High-toughness silicon carbide reinforced ZL114A aluminum alloy and preparation method thereof

Abstract

The invention discloses a high-toughness silicon carbide reinforced ZL114A aluminum alloy and a preparation method thereof, and belongs to the technical field of metal materials. The invention aims to solve the problem that the existing ZL114A aluminum alloy cannot have high strength and high toughness at the same time. The aluminum alloy is composed of Si, Mg, Ti, Sb, SiC and the balance Al. The method comprises the following steps: 1, weighing; 2, preparing Al (SiC) intermediate alloy prefabricated powder; 3, casting; and 4, solid solution, multidirectional forging and aging processes. The invention is used for the high-strength and high-toughness silicon carbide reinforced ZL114A aluminum alloy and the preparation method thereof.

Description

Technical Field

[0001] The invention belongs to the technical field of metal materials. Background Art

[0002] ZL114A aluminum alloy is widely used in many fields such as automobile, aerospace, thermal energy management, infrastructure construction, etc. due to its excellent casting properties, good mechanical properties and excellent corrosion resistance. It is particularly suitable for manufacturing complex shapes and lightweight parts. Its excellent casting characteristics make ZL114A perform well in castings with high strength requirements, but the matrix strength and hardness of the alloy are relatively low, and the toughness of the alloy is greatly reduced while the alloy strength is improved, which limits its application in more harsh environments. Therefore, improving the strength and toughness of ZL114A aluminum alloy has become the key to its application expansion. In recent years, the strategy of aluminum alloy nanoparticle reinforcement has become a hot topic in materials science research due to its advantages such as simple preparation process and significant improvement in material properties. By introducing particles, a ceramic reinforcement with excellent performance, the strength and hardness of aluminum alloy materials can be significantly improved to meet the needs of high-end application fields. The high modulus, high hardness, high melting point and low thermal expansion coefficient of SiC particles make them an ideal reinforcement phase for aluminum alloys, especially for applications in high mechanical load environments. At present, SiC particles have become one of the preferred reinforcement agents for particle-reinforced aluminum alloys due to their stable composite structure and good reinforcement effect. In the known ZL114A aluminum alloy material preparation technology, there is no report on the preparation method of using nano-scale SiC as reinforcing particles to achieve high-strength and toughness ZL114A aluminum alloy material. Summary of the invention

[0003] The present invention aims to solve the problem that the existing ZL114A aluminum alloy cannot have both high strength and high toughness, and further provides a high-strength and toughness silicon carbide reinforced ZL114A aluminum alloy and a preparation method thereof.

[0004] A high-strength and tough silicon carbide reinforced ZL114A aluminum alloy consists of 7.0% to 7.5% Si, 0.45% to 0.75% Mg, 0.1% to 0.20% Ti, 0.10% to 0.50% Sb, 0.05% to 0.15% SiC and the balance Al in terms of mass percentage.

[0005] A method for preparing high-strength and tough silicon carbide reinforced ZL114A aluminum alloy is carried out according to the following steps:

[0006] 1. Weighing:

[0007] AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSb10 modifier, nano SiC powder, aluminum ingot and aluminum powder are weighed as raw materials according to the mass percentage of 7.0% to 7.5% Si, 0.45% to 0.75% Mg, 0.1% to 0.20% Ti, 0.10% to 0.50% Sb, 0.05% to 0.15% SiC and the balance Al;

[0008] The mass ratio of the aluminum powder to the nano-SiC powder is 10:(1-2);

[0009] 2. Preparation of Al(SiC) master alloy preform powder:

[0010] The aluminum powder and the nano-SiC powder are ball-milled and mixed to obtain an Al(SiC) master alloy preformed powder;

[0011] 3. Melting and Casting:

[0012] AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSb10 modifier and aluminum ingot are melted and mixed to obtain alloy liquid, the alloy liquid is refined and skimmed, and then Al(SiC) master alloy prefabricated powder is added to melt and mix to obtain alloy melt, the alloy melt is cooled and placed in a mold, and then naturally cooled to room temperature and demolded to obtain a casting;

[0013] 4. Solid solution, multi-directional forging and aging process:

[0014] The castings were subjected to solution treatment, water quenching to room temperature, multi-directional forging and secondary aging treatment in sequence to obtain high-strength and tough silicon carbide reinforced ZL114A aluminum alloy;

[0015] The secondary aging treatment is specifically to first keep the temperature at 140°C to 155°C for 8h to 10h, then take it out and air cool it to room temperature, then keep it at 170°C to 185°C for 10h to 12h, then take it out and air cool it to room temperature.

[0016] The beneficial effects of the present invention are:

[0017] The nano-SiC reinforced ZL114A aluminum alloy prepared by the present invention has a simple and feasible preparation process, the Si phase grains inside the aluminum alloy are fine and well dispersed, the SiC strengthening phase is fine and evenly distributed, and it has high strength and hardness while maintaining good toughness. The room temperature tensile strength of the aluminum alloy of the present invention is 330MPa-360MPa, the room temperature tensile elongation is 9%-11%, and the hardness is HV100-120. The aluminum alloy of the present invention has stable mechanical properties, high strength, good toughness, simple and feasible production process, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a metallographic photograph of the high-strength and tough silicon carbide reinforced ZL114A aluminum alloy prepared in Example 1;

[0019] Figure 2 This is a metallographic photograph of the high-strength and toughness silicon carbide reinforced ZL114A aluminum alloy prepared in Example 2. DETAILED DESCRIPTION

[0020] Specific implementation method 1: This implementation method is a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy, which is composed of 7.0% to 7.5% Si, 0.45% to 0.75% Mg, 0.1% to 0.20% Ti, 0.10% to 0.50% Sb, 0.05% to 0.15% SiC and the remainder Al in mass percentage.

[0021] The beneficial effects of this embodiment are:

[0022] The nano-SiC reinforced ZL114A aluminum alloy prepared in this embodiment has a simple and feasible preparation process, the Si phase grains inside the aluminum alloy are fine and well dispersed, the SiC strengthening phase is fine and evenly distributed, and it has high strength and hardness while maintaining good toughness. The room temperature tensile strength of the aluminum alloy described in this embodiment is 330MPa~360MPa, the room temperature tensile elongation is 9%~11%, and the hardness is HV100~120. The aluminum alloy described in this embodiment has stable mechanical properties, high strength, good toughness, simple and feasible production process, and reduces production costs.

[0023] Specific implementation method 2: This implementation method is a method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy, which is carried out according to the following steps:

[0024] 1. Weighing:

[0025] AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSb10 modifier, nano SiC powder, aluminum ingot and aluminum powder are weighed as raw materials according to the mass percentage of 7.0% to 7.5% Si, 0.45% to 0.75% Mg, 0.1% to 0.20% Ti, 0.10% to 0.50% Sb, 0.05% to 0.15% SiC and the balance Al;

[0026] The mass ratio of the aluminum powder to the nano-SiC powder is 10:(1-2);

[0027] 2. Preparation of Al(SiC) master alloy preform powder:

[0028] The aluminum powder and the nano-SiC powder are ball-milled and mixed to obtain an Al(SiC) master alloy preformed powder;

[0029] 3. Melting and Casting:

[0030] AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSb10 modifier and aluminum ingot are melted and mixed to obtain alloy liquid, the alloy liquid is refined and skimmed, and then Al(SiC) master alloy prefabricated powder is added to melt and mix to obtain alloy melt, the alloy melt is cooled and placed in a mold, and then naturally cooled to room temperature and demolded to obtain a casting;

[0031] 4. Solid solution, multi-directional forging and aging process:

[0032] The castings were subjected to solution treatment, water quenching to room temperature, multi-directional forging and secondary aging treatment in sequence to obtain high-strength and tough silicon carbide reinforced ZL114A aluminum alloy;

[0033] The secondary aging treatment is specifically to first keep the temperature at 140°C to 155°C for 8h to 10h, then take it out and air cool it to room temperature, then keep it at 170°C to 185°C for 10h to 12h, then take it out and air cool it to room temperature.

[0034] Specific implementation method 3: This implementation method is different from specific implementation method 2 in that the particle size of the nano-SiC powder in step 1 is 30nm-50nm, and the particle size of the aluminum powder in step 1 is 100μm-200μm. Others are the same as specific implementation method 2.

[0035] Specific embodiment 4: This embodiment is different from specific embodiment 2 or 3 in that: the ball milling mixing described in step 2 is specifically carried out according to the following steps: using stainless steel grinding balls, under the conditions of a ball-to-material mass ratio of 10:(1-3) and a rotation speed of 180r / min-220r / min, ball milling for 10h-20h; the stainless steel grinding balls are a mixture of grinding balls with a diameter of 6mm, grinding balls with a diameter of 4mm and grinding balls with a diameter of 2mm, and the mass ratio of grinding balls with a diameter of 6mm: grinding balls with a diameter of 4mm: grinding balls with a diameter of 2mm is 1:(2-4):(2-4). Others are the same as specific embodiment 2 or 3.

[0036] Specific embodiment 5: This embodiment is different from the specific embodiments 2 to 4 in that: in step 3, the aluminum ingot and the AlSi12 master alloy are heated and melted at a temperature of 700°C to 780°C, and then the AlTi10 master alloy and the AlSb10 modifier are added and melted, and after melting, the mixture is stirred for 2min to 5min at a temperature of 700°C to 780°C and a stirring speed of 100r / min to 150r / min, and finally, the Mg ingot is pressed into the melting pot with a bell jar at a temperature of 700°C to 780°C to obtain a molten alloy. The rest is the same as the specific embodiments 2 to 4.

[0037] Specific embodiment 6: This embodiment is different from specific embodiments 2 to 5 in that the refining and slag skimming described in step 3 are specifically carried out according to the following steps: at a temperature of 700°C to 780°C and a gas flow rate of 10L / min to 20L / min, an inert gas is introduced into the alloy liquid for refining for 5min to 15min, and then slag skimming is carried out. Others are the same as specific embodiments 2 to 5.

[0038] Specific embodiment 7: This embodiment differs from specific embodiments 2 to 6 in that: in step 3, the alloy liquid temperature is adjusted to 800°C to 850°C, and then the Al (SiC) master alloy preformed powder is added, and after melting, the bottom is stirred for 1min to 2min at a speed of 300r / min to 500r / min. The rest is the same as specific embodiments 2 to 6.

[0039] Specific embodiment 8: This embodiment differs from specific embodiments 2 to 7 in that in step 3, the alloy melt is cooled to 700°C to 750°C, then poured into a metal mold preheated to 150°C to 200°C, and naturally cooled to room temperature. The rest is the same as specific embodiments 2 to 7.

[0040] Specific embodiment 9: This embodiment is different from specific embodiments 2 to 8 in that the solution treatment in step 4 is carried out at a temperature of 540° C. to 560° C. for 15 to 20 hours. The rest is the same as specific embodiments 2 to 8.

[0041] Specific embodiment 10: This embodiment differs from specific embodiments 2 to 9 in that the multi-directional forging described in step 4 is to use an air hammer to repeatedly forge in three mutually perpendicular directions, the forging reduction in each direction is 30% to 35% of the maximum dimension direction, and the three axial directions are performed alternately and cycled 3 to 4 times. The rest is the same as specific embodiments 2 to 9.

[0042] The following examples are used to verify the beneficial effects of the present invention:

[0043] Embodiment 1:

[0044] A method for preparing high-strength and tough silicon carbide reinforced ZL114A aluminum alloy is carried out according to the following steps:

[0045] 1. Weighing:

[0046] AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSr10 modifier, nano SiC powder, aluminum ingot and aluminum powder are weighed as raw materials according to the mass percentage of 7.3% Si, 0.60% Mg, 0.2% Ti, 0.20% Sb, 0.10% SiC and the balance Al;

[0047] The mass ratio of the aluminum powder to the nano-SiC powder is 10:1;

[0048] 2. Preparation of Al(SiC) master alloy preform powder:

[0049] The aluminum powder and the nano-SiC powder are ball-milled and mixed to obtain an Al(SiC) master alloy preformed powder;

[0050] 3. Melting and Casting:

[0051] AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSr10 modifier and aluminum ingot are melted and mixed to obtain alloy liquid, the alloy liquid is refined and skimmed, and then Al(SiC) master alloy prefabricated powder is added to melt and mix to obtain alloy melt, the alloy melt is cooled and placed in a mold, and then naturally cooled to room temperature and demolded to obtain a casting;

[0052] 4. Solid solution, multi-directional forging and aging process:

[0053] The castings were subjected to solution treatment, water quenching to room temperature, multi-directional forging and secondary aging treatment in sequence to obtain high-strength and tough silicon carbide reinforced ZL114A aluminum alloy;

[0054] The secondary aging treatment is specifically to keep the temperature at 155°C for 10 hours, then take it out and air cool it to room temperature, then keep it at 185°C for 10 hours, then take it out and air cool it to room temperature.

[0055] The purity of the Mg ingot in step 1 is >99%; the purity of the aluminum ingot and aluminum powder in step 1 is >99%;

[0056] The average particle size of the nano-SiC powder described in step 1 is 40 nm, and the average particle size of the aluminum powder described in step 1 is 100 μm.

[0057] The ball milling mixing described in step 2 is specifically carried out according to the following steps: using stainless steel grinding balls, ball milling for 15 hours at a ball-to-material mass ratio of 10:1 and a rotation speed of 200r / min; the stainless steel grinding balls are a mixture of grinding balls with a diameter of 6mm, grinding balls with a diameter of 4mm and grinding balls with a diameter of 2mm, and the mass ratio of grinding balls with a diameter of 6mm: grinding balls with a diameter of 4mm: grinding balls with a diameter of 2mm is 1:2:2.

[0058] In step three, the aluminum ingot and the AlSi12 master alloy are cut into small pieces, and then loaded into a crucible melting furnace in turn. The aluminum ingot and the AlSi12 master alloy are heated and melted at a temperature of 780°C, and then the AlTi10 master alloy and the AlSb10 modifier are added and melted. After melting, the mixture is stirred for 2 minutes at a temperature of 780°C and a stirring speed of 100r / min. Finally, the Mg ingot is pressed into the melting furnace with a bell jar at a temperature of 780°C to obtain a molten alloy.

[0059] The refining and slag skimming described in step three are specifically carried out according to the following steps: under the conditions of a temperature of 720°C, a rotation speed of 300r / min and a gas flow rate of 10L / min, argon gas is introduced into the alloy liquid for refining for 10 minutes, and then slag skimming is carried out.

[0060] In step 3, the alloy liquid temperature is adjusted to 850° C., and then the Al(SiC) master alloy preformed powder is added. After melting, the mixture is stirred at the bottom at a rotation speed of 300 r / min for 2 minutes.

[0061] In step three, the alloy melt is cooled to 750°C, then poured into a steel metal mold preheated to 200°C, and naturally cooled to room temperature.

[0062] The solution treatment described in step 4 is specifically a solution treatment at a temperature of 540° C. for 15 hours.

[0063] The multi-directional forging described in step 4 is specifically to use an air hammer to repeatedly forge in three mutually perpendicular directions, the forging reduction in each direction is 30% of the maximum dimension direction, and the three axial directions are performed alternately and cycled three times.

[0064] According to the national standard GBT228.1-2021 for tensile testing of metal materials, the high-strength and toughness silicon carbide reinforced ZL114A aluminum alloy prepared in Example 1 was tested, and the room temperature tensile strength σb of the alloy was measured to be 350 MPa, the room temperature tensile Young's strength σ0.2 was 320 MPa, and the room temperature tensile elongation δ was 10.2%; the hardness was HV115.

[0065] Embodiment 2: This embodiment is different from Embodiment 1 in that: in step 1, 7.5% Si, 0.70% Mg, 0.2% Ti, 0.20% Sb, 0.15% SiC and the balance Al are weighed according to mass percentage. The rest is the same as Embodiment 1.

[0066] Figure 1 This is a metallographic photograph of the high-strength and tough silicon carbide reinforced ZL114A aluminum alloy prepared in Example 1; as can be seen from the figure, the alloy structure is dense, the internal Si phase grains are fine and well dispersed, and the SiC reinforcement phase is fine and evenly distributed.

[0067] Figure 2 This is a metallographic photograph of the high-strength and tough silicon carbide reinforced ZL114A aluminum alloy prepared in Example 2; as can be seen from the figure, the alloy structure is dense, the internal Si phase grains are fine and well dispersed, and the SiC reinforcement phase is fine and evenly distributed.

Claims

1. A high-strength and tough silicon carbide reinforced ZL114A aluminum alloy, characterized in that It consists of 7.0% to 7.5% Si, 0.45% to 0.75% Mg, 0.1% to 0.20% Ti, 0.10% to 0.50% Sb, 0.05% to 0.15% SiC and the balance Al in terms of mass percentage.

2. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy as claimed in claim 1, characterized in that It is carried out in the following steps:

1. Weighing: AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSb10 modifier, nano SiC powder, aluminum ingot and aluminum powder are weighed as raw materials according to the mass percentage of 7.0% to 7.5% Si, 0.45% to 0.75% Mg, 0.1% to 0.20% Ti, 0.10% to 0.50% Sb, 0.05% to 0.15% SiC and the balance Al; The mass ratio of the aluminum powder to the nano-SiC powder is 10:(1-2); 2. Preparation of Al(SiC) master alloy preform powder: The aluminum powder and the nano-SiC powder are ball-milled and mixed to obtain an Al(SiC) master alloy preformed powder; 3. Melting and Casting: AlSi12 master alloy, Mg ingot, AlTi10 master alloy, AlSb10 modifier and aluminum ingot are melted and mixed to obtain alloy liquid, the alloy liquid is refined and skimmed, and then Al(SiC) master alloy prefabricated powder is added to melt and mix to obtain alloy melt, the alloy melt is cooled and placed in a mold, and then naturally cooled to room temperature and demolded to obtain a casting; 4. Solid solution, multi-directional forging and aging process: The castings were subjected to solution treatment, water quenching to room temperature, multi-directional forging and secondary aging treatment in sequence to obtain high-strength and tough silicon carbide reinforced ZL114A aluminum alloy; The secondary aging treatment is specifically to first keep the temperature at 140°C to 155°C for 8h to 10h, then take it out and air cool it to room temperature, then keep it at 170°C to 185°C for 10h to 12h, then take it out and air cool it to room temperature.

3. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that The particle size of the nano-SiC powder described in step 1 is 30nm-50nm, and the particle size of the aluminum powder described in step 1 is 100μm-200μm.

4. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that The ball milling mixing described in step 2 is specifically carried out according to the following steps: using stainless steel grinding balls, at a ball-to-material mass ratio of 10:(1-3) and a rotation speed of 180r / min-220r / min, ball milling for 10h-20h; the stainless steel grinding balls are a mixture of grinding balls with a diameter of 6mm, grinding balls with a diameter of 4mm and grinding balls with a diameter of 2mm, and the mass ratio of grinding balls with a diameter of 6mm: grinding balls with a diameter of 4mm: grinding balls with a diameter of 2mm is 1:(2-4):(2-4).

5. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that In step three, the aluminum ingot and the AlSi12 master alloy are heated and melted at a temperature of 700°C to 780°C, and then the AlTi10 master alloy and the AlSb10 modifier are added and melted. After melting, they are stirred for 2min to 5min at a temperature of 700°C to 780°C and a stirring speed of 100r / min to 150r / min. Finally, at a temperature of 700°C to 780°C, the Mg ingot is pressed into the bell jar for melting to obtain an alloy liquid.

6. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that The refining and slag skimming described in step three are specifically carried out according to the following steps: at a temperature of 700°C to 780°C and a gas flow rate of 10L / min to 20L / min, an inert gas is introduced into the alloy liquid for refining for 5min to 15min, and then the slag is skimmed.

7. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that In step 3, the alloy liquid temperature is adjusted to 800° C. to 850° C., and then the Al(SiC) intermediate alloy preformed powder is added. After melting, the mixture is stirred at the bottom for 1 min to 2 min at a rotation speed of 300 r / min to 500 r / min.

8. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that In step three, the alloy melt is cooled to 700°C to 750°C, then poured into a metal mold preheated to 150°C to 200°C, and naturally cooled to room temperature.

9. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that The solution treatment described in step 4 is specifically carried out at a temperature of 540°C to 560°C and kept warm for 15h to 20h.

10. The method for preparing a high-strength and tough silicon carbide reinforced ZL114A aluminum alloy according to claim 2, characterized in that The multi-directional forging described in step 4 is specifically to use an air hammer to repeatedly forge in three mutually perpendicular directions, the forging reduction in each direction is 30% to 35% of the maximum dimension direction, and the three axial directions are performed alternately and cycled 3 to 4 times.

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