High-speed rail heat-treatment-free high-strength die-casting aluminum alloy and

Abstract

The invention provides a high-speed rail heat-treatment-free high-strength die-casting aluminum alloy and a design method thereof.The design method comprises the steps that original data of the heat-treatment-free die-casting aluminum alloy are collected, and each set of original data comprises component, mechanical property and structure property data of the heat-treatment-free die-casting aluminum alloy; element features contained in the components serve as calculation input, thermodynamic feature calculation of the multiple components is conducted, and thermodynamic feature data are output; establishing a mapping relation between thermodynamic characteristic data and mechanical properties, and realizing multi-objective optimization through two-step screening of coarse screening and optimal screening; preparing an alloy sample according to components of the die-casting aluminum alloy designed in a high-throughput manner; and if the performance of the alloy sample does not meet the target performance requirement, the screening method of the alloy components is optimized according to the test result of the alloy sample, and alloy screening is conducted again till the die-casting aluminum alloy components meeting the target performance requirement are obtained. According to the method, the alloy with a specific demand target can be designed, and the alloy design efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy materials, and in particular to a high-strength die-cast aluminum alloy free of heat treatment and a design method thereof. Background Art

[0002] Aluminum alloys are widely used in aerospace, automobile manufacturing and other fields due to their light weight, high strength and excellent processing performance. With the implementation of lightweight development and the rapid development of die-casting equipment and process technology, the use of high-pressure integrated forming to prepare automotive load-bearing structural parts has become an important way to achieve lightweighting for new energy vehicles. Integrated die-casting aluminum alloys have the advantages of high product quality and high production efficiency. The castings have high dimensional accuracy, good surface finish, high strength and hardness. They can realize the integrated manufacturing of multiple parts, reduce the welding of parts, greatly improve the overall performance of the product, achieve lightweighting of the whole vehicle, and reduce manufacturing costs. Heat treatment is one of the important means to improve the strength and plasticity of aluminum alloys, but die-cast thin-walled parts are prone to deformation or bubbles during the heat treatment process, which seriously affects the yield of parts and increases the processing steps and energy consumption. Therefore, the development of integrated die-casting of aluminum alloys with high strength and high toughness that do not require heat treatment is a hot topic in current research.

[0003] At present, die-cast aluminum alloys are mainly Al-Si and Al-Mg aluminum alloys. Among them, Al-Si aluminum alloys have good casting properties, but poor alloy strength and plasticity; while Al-Mg aluminum alloys have good strength and plasticity and good corrosion resistance, but their casting properties are poor. In addition, Fe, as one of the most important harmful elements in aluminum alloys, has a significant deteriorating effect on the performance of the alloy, greatly reducing the strength and plasticity of the alloy; therefore, in traditional die-cast aluminum alloys, in order to eliminate the adverse effects of the Fe element, the Fe content is controlled in an extremely low range.

[0004] As far as metal materials are concerned, microalloying has a crucial influence on the organization, structure and performance of the materials. Therefore, clarifying the influence of alloying elements on the performance of die-cast aluminum alloys is of great significance for the research and development of high-performance heat-treatment-free die-cast aluminum alloys. The traditional alloy design method is mainly the "trial and error method", which designs different aluminum alloy compositions by adding different alloying elements such as Mg, Cu and Si; although some alloy compositions that meet the performance requirements can be designed, there are problems such as long process flow, time-consuming and labor-intensive, and low efficiency, which makes it difficult to meet the needs of today's rapidly developing society. Therefore, finding an efficient alloy design method is crucial to the development of high-performance aluminum alloys. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a high-strength die-cast aluminum alloy that does not require heat treatment and a design method thereof.

[0006] According to one aspect of the present invention, a design method for a high-strength die-cast aluminum alloy without heat treatment is provided, comprising:

[0007] Collect the original data of heat-treatment-free die-casting aluminum alloy, each set of original data includes the composition, mechanical properties and microstructure performance data of heat-treatment-free die-casting aluminum alloy;

[0008] Taking the element characteristics contained in the composition of the heat treatment-free die-casting aluminum alloy as calculation input, performing multi-component thermodynamic characteristic calculation, and outputting thermodynamic characteristic data;

[0009] A mapping relationship between the thermodynamic characteristic data and the mechanical properties is established, and multi-objective optimization is achieved through two steps of coarse screening and optimal screening to obtain a high-throughput designed die-casting aluminum alloy composition;

[0010] preparing an alloy sample according to the high-throughput designed die-casting aluminum alloy composition, and verifying whether the performance of the alloy sample meets the target performance requirements;

[0011] If the target performance requirements are not met, the alloy composition screening method is optimized according to the test results of the alloy sample, and the alloy is screened again until a die-casting aluminum alloy composition that meets the target performance requirements is obtained.

[0012] Furthermore, each set of original data includes composition, mechanical properties and microstructure performance data of the heat-treatment-free die-casting aluminum alloy; wherein:

[0013] The composition is the elements constituting the die-casting aluminum alloy and their corresponding mass percentages, and the elements include at least Al, Si, Mn, Fe, Ni, Ti, Mg, Cu and Zn;

[0014] The mechanical properties include tensile strength and yield strength;

[0015] The organizational properties include phase composition and structural morphology.

[0016] Furthermore, the multi-objective optimization is achieved through two steps of screening, namely, rough screening and optimal screening, wherein: in the rough screening stage, the alloy components are qualitatively screened through a decision tree and preset screening conditions.

[0017] Furthermore, the preset screening conditions include: alloy solidification temperature range, content of Fe-containing second phase, content of other strengthening phases and content of solid solution elements in the alloy matrix.

[0018] Furthermore, the multi-objective optimization is achieved through two steps of screening, namely, coarse screening and optimization screening, wherein: in the optimization screening stage, the optimal alloy composition is determined by the contribution of each relative mechanical property in the alloy.

[0019] Furthermore, the contribution of each relative mechanical property in the alloy includes a linear term σ1 and a cross term σ2; wherein:

[0020] The linear term σ1 is determined on the basis of assuming that the strength difference of materials with different alloy components is derived from the difference in solid solubility of each element in the alloy system and the different contributions of different strengthening phases;

[0021] The cross term σ2 is determined by taking into account the co-precipitation effect caused by the simultaneous generation of multiple second phases.

[0022] Furthermore, the linear term σ1 is represented by the linear superposition of the solid solubility of each element and the strength contribution of different strengthening phases to the alloy component material. The expression of the linear term σ1 is:

[0023] σ1=Σσ i w i +Σk i c i

[0024] In the formula, σ i represents the strength of the strengthening phase, w i Indicates the content of strengthening phase, k i represents the strengthening coefficient of the solid solution element, c i Indicates the concentration of dissolved elements.

[0025] Furthermore, the expression of the cross term σ2 is:

[0026] σ2=ΣΔσ i-j w i w j

[0027] In the formula, σ i-j represents the strengthening amount of the interaction between the two phases, w i 、w j Represent the contents of the two phases respectively.

[0028] According to another aspect of the present invention, a high-strength die-cast aluminum alloy that does not require heat treatment is provided. The alloy is designed using the above-mentioned design method for the high-strength die-cast aluminum alloy that does not require heat treatment. In terms of mass percentage, the alloy includes: Si6-12%, Cu 1-3%, Fe 0.1-0.6%, Mg 0.1-1%, Mn 0-0.6%, Ni 0-0.3%, Zn 0.05-3%, Ti 0-1%, V 0-0.2%, and the rest is Al.

[0029] Preferably, the alloy comprises, by mass percentage, 9.2% Si, 2.1% Cu, 0.4% Fe, 0.2% Mg, 0.5% Mn, 0.1% Ni, 0.1% Zn, 0.1% Ti, and the remainder is Al.

[0030] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0031] 1. The present invention utilizes thermodynamic integrated calculations to perform thousands of calculations in the user-defined alloy composition space, realizes large amounts of data screening, accelerates the alloy design process, avoids the time-consuming and labor-intensive drawbacks of traditional methods, and improves alloy design efficiency.

[0032] 2. The present invention can design alloys for specific target needs, thus avoiding the blindness of the traditional trial-and-error method in developing new alloys.

[0033] 3. The alloy designed by the present invention has good mechanical properties; in addition, the Fe content in the alloy composition is relatively high, and the alloy preparation can use recycled aluminum as a raw material, thereby realizing the recycling of aluminum and reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0035] Figure 1 It is a schematic flow chart of a design method of a high-strength die-cast aluminum alloy for high-speed iron without heat treatment in one embodiment of the present invention;

[0036] Figure 2 It is the process and parameter setting of high-throughput calculation of high-strength die-cast aluminum alloy without heat treatment for high-speed iron in one embodiment of the present invention;

[0037] Figure 3 is a schematic diagram of a process for performing feature screening on calculation results in one embodiment of the present invention;

[0038] Figure 4 is a projection diagram of the alloy composition screening result in one embodiment of the present invention;

[0039] Figure 5 1 is a stress-strain curve diagram of an aluminum alloy prepared according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0041] The embodiment of the present invention provides a design method for high-strength die-cast aluminum alloy without heat treatment for high iron, which performs thousands of calculations in the alloy composition space defined by the user through high throughput calculation (HTC) and integrated calculation methods, and then screens the calculation results through the established screening criteria to obtain the optimal alloy composition. The design method includes:

[0042] S1. Determine alloy elements and calculation range: clarify alloy performance requirements, collect a large amount of original data of heat-treatment-free die-casting aluminum alloys, each set of original data includes composition, mechanical properties and microstructure performance data of heat-treatment-free die-casting aluminum alloys;

[0043] S2. Thermodynamic integrated calculation: taking the element characteristics contained in the composition of the heat treatment-free die-casting aluminum alloy as calculation input, performing thermodynamic characteristic calculation of multiple components, and outputting thermodynamic characteristic data;

[0044] S3. Construct screening criteria: Establish the mapping relationship between thermodynamic characteristic data and mechanical properties, and achieve accurate matching between the selected alloy composition and the expected performance indicators through two-step screening of coarse screening and optimal screening (fine screening), realize multi-objective optimization of strength, plasticity and thermal conductivity, and obtain the die-casting aluminum alloy composition for high-throughput design;

[0045] S4. Experimental verification: Prepare alloy samples according to the high-throughput designed die-casting aluminum alloy composition to verify whether the performance of the alloy samples meets the target performance requirements;

[0046] If the target performance requirements are not met, the alloy composition screening method is optimized according to the test results of the alloy sample, and the alloy is screened again until a die-casting aluminum alloy composition that meets the target performance requirements is obtained.

[0047] The embodiment of the present invention utilizes a high-throughput computing method to design the composition of high-performance die-cast aluminum alloys, clarifies the correspondence between material composition, organizational structure and performance through data mining, and can realize the calculation of thousands of alloy compositions in a user-defined space. It can quickly design material compositions that meet the requirements according to target needs, avoiding the blindness and time-consuming and labor-intensive shortcomings of the traditional trial-and-error method for developing new alloys, speeding up the process of material development, and reducing the cost of trial-and-error.

[0048] The embodiment of the present invention is mainly aimed at the composition design of high-performance heat-treatment-free die-cast aluminum alloy, and the main indicator is alloy strength. The design alloy element composition and its calculation range are mainly determined through the collected data information. Each set of original data includes the composition, mechanical properties and microstructure performance data of the heat-treatment-free die-cast aluminum alloy; wherein: the composition is the elements constituting the die-cast aluminum alloy and their corresponding mass percentages, and the elements include at least Al, Si, Mn, Fe, Ni, Ti, Mg, Cu and Zn; the mechanical properties include tensile strength and yield strength; the microstructure properties include phase composition and structural morphology, based on which the composition and content range of the aluminum alloy can be determined.

[0049] In some embodiments, in step S2, thermodynamic software such as Pandat software can be used to perform high-throughput calculations on the determined alloying elements (selected alloying elements and composition ranges); by calling the aluminum alloy database in the software, the element characteristics are used as input, and the corresponding thermodynamic variables are used as output to complete the calculation of different alloy components. The key to this step is to select which variables to calculate. Specifically including: selecting a determined element component, calculating the input of the element, setting the range of high-throughput calculations of each element of the alloy and the calculation step size, wherein the main elements in the alloy are usually set with a larger step size, and the trace elements are set with a smaller step size; the temperature calculation interval and step size of each component are set, and the solidification mode of the alloy during the solidification process (equilibrium and non-equilibrium solidification), selecting the thermodynamic property variables that need to be calculated and output, and starting high-throughput simulation calculations.

[0050] In step S3, reasonable screening criteria are established to screen the calculation results. Specifically, the output thermodynamic data are sorted, and the calculated alloy components are classified and screened according to the set screening criteria to obtain the die-casting aluminum alloy components that meet the performance target. The key to this step is how to construct the mapping relationship between the output variables and the alloy properties. Not all variables obtained by calculation can be quantitatively constructed to have a relationship with properties such as alloy strength. Therefore, establishing appropriate screening criteria is crucial to obtaining high-performance target alloy components. In order to accurately match the relationship between the calculated variables and alloy properties, the screening process is divided into two steps, including: coarse screening and optimal screening (fine screening). In the coarse screening stage, the alloy components are qualitatively screened together by the decision tree and the proposed screening conditions; and in the fine screening stage, the optimal alloy component is selected by considering the contribution of each relative mechanical property in the alloy.

[0051] In the coarse screening stage, the output variables that can only be qualitatively analyzed are used as the main screening variables. At the same time, considering the complexity of the mechanism of mechanical properties of materials, in order not to miss any local optimal point, the decision tree framework and the preset screening conditions are combined to screen the alloy components step by step to achieve qualitative screening of alloy components. In some embodiments, the preset screening conditions include: alloy solidification temperature range, content of Fe-containing second phase (β-AlFeSi and α-AlFeSi, etc.), content of other strengthening phases and content of solid solution elements in the alloy matrix, wherein other strengthening phases refer to other second phases other than Fe-containing second phases.

[0052] In some embodiments, during the optimization screening stage, a mapping relationship between quantitatively analyzable variables and alloy properties is constructed, and the optimal alloy composition is determined by the contribution of each relative mechanical property in the alloy.

[0053] The microstructure and performance data include the phase composition and content and morphological characteristics in the alloy, and the content of the second phase is controlled according to the microstructure and performance data during the screening process. In some embodiments, the contribution of each phase in the alloy to the mechanical properties includes a linear term σ1 and a cross term σ2; wherein: the linear term σ1 is determined on the basis of assuming that the strength difference of materials with different alloy components comes from the difference in the solid solubility of each element in the alloy system and the different contributions of different strengthening phases; the cross term σ2 is determined by considering the co-precipitation effect caused by the simultaneous generation of multiple second phases.

[0054] Specifically, the linear term σ1 is represented by the linear superposition of the solid solubility of each element and the strength contribution of different strengthening phases to the alloy component materials. The expression of the linear term σ1 is: σ1 = Σσ i w i +Σk i c i ; In the formula, σ i represents the strength of the strengthening phase, w i Indicates the content of strengthening phase, k i represents the strengthening coefficient of the solid solution element, c i Indicates the concentration of dissolved elements.

[0055] The expression of the cross term σ2 is: σ2=ΣΔσ i-j w i w j ; In the formula, σ i-j represents the strengthening amount of the interaction between the two phases, w i 、w j Represent the contents of the two phases respectively.

[0056] The corresponding values ​​can be estimated by using the software Jmatpro and its related database, and then put into the above formula for calculation. According to the calculation results, the larger the sum of the linear term and the cross term, the higher the alloy strength, and the alloy composition corresponding to the maximum value is the optimal alloy composition.

[0057] In step S4, an alloy sample is prepared according to the aluminum alloy composition obtained by screening, and it is verified whether the performance of the sample meets the target performance requirements; specifically, recycled aluminum can be used as a raw material, and an aluminum alloy composition sample obtained by high-throughput calculation can be prepared by high-pressure die casting, and its chemical composition and mechanical properties are tested. If it does not meet the target performance requirements, the screening criteria of the alloy composition are optimized according to the test results, and the alloy composition screening process is repeated. Specifically, the microstructure, phase composition and content of the alloy are tested and analyzed to determine whether it meets the preset screening conditions, and the difference from the set conditions is analyzed, and the screening condition setting is guided accordingly, through multiple cycles of iteration, until a die-cast aluminum alloy sample that meets the target performance requirements is finally obtained.

[0058] The alloy design method in the above embodiment of the present invention includes: collecting common alloy components of heat-free die-cast aluminum alloys, determining the composition and element range of the alloy; taking the alloy components as input, and taking the calculated thermodynamic data and characteristics as output; taking the thermodynamic criterion as the intermediate medium, establishing the mapping relationship between the alloy components and the performance, setting the appropriate screening conditions, and obtaining the die-cast aluminum alloy components that meet the performance requirements. Prepare alloy samples according to the screened alloy components, test the performance of the alloy, and judge whether the performance of the alloy meets the screening requirements; if it does not meet the target performance requirements, analyze the alloy samples, optimize the alloy screening conditions, and screen the calculated alloy again until a die-cast aluminum alloy sample that meets the target performance requirements is obtained, thereby realizing the design of aluminum alloy components with high Fe content. The aluminum alloy designed in the embodiment of the present invention has high strength, and is expected to realize integrated die-casting in structural parts such as the body of new energy vehicles, and has broad application prospects; in addition, the design method in the above embodiment of the present invention can improve the efficiency of aluminum alloy component design, avoid the blindness of the traditional trial and error method to develop high iron content die-cast aluminum alloys, and use recycled aluminum as raw material to prepare alloy samples, which is helpful to promote the reuse of recycled aluminum alloys and greatly reduce the use cost of aluminum alloys.

[0059] Another embodiment of the present invention provides a high-strength die-cast aluminum alloy that does not require heat treatment for high iron, which is designed using the above-mentioned design method for the high-strength die-cast aluminum alloy that does not require heat treatment for high iron. According to mass percentage, the alloy includes: Si 6-12%, Cu 1-3%, Fe 0.1-0.6%, Mg 0.1-1%, Mn 0-0.6%, Ni 0-0.3%, Zn 0.05-3%, Ti 0-1%, V0-0.2%, and the rest is Al.

[0060] Preferably, the alloy comprises, by mass percentage, 9.2% Si, 2.1% Cu, 0.4% Fe, 0.2% Mg, 0.5% Mn, 0.1% Ni, 0.1% Zn, 0.1% Ti, and the remainder Al.

[0061] The die-cast aluminum alloys used in existing load-bearing structural parts have strict control standards for the Fe content, most of which are less than 0.1%. The above-mentioned die-cast aluminum alloy has a higher Fe content. The alloy with the above formula has high strength and high thermal conductivity, and can be used in automobile manufacturing to meet the performance requirements of automobile structural parts.

[0062] In a specific embodiment, continue to refer to Figure 1 , a design method based on high-throughput calculation for high-speed rail high-strength heat-treatment-free die-casting aluminum alloy, the main steps are as follows:

[0063] Step 1: Determine alloy elements and calculation range

[0064] The composition, mechanical properties and corresponding microstructure and performance data of multiple groups of heat-treatment-free die-cast aluminum alloys were collected; the composition refers to the elements constituting the die-cast aluminum alloy and their corresponding mass percentages, including various elements such as Al, Si, Mn, Fe, Ni, Ti, Mg, V, Cu, RE and Zn; the mechanical properties include the tensile strength and yield strength σ of the alloy; the alloy microstructure mainly includes the phase composition and structural morphology corresponding to the corresponding components.

[0065] Step 2: Thermodynamic software calculation

[0066] The thermodynamic software Pandat is mainly used to perform high-throughput calculations on the determined alloy elements; by calling the aluminum alloy database, the characteristics of more than 10 elements contained in the collected components are used as calculation inputs, and the thermodynamic characteristic data are used as outputs to perform multi-component thermodynamic calculations on the input multiple element characteristics; Figure 2 As shown, it specifically includes: input of calculation elements, setting the range of high-throughput calculation of each element and the calculation step, among which the main elements in the alloy are usually set with a larger step, while the trace elements are set with a smaller step; the temperature calculation range and step of each component, as well as the solidification mode of the alloy during the solidification process (equilibrium and non-equilibrium solidification), and selecting the thermodynamic variables that need to be calculated and output.

[0067] Step 3: Construct screening criteria

[0068] Establishing the mapping relationship between the calculated output variables and the alloy properties, in order to accurately match the relationship between the calculated variables and the alloy properties, we divide the screening process into two steps, including: coarse screening and optimization. In the coarse screening stage, the output variables that can only be analyzed qualitatively are used as the main screening variables. At the same time, considering the complexity of the mechanism of the mechanical properties of the material, in order not to miss any local optimal point, the embodiment of the present invention constructs a set of Figure 3 The screening conditions shown are combined with the decision tree framework to perform a step-by-step screening method for alloy composition screening. Figure 3 Conditions 1 to 4 in the formula correspond to the four conditions of the coarse screening, including: (1) alloy solidification temperature range; (2) content of Fe-containing second phase (β-AlFeSi and α-AlFeSi, etc.); (3) content of other strengthening phases; (4) content of solid solution elements in the alloy matrix. "Top A%" means sorting the elements mentioned in the conditions and then selecting the top A%. First, the alloy solidification temperature range in the component set obtained from the set component space is sorted in ascending order, and the alloy components of the last A% are eliminated. Then, the second phase content of the remaining components is calculated, the results are sorted, and the next step of screening is started, and so on. The elimination set represents the components that are screened out and do not meet the requirements.

[0069] The projection diagram of the rough screening result is as follows: Figure 4 As shown in the figure, different colors represent the component space that meets the requirements during the screening process. For example, after condition 1 is screened, it is the area corresponding to the four colors, and after condition 2, it is blue + red + yellow, and so on. The area that meets all conditions is the yellow area.

[0070] In the fine screening stage, the embodiment of the present invention constructs a mapping relationship between quantitatively analyzable variables and alloy properties, and selects the optimal alloy composition mainly by considering the contribution of each relative mechanical property in the alloy, including: linear term σ1 and cross term σ2; it is assumed that the strength difference of materials with different alloy compositions mainly comes from the difference in solid solubility of each element in the alloy system and the different contributions of different strengthening phases, and the result can be represented by the linear superposition of each term, which can be expressed as:

[0071] σ1=Σσ i w i +Σk i c i

[0072] The cross term mainly considers the co-precipitation effect caused by the simultaneous generation of multiple second phases, etc., which can be expressed as:

[0073] σ2=ΣΔσ i-j w i w j

[0074] Among them, σ i and wi represent the strength and content of the strengthening phase, respectively, and k i and c i They respectively represent the strengthening coefficient and concentration of the solid solution elements. The corresponding values ​​can be estimated using the software Jmatpro and its related database and then brought into the above formula for calculation.

[0075] According to the above calculation results, the larger the calculated value is, the higher the alloy strength is, and the alloy composition corresponding to the maximum value is the optimal alloy composition.

[0076] Step 4: Experimental verification

[0077] The aluminum alloy composition samples obtained by high-throughput calculation are prepared by high-pressure die casting, and their chemical composition and mechanical properties are tested to verify whether the designed alloy composition meets the target performance requirements. If it does not meet the target performance requirements, the screening criteria of the alloy composition are optimized according to the test results, and the alloy composition screening process is repeated. After multiple cycles of iteration, the alloy composition that meets the target performance requirements is finally obtained. Among them, in terms of mass percentage, the components that meet the target requirements include: Si: 6-12%, Cu: 1-3%, Fe: 0.1-0.6%; Mg: 0.1-1%, Mn: 0-0.6%, Ni: 0-0.3%, Zn: 0.05-3%, Ti: 0-1%, V: 0-0.2%, and the rest is Al.

[0078] Based on the above steps, a heat-treatment-free die-casting aluminum alloy is obtained, which includes Si9.2%, Cu 2.1%, Fe 0.4%, Mg 0.2%, Mn 0.5%, Ni 0.1%, Zn 0.1%, Ti 0.1%, and the rest is Al. The mechanical properties of the alloy sample are obtained by preparing the alloy sample and conducting mechanical property tests. Figure 5 As shown, the tensile strength of the alloy sample reaches 281MPa and the elongation is 3.6%, which shows good mechanical properties.

[0079] The above-mentioned embodiments of the present invention can quickly and efficiently develop high-speed iron heat-treatment-free die-casting aluminum alloy compositions that meet the target performance requirements through a high-throughput calculation method, avoid the blindness of developing new die-casting aluminum alloys using the traditional trial-and-error method, and improve the efficiency of die-casting aluminum alloy composition design.

[0080] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims, which does not affect the essence of the present invention. The above preferred features can be used in any combination without conflicting with each other.

Claims

1. A design method for high-strength die-cast aluminum alloy without heat treatment for high-speed rail, characterized in that: include: Collect the original data of heat-treatment-free die-casting aluminum alloy, each set of original data includes the composition, mechanical properties and microstructure performance data of heat-treatment-free die-casting aluminum alloy; Taking the element characteristics contained in the composition of the heat treatment-free die-casting aluminum alloy as calculation input, performing multi-component thermodynamic characteristic calculation, and outputting thermodynamic characteristic data; A mapping relationship between the thermodynamic characteristic data and the mechanical properties is established, and multi-objective optimization is achieved through two steps of coarse screening and optimal screening to obtain a high-throughput designed die-casting aluminum alloy composition; preparing an alloy sample according to the high-throughput designed die-casting aluminum alloy composition, and verifying whether the performance of the alloy sample meets the target performance requirements; If the target performance requirements are not met, the alloy composition screening method is optimized according to the test results of the alloy sample, and the alloy is screened again until a die-casting aluminum alloy composition that meets the target performance requirements is obtained.

2. The design method of high-strength die-cast aluminum alloy without heat treatment for high-speed iron according to claim 1 is characterized in that: Each set of original data includes composition, mechanical properties and microstructure performance data of heat-treatment-free die-casting aluminum alloy; wherein: The composition is the elements constituting the die-casting aluminum alloy and their corresponding mass percentages, and the elements include at least Al, Si, Mn, Fe, Ni, Ti, Mg, Cu and Zn; The mechanical properties include tensile strength and yield strength; The organizational properties include phase composition and structural morphology.

3. The design method of high-strength die-cast aluminum alloy for high-speed iron without heat treatment according to claim 1 is characterized in that: The multi-objective optimization is achieved through two steps of screening, namely, rough screening and optimal screening, wherein: in the rough screening stage, the alloy components are qualitatively screened through a decision tree and preset screening conditions.

4. The design method of high-strength die-cast aluminum alloy without heat treatment for high-speed iron according to claim 3 is characterized in that: The preset screening conditions include: alloy solidification temperature range, content of Fe-containing second phase, content of other strengthening phases and content of solid solution elements in the alloy matrix.

5. The design method of high-strength die-cast aluminum alloy for high-speed iron without heat treatment according to claim 1, characterized in that: The multi-objective optimization is achieved through two steps of screening, namely, coarse screening and optimization screening, wherein: in the optimization screening stage, the optimal alloy composition is determined by the contribution of each relative mechanical property in the alloy.

6. The design method of high-strength die-cast aluminum alloy for high-speed iron without heat treatment according to claim 5, characterized in that: The contribution of each relative mechanical property in the alloy includes a linear term σ1 and a cross term σ2; wherein: The linear term σ1 is determined on the basis of assuming that the strength difference of materials with different alloy components is derived from the difference in solid solubility of each element in the alloy system and the different contributions of different strengthening phases; The cross term σ2 is determined by taking into account the co-precipitation effect caused by the simultaneous generation of multiple second phases.

7. The design method of high-strength die-cast aluminum alloy for high-speed iron without heat treatment according to claim 6, characterized in that: The linear term σ1 is represented by the linear superposition of the solid solubility of each element and the strength contribution of different strengthening phases to the alloy component material. The expression of the linear term σ1 is: σ1=Σσ i w i +Sk i c i In the formula, σ i represents the strength of the strengthening phase, w i Indicates the content of strengthening phase, k i represents the strengthening coefficient of the solid solution element, c i Indicates the concentration of dissolved elements.

8. The design method of high-strength die-cast aluminum alloy without heat treatment for high-speed iron according to claim 6, characterized in that: The expression of the cross term σ2 is: σ2=SDS i-j w i w j In the formula, σ i-j represents the strengthening amount of the interaction between the two phases, w i 、w j Represent the contents of the two phases respectively.

9. A high-strength die-cast aluminum alloy without heat treatment for high-speed iron, characterized in that: The high-strength die-cast aluminum alloy without heat treatment for high iron is designed by the design method according to any one of claims 1 to 8. The alloy comprises, by mass percentage, Si 6-12%, Cu 1-3%, Fe 0.1-0.6%, Mg 0.1-1%, Mn 0-0.6%, Ni 0-0.3%, Zn 0.05-3%, Ti 0-1%, V 0-0.2%, and the rest is Al.

10. The high-strength die-cast aluminum alloy without heat treatment according to claim 9, characterized in that: Calculated by mass percentage, the alloy includes: Si 9.2%, Cu 2.1%, Fe 0.4%, Mg 0.2%, Mn 0.5%, Ni 0.1%, Zn 0.1%, Ti 0.1%, and the rest is Al.

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