High strength and toughness die-cast aluminum silicon alloy reinforced by non-heat treatment and its manufacturing method

Abstract

The present invention provides a non-heat-treated high strength and toughness die-casting aluminum silicon alloy and its manufacturing method, in which the weight percentages of the components are Si 8.0-10.0wt.%, Mg 0.1-0.5wt.%, Mn 0.5-0.8wt.%, Cu 0.05-0.5wt.%, Ti 0.05-0.2wt.%, Sr 0.01-0.05wt.%, V 0.01-0.1wt.%, RE 0.01-0.15wt.%, Fe < 0.2wt.%, the total amount of other impurities ≦ 0.4%, the balance being Al. Sr can be used to refine eutectic silicon, and V and RE elements can be added during the manufacturing process to significantly refine the eutectic silicon structure. When the alloy contains a relatively high Si content, it can obtain high strength and toughness properties, so that the large body structural components can meet the fluidity, strength and plasticity requirements of die-cast aluminum alloy materials.

Description

[Technical field]

[0001] The present invention relates to the field of metal materials technology, in particular to a non-thermal-treated strengthened high-strength and high-toughness die-casting aluminum-silicon alloy and a manufacturing method thereof. [Background technology]

[0002] Under the "double carbon" goal, the country's requirements for environmental protection are increasing. With the release of the "energy-saving and new energy vehicle technology roadmap", the lightweighting of new energy vehicles has become a development direction that has attracted great attention. Aluminum alloy, as a common metal structural material for the car body, has low density, high specific strength, and excellent vibration control effect. It is used in automobile vibration control towers, automobile rear side members and other components, and has obvious advantages in lightweighting, good strength and rigidity, and high fatigue resistance. Integrated design and integrated die-casting molding are favorable for reducing the processing process and reducing repeated pollution to the environment, while at the same time allowing the design of the casting structure to be flexible and meet the requirements of different products.

[0003] The body structural components of new energy vehicles generally use die-cast aluminum alloys, mainly heat-treated high-strength and high-toughness die-cast aluminum alloy materials represented by Silafont-36 alloy (US Patent No. 6,364,970). This material adopts "high vacuum die-casting + heat treatment" to make the casting achieve a yield strength of 100-120MPa, a tensile strength of 180-220MPa, and an elongation rate of 10-15%. However, for thin-walled die-cast castings, the use of this technology has two disadvantages: (1) high vacuum die-casting significantly increases the process difficulty and production costs; (2) the use of heat treatment process causes a certain amount of deformation and bubbles in the casting, which affects the product's yield rate and increases the cost. Therefore, research institutes in various countries have been actively developing non-heat-treated high-strength and high-toughness die-cast aluminum alloy materials, which can be applied to the mass production of large and complex die-cast structural components. In particular, new energy automobile manufacturers such as Tesla use non-heat-treated alloys to manufacture large integrated vehicle body structural components, and the alloy main component used is Al7SiMgMn alloy (US Patent Application Publication No. 2005 / 0167012). This alloy cooperates with high vacuum and even ultra-high vacuum die casting to manufacture parts, and this technological route can be adopted to alleviate the part deformation problem caused by traditional heat-treated alloys. However, there are two main problems: (1) The Si content in the alloy is relatively low (~7wt.%), which can improve the elongation rate of the material to 10-15%. However, the low Si content limits the fluidity of the non-heat-treated alloy, and there is a risk of underfilling of large castings. (2) The alloy strength of the traditional Al7SiMgMn alloy is relatively low (typical yield strength 110-120MPa, tensile strength 180-220MPa), and the large casting has a relatively large overall thickness and a relatively large number of thick-walled areas in the structural design. Therefore, while the material elongation rate is not changed or is slightly reduced (ensuring elongation rate > 10% and meeting the rivet requirements of the body structural members), the Si content in the alloy can be increased to improve the material fluidity and at the same time improve the material strength, which is of great significance to the optimization of large body casting structures.

[0004] Therefore, a non-heat-treated die-cast aluminum silicon alloy with high strength and toughness is developed, and its manufacturing and die-casting process are studied to meet the practical requirements of high-quality and high-performance aluminum alloy die-cast parts that are constantly improving in the automotive industry, and become one of the goals desired by the die-casting field. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 6,364,970 [Patent Document 2] US Patent Application Publication No. 2005 / 0167012 Summary of the Invention [Problem to be solved by the invention]

[0006] In the background of the above-mentioned prior art, the object of the present invention is to provide a non-heat-treated strengthened high-strength and high-toughness die-casting aluminum silicon alloy and its manufacturing method. On the premise of ensuring that the alloy has good casting performance, the non-heat-treated casting has excellent comprehensive mechanical performance, thereby meeting the performance requirements of vehicle body structural members, especially large and thin-walled vehicle body structural members. [Means for solving the problem]

[0007] To achieve this objective, the present invention has found in the long-term study of die-casting aluminum alloys that the Si content in die-casting aluminum silicon alloys has a significant effect on the casting performance, strength and plasticity of the alloy. In general, as the Si content increases, the strength of the alloy increases, the fluidity increases and the plasticity decreases. The Sr element has a transforming and refining effect on the eutectic Si in the alloy, but as the Si content increases, the plasticity tends to decrease, making it difficult to achieve 10% plasticity. The present invention is mainly intended to solve the problem that the plasticity of Al-Si alloys decreases under die-casting conditions after the Si content increases. With the increase in the Si content in the alloy, the eutectic Si content in the structure increases, and the size and shape of the eutectic Si also change accordingly, and become an important factor affecting the plasticity of the alloy. In order to solve the decrease in material plasticity caused by the increase in the Si content in the alloy, the present invention creatively introduces the V element to refine the eutectic Si, thereby obtaining a fine eutectic Si structure. In addition, a large amount of experimental verification in the previous period has found that rare earth elements such as La, Er, Ce, etc. in rare earth elements act in combination with V element to further refine the eutectic Si structure in the alloy, thereby changing the size and shape of the eutectic Si. The combined addition of V + RE generates fine eutectic Si particles in the as-cast structure, thereby ensuring that die-cast aluminum alloy materials with high Si content still have high plasticity. Meanwhile, the more Si is added, the better the strength and fluidity of the alloy becomes. Meanwhile, the combined addition of V + RE keeps the eutectic Si in a finely dispersed state, improving the plasticity of the alloy. Furthermore, under the premise of ensuring excellent casting performance, the present invention can greatly improve the mechanical performance of die-cast aluminum silicon alloy, and obtain the comprehensive mechanical performance of high strength and high toughness that is compatible with strength and formability. Thus, the object of the present invention is achieved by the following technical solutions: The present invention provides a high strength and high toughness die-casting aluminum silicon alloy strengthened by non-heat treatment, in which the weight percentages of the respective components in the die-casting aluminum silicon alloy are: Si 8.0-10.0wt.%, Mg 0.1-0.5wt.%, Mn 0.5-0.8wt.%, Cu 0.05-0.5wt.%, Ti 0.05-0.2wt.%, Sr 0.01-0.05wt.%, V 0.01-0.1wt.%, RE 0.01-0.15wt.%, Fe < 0.2wt.%, and the total amount of other impurities is ≦ 0.4wt.%, with the balance being Al. In one embodiment of the present invention, the aforementioned RE elements include one or more of La, Ce, and Er elements.

[0008] The present invention further relates to a method for producing a non-thermally strengthened high strength and high toughness die-casting aluminum silicon alloy, said method comprising the steps of: S1, Drying: The prepared raw materials, pure Al, pure Si, pure Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Cu intermediate alloy, Al-RE intermediate alloy, and Al-V intermediate alloy, are preheated and dried. S2, Smelting: After melting pure Al in the first heating, add Al-Ti intermediate alloy, Al-Cu intermediate alloy, Al-Mn intermediate alloy, Al-V intermediate alloy, and pure Si, and lower the temperature after the intermediate alloys have melted. Pure Mg is pressed into the bottom of the melt and melted, and after it has completely melted, the alloy melt is refined by heating it a second time. Furthermore, an Al-RE intermediate alloy is pressed into the bottom of the melt and melted, and after it has completely melted, it is left to stand, thereby obtaining a high-strength, high-toughness die-cast aluminum silicon alloy that has been strengthened without heat treatment.

[0009] In one embodiment of the present invention, the preheating temperature in step S1 is 190 to 210°C. As one embodiment of the present invention, the temperature of the initial heating in step S2 is 750°C to 760°C. In one embodiment of the present invention, the temperature is decreased to 680°C to 700°C in step S2. As an embodiment of the present invention, in step S2, pure Mg, Al-RE intermediate alloy is injected into the melt and then stirred for 3 to 5 minutes to completely melt it. In one embodiment of the present invention, the temperature of the second heating in step S2 is 720 to 730° C. RE is an alteration element, and is added last in the smelting process of the aluminum alloy. In one embodiment of the present invention, the refining in step S2 is specifically as follows: A rotary spraying device is used to flow nitrogen gas containing refining agent powder into the molten material to perform powder spraying refining, slag removal, and gas removal treatment, followed by leaving the material to stand for 10 to 15 minutes to complete the slag removal treatment, and obtain the molten material after refining. In one embodiment of the present invention, the process parameters of the rotary spraying device are: gas removal rotation speed 300-350 r / min, gas removal time 5-10 min, gas source pressure during gas removal 0.35±0.05 MPa, and gas flow rate 0.2-0.8 sccm. In one embodiment of the present invention, the refining agent used includes one of magnesium chloride and calcium chloride, and the amount of the refining agent added is 0.2-0.5% of the molten material weight. In one embodiment of the present invention, the standing time in step S2 is 10 to 15 minutes. In one embodiment of the present invention, the non-thermal treatment strengthened high strength and high toughness die-casting aluminum silicon alloy in step S2 is an alloy ingot which is cast or poured and then further die-cast. In one embodiment of the present invention, the casting temperature is 690 to 710°C. As an embodiment of the present invention, the specific parameters of the above-mentioned die casting molding are as follows: the injection speed is 3-6 m / s, the ratio of the release agent to water is 1:80-1:120, the mold temperature is 200-250°C, and the casting pressure is 30-100 MPa. Effect of the Invention

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. The high-strength die-casting aluminum silicon alloy strengthened by non-heat treatment produced by the present invention has important industrial application value. Under die-casting conditions, the die-casting aluminum silicon alloy has excellent performance such as yield strength of 120-160MPa, tensile strength of 260-320MPa, and elongation of 10-15% (AlSi10MnMg alloy, as-cast tensile strength of 200-220MPa, elongation of 5-8%). It also has good die-casting performance, which greatly meets the application demand of large thin-walled car body structural parts in the automobile industry. 2. The alloy achieves excellent performance in the as-cast state, with a yield strength of 120-160MPa, a tensile strength of 260-320MPa, and an elongation of 10-15%. Compared with conventional heat-treatable alloys, it reduces the number of heat treatment processes for parts, thereby improving the yield rate of castings and reducing the cost of castings. [Brief description of the drawings]

[0011] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the drawings, in which: [Figure 1] Schematic diagrams of SEM microstructure observation of castings of Examples and Comparative Examples. a shows a schematic diagram of SEM microstructure observation of A1 casting. b shows a schematic diagram of SEM microstructure observation of A2 casting. c shows a schematic diagram of SEM microstructure observation of A3 casting. d shows a schematic diagram of SEM microstructure observation of A4 casting. e shows a schematic diagram of SEM microstructure observation of A5 casting. f shows a schematic diagram of SEM microstructure observation of A6 casting. g shows a schematic diagram of SEM microstructure observation of A7 casting. h shows a schematic diagram of SEM microstructure observation of A8 casting. i shows a schematic diagram of SEM microstructure observation of A9 casting. j shows a schematic diagram of SEM microstructure observation of A10 casting. k shows a schematic diagram of SEM microstructure observation of A11 casting. l shows a schematic diagram of SEM microstructure observation of A12 casting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following, in order to facilitate understanding of the advantages and features of the present invention by those skilled in the art, the high-toughness die-casting aluminum-silicon alloy strengthened by non-heat treatment and its manufacturing method provided by the present invention will be further described with examples, without limiting the scope of application of the present invention.

[0013] Example 1 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 8.0 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.02 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0014] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and dried. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloys are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, smelting agent powder of 0.4% of the total weight of the melt is introduced, and the melt is aerated for 10 minutes at 300r / min and a gas flow rate of 0.5sccm to remove slag and remove gas. It is then left to stand for 12 minutes to complete the slag removal process and perform on-site rapid composition analysis testing. After the composition passes the test, it is subjected to high pressure casting at 690°C. The injection speed was 3 m / s, the casting pressure was 80 MPa, the release agent (the release agent is a solvent and needs to be diluted with water when used, here the ratio of release agent to water is shown) ratio was 1:100, and the mold temperature was 230°C. The mold used in the production process was a die-casting test bar mold, and the obtained casting is designated as A1.

[0015] Example 2 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 8.0 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, Er: 0.05 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0016] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, i.e. pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, and Al-10Er intermediate alloy, are preheated to 200°C and dried. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, pure Si alloy are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10Er intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is designated A2.

[0017] Example 3 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 8.0 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.02 wt.%, Er: 0.05 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0018] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Er intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloy are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10Er intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is designated A3.

[0019] Example 4 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 9.5 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.02 wt.%, Er: 0.05 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0020] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Er intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloy are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10Er intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is labeled A4.

[0021] Example 5 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 9.5 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.02 wt.%, La: 0.05 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0022] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10La intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 720°C to melt pure aluminum, then heated to 755°C to add Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, and pure Si alloys. After the intermediate alloy is melted, the furnace is cooled to 690°C, and pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, and 0.4% of the total weight of the melt is introduced as refining agent powder. The melt is aerated at 300r / min and a gas flow rate of 0.5sccm for 10min to remove slag and remove gas. It is then left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10La intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is designated A5.

[0023] Example 6 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 9.5 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.02 wt.%, Ce: 0.05 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0024] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10Ce intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 720°C to melt pure aluminum, then heated to 755°C to add Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, and pure Si alloys. After the intermediate alloy is melted, the furnace is cooled to 690°C, and pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, and 0.4% of the total weight of the melt is introduced as refining agent powder. The melt is aerated at 300r / min and a gas flow rate of 0.5sccm for 10min to remove slag and remove gas. It is then left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10Ce intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is designated A6.

[0025] Example 7 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 10 wt.%, Mg: 0.5 wt.%, Mn: 0.8 wt.%, Ti: 0.2 wt.%, Cu: 0.5 wt.%, V: 0.1 wt.%, La: 0.15 wt.%, Sr: 0.05 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0026] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10La intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloys are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10La intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is designated A7.

[0027] Example 8 This embodiment relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 8 wt.%, Mg: 0.1 wt.%, Mn: 0.5 wt.%, Ti: 0.05 wt.%, Cu: 0.05 wt.%, V: 0.01 wt.%, La: 0.01 wt.%, Sr: 0.01 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0028] The manufacture of the non-thermal treatment strengthened high strength die-casting aluminum silicon alloy of this embodiment and its die-casting process includes the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10La intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloys are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10La intermediate alloy is forced into the bottom area of ​​the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is approved, high pressure casting is performed at 690°C. The injection speed is 3m / s, the casting pressure is 80MPa, the release agent ratio is 1:100, and the mold temperature is 230°C. The mold used in the production process is a die-casting test bar mold, and the resulting casting is designated A8.

[0029] Comparative Example 1 This comparative example relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 8.0 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0030] The manufacture of the non-heat-treated reinforced high-strength die-casting aluminum silicon alloy of this comparative example and its die-casting process include the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, and Al-50Cu intermediate alloy, are preheated to 200°C and dried. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, and pure Si alloys are added. After the intermediate alloy is melted, the furnace is cooled to 690°C, and pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4 MPa is introduced into the melt, smelting agent powder of 0.4% of the total weight of the melt is introduced, and the melt is aerated for 10 minutes at 300 r / min and a gas flow rate of 0.5 sccm to remove slag and degas. The melt is then left to stand for 12 minutes, and the slag removal process is completed. And an on-site rapid composition analysis test is performed. After the composition passes, high pressure casting is performed at 690°C. The parameters of the die casting process and the die casting mold are the same as those in Example 1, and casting A9 is obtained.

[0031] Comparative Example 2 This comparative example relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 9.5 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0032] The manufacture of the non-heat-treated reinforced high-strength die-casting aluminum silicon alloy of this comparative example and its die-casting process include the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, and Al-50Cu intermediate alloy, are preheated to 200°C and dried. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, and pure Si alloys are added. After the intermediate alloy is melted, the furnace is cooled to 690°C, and pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4 MPa is introduced into the melt, smelting agent powder of 0.4% of the total weight of the melt is introduced, and the melt is aerated for 10 minutes at 300 r / min and a gas flow rate of 0.5 sccm to remove slag and degas. The melt is then left to stand for 12 minutes, and the slag removal process is completed. And an on-site rapid composition analysis test is performed. After the composition passes, high pressure casting is performed at 690°C. The parameters of the die casting process and the die casting mold are the same as those in Example 1, and casting A10 is obtained.

[0033] Comparative Example 3 This comparative example relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 9.5 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.05 wt.%, La: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0034] The manufacture of the non-heat-treated reinforced high-strength die-casting aluminum silicon alloy of this comparative example and its die-casting process include the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10La intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloys are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10La intermediate alloy is forced into the bottom region of the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is passed, high pressure casting is performed at 690°C. The parameters of the die casting process and the die casting mold are the same as those in Example 1, and casting A11 is obtained.

[0035] Comparative Example 4 This comparative example relates to a high-strength die-cast aluminum silicon alloy strengthened by non-heat treatment, with the weight percentages of each component being Si: 9.5 wt.%, Mg: 0.25 wt.%, Mn: 0.6 wt.%, Ti: 0.15 wt.%, Cu: 0.15 wt.%, V: 0.02 wt.%, La: 0.2 wt.%, Sr: 0.025 wt.%, Fe: 0.12 wt.%, the total amount of other impurities being 0.3 wt.%, and the remainder being Al.

[0036] The manufacture of the non-heat-treated reinforced high-strength die-casting aluminum silicon alloy of this comparative example and its die-casting process include the following steps: 1) Drying: The prepared raw materials, namely pure aluminum, pure Si, pure Mg, Al-10Mn intermediate alloy, Al-10Ti intermediate alloy, Al-50Cu intermediate alloy, Al-10La intermediate alloy, and Al-5V intermediate alloy, are preheated to 200°C and subjected to a drying treatment. 2) Smelting: The furnace is heated to 755°C to melt pure aluminum, then Al-10Ti, Al-50Cu, Al-10Mn, Al-5V, pure Si alloys are added, after the intermediate alloy is melted, the furnace is cooled to 690°C, pure Mg is pushed into the bottom area of ​​the crucible using a bell jar to melt, and then stirred for 5 minutes. The melt is then heated to 720°C, nitrogen gas with a pressure of 0.4MPa is introduced into the melt, 0.4% of the total weight of the melt is introduced as refining agent powder, and the melt is aerated at 300r / min and 0.5sccm gas flow rate for 10min to remove slag and remove gas. Then it is left to stand for 12 minutes, and the slag removal process is completed. After the refining is completed, the Al-10La intermediate alloy is forced into the bottom region of the crucible using a bell jar to melt, and stirred for 5 minutes until it is completely melted, then left to stand for 12 minutes, and an on-site rapid composition analysis test is performed. After the composition is passed, high pressure casting is performed at 690°C. The parameters of the die casting process and the die casting mold are the same as those in Example 1, and casting A12 is obtained.

[0037] The castings A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, and A12 manufactured in the above-mentioned Examples 1, 2, 3, 4, 5, 6, 7, and 8 and Comparative Examples 1, 2, 3, and 4, respectively, were subjected to mechanical performance tests, and the test results are shown in Table 1. Comparing the mechanical performance of the A1, A2, A3, and A9 castings, it can be seen that the strength and elongation of the alloys are obviously improved by adding V element or rare earth Er element alone, the tensile strength is improved by up to 27 MPa, and the improvement of the elongation reaches 24.1%. The improvement of the plasticity of the alloys by adding V and Er elements simultaneously is more significant, and the elongation of the castings is significantly improved from 8.7% (A9) to 14.9% (A3), with an amplification rate of 71.2%. Comparing the mechanical performance of the A4 and A10 castings, the above rule can be found as well. The combined addition of V and Er elements significantly improves the plasticity of die-cast aluminum alloys with high Si content (9.5wt.%), so that the elongation rate reaches 6.5% (A10 casting) to 12.9% (A4 casting), satisfying the high strength and high toughness properties of the alloy. Comparing the mechanical properties of A4, A5, A6 and A10 castings, the combined addition of V and Er, La and Ce rare earth elements can significantly improve the plasticity and tensile strength of die-cast aluminum alloys. Among them, the tensile strength of A4-A6 castings is ~281MPa (this symbol means about 281MPa), and the elongation rate is ~12.8%, which is 16.5% and 97% higher than the tensile strength and elongation rate of A10 casting, respectively. This explains why the three types of RE rare earths included in this patent all have a significant effect on the alloy. Comparing the mechanical properties of A5, A7, A8, A11 and A12 castings, the die-cast aluminum alloys with the combined addition of V and rare earth elements in the alloy composition range of this patent all have yield strengths greater than 120MPa, tensile strengths greater than 260MPa and elongations greater than 10% (A5, A7 and A8 castings), which demonstrate the excellent mechanical properties of the alloys in the composition range of this patent. After the V content of the alloy reaches 0.15 (casting A11) or the rare earth content of the alloy reaches 0.2 (casting A12), which is beyond the patent range, the elongation and tensile strength of the alloy decrease significantly, especially the elongation decreases to less than 8%, and a high-strength and high-toughness die-cast aluminum alloy material cannot be obtained.As described above, by adding V element and RE elements (La, Er, Ce) within the alloy composition range according to the present invention, the die-cast Al-Si alloy has the characteristics of high strength and high toughness in a non-heat-treated state. [Table 1]

[0038] Microstructure observation was performed on the castings A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, and A12 produced in the above Examples 1-8 and Comparative Examples 1-4, respectively. Comparing the microstructures of A1(a), A2(b), A3(c), and A9(i) as shown in FIG. 1, the eutectic Si structure is significantly refined with the introduction of V and rare earth element Er. When V and Er are not present in the alloy, the eutectic Si in the casting structure exhibits a layered structure as shown in FIG. 1(i), with a particle size of about 4 μm. With the introduction of V or Er element, the eutectic Si structure is transformed from layered to particle-like, and the particle size is significantly reduced to 1 μm, as shown in FIG. 1(a) and (b). With the combined addition of V and Er, the size of the eutectic Si in the structure is further reduced, and the eutectic Si exhibits a finer worm-like structure as shown in FIG. 1(c). The change in the microstructural features is closely related to the change in the mechanical properties. Obviously, the introduction of V and Er elements can significantly refine the eutectic Si structure and change its shape, which significantly changes the performance of the alloy. Comparison of the A4 and A10 microstructures shows that the combined action of V and Er elements is equally effective for alloys with high Si content. For an alloy with a Si content of 9.5 wt% and no V or Er elements added, the eutectic Si structure in the microstructure exhibits a coarse broken line shape, and the size of the broken line structure can reach up to 10 μm (Fig. 1(j)). Meanwhile, with the introduction of V and Er elements, the eutectic Si structure of the alloy is significantly refined into a worm-like shape (as shown in Fig. 1(d)), but the square block-shaped eutectic Si structure is localized, which has a certain effect on the plasticity of the alloy. Therefore, the plasticity of the A3 alloy is better than that of the A4 alloy. By comparing the A4, A5, A6, A7, A8 and A10 casting structures, it can be seen that in the alloy range of this patent, the combined addition of V and rare earth elements Er, La and Ce can eliminate the coarse broken line structure in the die-cast aluminum alloy, thereby ensuring the performance of the alloy. By comparing the A5, A11 and A12 casting structures, it can be seen that the addition of too much V element will cause the secondary phase of AlV in the alloy structure, and the addition of too much rare earth elements will cause the secondary phase of AlLa in the alloy, and these secondary phases will greatly reduce the plasticity of the alloy.In general, the combined action of V and RE elements introduced into the patented alloy further finely disperses the eutectic Si particles in the structure, and the morphology is also greatly improved, and this structural feature endows the alloy with excellent mechanical properties.

[0039] The above are merely examples of the present invention and do not limit the patent scope of the present invention. Conversion of an equivalent structure or equivalent flow made by using the specification of the present invention, or direct or indirect use in other related technical fields, is also included in the patent protection scope of the present invention.

Claims

1. A die-cast aluminum silicon alloy having high strength and high toughness and strengthened by non-thermal treatment, characterized in that the weight percentages of the respective components in said die-cast aluminum silicon alloy are Si 8.0-10.0 wt.%, Mg 0.1-0.5 wt.%, Mn 0.5-0.8 wt.%, Cu 0.05-0.5 wt.%, Ti 0.05-0.2 wt.%, Sr 0.01-0.05 wt.%, V 0.01-0.1 wt.%, RE 0.01-0.15 wt.%, Fe < 0.2 wt.%, the total amount of other impurities is ≦ 0.4 wt.%, and the balance is Al.

2. The high strength and high toughness die-casting aluminum silicon alloy strengthened by non-thermal treatment as claimed in claim 1, characterized in that the RE elements include one or more of La, Ce, and Er elements.

3. A method for producing the high strength and high toughness die-cast aluminum silicon alloy strengthened by non-thermal treatment according to claim 1, comprising the steps of: The manufacturing method includes: A drying step S1 in which the prepared raw materials of pure Al, pure Si, pure Mg, Al-Mn intermediate alloy, Al-Ti intermediate alloy, Al-Cu intermediate alloy, Al-RE intermediate alloy, and Al-V intermediate alloy are preheated and dried; S2 is a smelting step in which pure Al is melted by a first heating, and then an Al-Ti intermediate alloy, an Al-Cu intermediate alloy, an Al-Mn intermediate alloy, an Al-V intermediate alloy, and pure Si are added, and after the intermediate alloys have melted, the temperature is lowered, and pure Mg is injected into the bottom of the molten product and melted therein, and after the molten product is completely melted, the molten alloy is refined by a second heating, and further an Al-RE intermediate alloy is injected into the bottom of the molten product and melted therein, and after the molten product is completely melted, the molten alloy is allowed to stand, thereby obtaining a high-strength and high-toughness die-cast aluminum-silicon alloy that has been strengthened by no heat treatment; The method for producing the high strength and high toughness die-casting aluminum silicon alloy strengthened by non-thermal treatment according to claim 1, comprising:

4. 4. The method according to claim 3, wherein the preheating temperature in step S1 is 190 to 210° C.

5. 4. The method according to claim 3, wherein the temperature of the initial heating in step S2 is 750° C. to 760° C.

6. 4. The method according to claim 3, wherein the temperature in step S2 is lowered to a temperature of 680° C. to 700° C.

7. The method according to claim 3, wherein the temperature of the second heating in step S2 is 720 to 730° C.

8. The refining method according to claim 3, characterized in that in step S2, the refining agent powder is blown into the molten material by a rotary blowing device, and the refining agent powder is blown into the molten material to perform powder blowing refining, slag removal, and gas removal treatment, and then the molten material is left to stand for 10 to 15 minutes to complete the slag removal treatment, thereby obtaining the molten material after refining.

9. The manufacturing method according to claim 8, wherein the process parameters of the rotary spraying device are: rotation speed for gas removal 300-350 r / min, gas removal time 5-10 min, pressure of the gas source during gas removal 0.35±0.05 MPa, and gas flow rate 0.2-0.8 sccm.

10. The method according to claim 8, characterized in that the scouring agent used comprises one of magnesium chloride and calcium chloride.

Images