temperature of 0°C to 10°C can make the eutectic Si phase and α-Fe phase in the alloy have a better refinement effect, especially the spheroidization effect of the eutectic Si phase is more significant, and the effect of the eutectic Si phase and the α-Fe phase splitting the matrix is ​​weakened, thereby better improving the tensile strength of the alloy. The strength-ductility product, as the product of tensile strength and elongation, can better reflect the comprehensive mechanical properties of the material. Experiments show that when the quenching temperature is between 0°C and 10°C, the strength-ductility product of the material can reach more than 4.1GPa%, and has an excellent comprehensive strength and toughness level. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Metallographic microstructure of rare earth Y modified ADC12 recycled aluminum alloy samples at different quenching temperatures.

[0017] Figure 2 Mechanical properties of rare earth Y modified ADC12 recycled aluminum alloy samples at different quenching temperatures. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other. The technical solution of the present invention will be further described below in conjunction with the drawings of the embodiments of the present invention, and the present invention is not limited to the following specific implementation methods.

[0019] In a specific embodiment of the present invention, a method for improving the strength-ductility product of rare earth Y-modified ADC12 recycled aluminum alloy comprises the following steps:

[0020] Solution treatment: the rare earth Y-modified ADC12 recycled aluminum alloy is heated to a first temperature at a certain heating rate and kept warm for a first time, and then placed in water for quenching for 10 to 20 seconds, wherein the water temperature is 0°C to 10°C.

[0021] T6 heat treatment is divided into solution treatment and aging treatment. In the solution treatment, the alloy material is first heated to a high temperature and kept warm for a certain period of time, so that the soluble elements in the impurity phase, such as magnesium and silicon, are dissolved in the matrix; then the solute elements in the solid solution are quenched so that they do not have time to precipitate, forming a supersaturated solid solution with higher hardness and strength. This supersaturated solid solution also has good ductility and toughness. T6 heat treatment improves the strength and hardness of the alloy by solid solution strengthening of Si in rare earth Y-modified ADC12 recycled aluminum alloy and precipitation of Si particles to increase the content of hard phase in the alloy. The precipitation of Si particles can effectively hinder the movement of grain boundaries, increase the alloy's deformation resistance and fatigue resistance, and the distribution of hard phase particles can effectively hinder the movement of dislocations, thereby improving the tensile strength and hardness of the alloy.

[0022] Quenching is an important step in the T6 heat treatment process, and its role is to increase the hardness and strength of the material by rapid cooling. In addition, quenching can also refine the grains of the material, improve the strengthening effect of the grain interface, and increase the plasticity and toughness of the material. Quenching plays a key role in T6 heat treatment. Different quenching temperatures are used in T6 heat treatment, and the effect of solid solution strengthening is different. Selecting a suitable quenching temperature can make the eutectic Si phase and α-Fe phase in the alloy have a better refinement effect, especially the spheroidization effect of the eutectic Si phase is more significant, and the eutectic Si phase and α-Fe phase split the matrix. The effect is weakened, and the tensile strength of the alloy is better improved. In this application, the quenching medium is water, and the temperature is 0°C to 10°C. Experiments show that at this quenching temperature, the eutectic Si phase of the rare earth Y modified ADC12 recycled aluminum alloy has the best refinement and spheroidization effect, the size is significantly reduced, and the spheroidization is more obvious; the α-Fe phase has the best refinement effect, and it mostly presents a small irregular polygonal shape. The material strength-plastic product can reach more than 4.1GPa%, and has an excellent comprehensive strength and toughness level. Furthermore, the quenching temperature is 0°C to 5°C.

[0023] In a specific embodiment of the present application, the heating rate is 8 to 15° C. / min, the first temperature is 400 to 600° C., and the first time length is 5 to 10 h.

[0024] In another specific embodiment of the present application, the solution treatment further includes: aging treatment: placing the quenched rare earth Y-modified ADC12 recycled aluminum alloy in a high-temperature drying oven within 5 minutes, and keeping it at a second temperature for a second time. Wherein, the second temperature is 150 to 200°C, and the second time is 7 to 12 hours. The aging treatment in this application is artificial aging, which can rearrange the atoms inside the rare earth Y-modified ADC12 recycled aluminum alloy and further improve the mechanical properties of the material.

[0025] In another specific embodiment of the present application, the solution treatment further includes: adding 0.05 to 0.15wt% of rare earth Y to the ADC12 recycled aluminum alloy, and obtaining the rare earth Y-modified ADC12 recycled aluminum alloy after centrifugal casting. The addition of rare earth Y can help improve the thermal stability and corrosion resistance of the ADC12 recycled aluminum alloy, so that the material performs better in high temperature and corrosive environments.

[0026] It is worth noting that the process temperature and process time involved in the above-mentioned embodiments are all temperatures or times used in the experimental process. Those skilled in the art can make reasonable adjustments within the error range based on the process temperature and process time provided by the present invention, which should be included in the protection scope of the present invention.

[0027] The technical solution and technical effects of the present invention are further illustrated below through specific experimental examples.

[0028] 1. Experimental Materials

[0029] The rare earth Y-modified ADC12 recycled aluminum alloy is obtained by centrifugal casting of 0.1wt% rare earth Y-modified ADC12 recycled aluminum alloy, wherein the ADC12 recycled aluminum alloy is a new die-casting Al-Si alloy, which is made by recycling and regenerating waste aluminum alloy, and its chemical composition is shown in Table 1.

[0030] Table 1 Main chemical composition of ADC12 recycled aluminum alloy

[0031]

[0032] 2. Comparative Example

[0033] Unheat-treated rare earth Y-modified ADC12 recycled aluminum alloy sample.

[0034] 3. Experimental examples

[0035] The rare earth Y modified ADC12 recycled aluminum alloy sample was heated to 500°C at a heating rate of 10°C / min and kept warm for 7 hours, then quenched in water for 15 seconds, where the water temperatures were 0°C, 10°C, 30°C, 60°C, 80°C and boiling (the experimental location was Yinchuan, with an altitude of 1010m, and the measured boiling point of water was 97°C); after quenching, it was placed in a high-temperature drying oven at 170°C for artificial aging within 5 minutes and kept warm for 10 hours.

[0036] 4. Experimental results analysis

[0037] According to the "GB / T228.1-2010 Metal Material Tensile Test Standard", the tensile test was carried out to test the tensile strength and other mechanical properties of the samples. Figure 1 and Figure 2 .

[0038] See also Figure 1 The metallographic structure of the original sample of rare earth Y modified ADC12 recycled aluminum alloy is as follows: Figure 1 (a) As shown in the figure. It can be seen that the α-Al phase in the ADC12 recycled aluminum alloy without T6 heat treatment is a large area of ​​irregular white phase, and its phase outline is unclear and irregularly distributed. The dark black structure with irregular block shape and large area is the primary Si phase. After heat treatment, the primary Si phase almost disappears, and the precipitated dark black structure is the eutectic Si phase; the dark black structure with strip or fiber shape and irregular arrangement is the eutectic Si phase; the light black structure is the α-Fe phase, which is irregular block or flake, and the morphology of the Si phase and the α-Fe phase will significantly affect the mechanical properties of the material.

[0039] Depend on Figure 1 (b) It can be seen that when the quenching temperature is 0℃, the eutectic Si phase has the best refinement and spheroidization effect, the size is significantly reduced, and the spheroidization is more obvious; the α-Fe phase has the best refinement effect, mostly presenting small irregular polygonal shapes. Figure 1 (c) It can be seen that when the quenching temperature is 10°C, short rod-shaped eutectic Si phase begins to appear, and the overall size tends to increase; at this time, the α-Fe phase is mostly small fishbone or Chinese character shapes, mixed with a small amount of irregular polygonal shapes. Figure 1 (d) It can be seen that when the quenching temperature is 30°C, the spheroidization effect of the eutectic Si phase begins to decline significantly, larger blocks of eutectic Si phase begin to appear, and the number of rod-shaped eutectic Si phases increases; at this time, the α-Fe phase is mostly small fishbone or Chinese character shapes. Figure 1 (e) It can be seen that when the quenching temperature is 60℃, the spheroidization and refinement effects of the eutectic Si phase are the worst, and most of them are blocky and long rod-shaped, and the distribution is also relatively uneven; at this time, the α-Fe phase is mostly small fishbone or Chinese character shapes, mixed with a small amount of irregular polygonal shapes. Figure 1(f) It can be seen that when the quenching temperature is 80℃, the precipitation of eutectic Si phase increases, but the spheroidization effect of eutectic Si phase is improved, and the large eutectic Si phase increases further; at this time, the α-Fe phase is mostly irregular polygonal, mixed with a small amount of fine fishbone or Chinese character shapes. Figure 1 (g) It can be seen that when the quenching temperature is boiling, the number of eutectic Si phase precipitations increases significantly, most of which are spherical in shape with different sizes and are distributed more evenly.

[0040] See also Figure 2 , tensile strength and elongation of rare earth Y modified ADC12 recycled aluminum alloy samples at different quenching temperatures. As can be seen from the figure, with the increase of quenching temperature, the tensile strength of the alloy continues to decrease, reaching the highest at 0℃, which corresponds to the changing trend of the solid solution and refinement degree of the eutectic Si phase in the metallographic structure; the elongation of the alloy first decreases and then increases, reaching the best at the quenching temperature of 0℃, corresponding to the change of the spheroidization degree of the eutectic Si phase. The strength-ductility product, as the product of tensile strength and elongation, can better reflect the comprehensive mechanical properties of the material. The strength-ductility product of the material reaches the best when the quenching temperature is 0℃.

[0041] In summary, the present application scheme quenches the rare earth Y-modified ADC12 recycled aluminum alloy in water at 0°C to 10°C, and the strength-plasticity product can reach more than 4.1GPa%, with excellent comprehensive strength and toughness level. It can be widely used in transportation, daily packaging, aerospace and other fields, especially in automobile manufacturing, and is used to manufacture gearbox parts, wheel covers, body structural parts, engine cylinders, etc.

[0042] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for improving the strength-plasticity product of rare earth Y-modified ADC12 recycled aluminum alloy, characterized in that: The following steps are involved: Solution treatment: the rare earth Y-modified ADC12 recycled aluminum alloy is heated to a first temperature at a certain heating rate and kept warm for a first time, and then placed in water for quenching for 10 to 20 seconds, wherein the water temperature is 0°C to 10°C.

2. The method according to claim 1, characterized in that The water temperature is 0°C to 5°C.

3. The method according to claim 1, characterized in that The heating rate is 8 to 15° C. / min, the first temperature is 400 to 600° C., and the first time is 5 to 10 h.

4. The method according to claim 1, characterized in that: The solution treatment further comprises: Aging treatment: put the quenched rare earth Y modified ADC12 recycled aluminum alloy into a high temperature drying oven within 5 minutes and keep it at the second temperature for the second time.

5. The method according to claim 4, characterized in that The second temperature is 150 to 200° C., and the second time period is 7 to 12 hours.

6. The method according to claim 1, characterized in that Before the solid solution treatment, the method also includes: adding 0.05 to 0.15wt% of rare earth Y into the ADC12 recycled aluminum alloy, and obtaining the rare earth Y-modified ADC12 recycled aluminum alloy after centrifugal casting.

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