CN-116673491-B - Alloy multiscale strengthening phase in-situ precipitation regulation and control method and alloy casting

Abstract

The invention discloses an alloy multiscale strengthening phase in-situ precipitation regulation and control method and an alloy casting, and belongs to the technical field of metal preparation. The method comprises the steps of filling alloy melt in a crucible of casting equipment, filling liquid cooling medium around and below a substrate, spraying the alloy melt from an outlet of the crucible and impacting the alloy melt onto the substrate, realizing the regulation and control of a submicron precipitated phase and the formation of an alloy solidification layer under the action of melt spreading and flowing and the cooling actions of the substrate and the liquid cooling medium, moving the substrate downwards for a certain distance in the direction of the liquid cooling medium, repeating the processes, enabling the alloy melt to be continuously overlapped and formed on the alloy solidification layer, ensuring that the alloy solidification layer is subjected to the thermal circulation actions of a certain temperature and times before entering the liquid cooling medium, and realizing the regulation and the formation of a nanoscale strengthening phase and the formation of an alloy casting. The invention regulates and controls the solidification and solid phase change process of the alloy in a lamination mode, has short process flow and good regulation and control effect of the strengthening phase, and can obtain high-quality and high-performance alloy castings.

Inventors

• LIU XUEFENG
• LI ANG
• WANG XIN
• CHEN JUNZHEN
• JIANG ZIWEI

Assignees

• 北京科技大学

Dates

Publication Date

20260505

Application Date

20230602

Claims (4)

1. 1. The method for regulating and controlling the in-situ precipitation of the alloy multiscale strengthening phase is characterized by comprising the following steps of: firstly, accommodating 7075 aluminum alloy melt in a crucible of casting equipment, and filling liquid cooling medium around and below a base plate of the casting equipment; Spraying 7075 aluminum alloy melt from an outlet of a crucible at a speed of 6000 mm/s and impacting the 7075 aluminum alloy melt onto a substrate, forming a 7075 aluminum alloy solidification layer with a thickness of 1 mm by adopting an additive manufacturing mode, rapidly spreading the 7075 aluminum alloy melt after impacting the surface of the substrate, forming a high-speed annular flow field formed by impacting the 7075 aluminum alloy melt on the substrate at the front edge of a solid-liquid interface of the spread 7075 aluminum alloy melt, enabling a AlZnMgCu submicron precipitated phase to be sufficiently and largely nucleated, enabling the 7075 aluminum alloy melt to be always cooled at a speed of 5000 ℃/s under the cooling action of the substrate and a liquid cooling medium, reducing the growth speed of the AlZnMgCu submicron precipitated phase, and finally refining and enabling the AlZnMgCu submicron precipitated phase with an average size of 0.5 μm to be intermittently distributed; Thirdly, downwards moving the substrate to a distance of 1 mm to the liquid cooling medium, and performing online accurate displacement control to ensure that the distance between the liquid level of the liquid cooling medium and the upper surface of the formed 7075 aluminum alloy solidification layer is always maintained at 40 mm; Fourth, repeating the forming process of the 7075 aluminum alloy melt in the second step and the third step, so that the 7075 aluminum alloy melt is continuously solidified and overlapped on the 7075 aluminum alloy solidification layer for forming; by precisely controlling the downward moving distance of the substrate, the formed 7075 aluminum alloy solidification layer is ensured to be subjected to 40 times of thermal circulation before entering a liquid cooling medium, the highest temperature of the thermal circulation is maintained at 270 ℃ and the lowest temperature is maintained at 80 ℃, so that MgZn nanoscale strengthening phases with average particle size of 9 nm and which are in common with a matrix are controllably dispersed and separated out from the matrix of the solidified alloy until 7075 aluminum alloy billets with required thickness are obtained.
2. 2. The method for in-situ precipitation control of an alloy multiscale strengthening phase according to claim 1, wherein the substrate is a mold having a complex shape.
3. 3. The method for regulating and controlling in-situ precipitation of an alloy multi-scale strengthening phase according to claim 1, wherein the liquid cooling medium comprises water or a low-melting-point alloy, the melting point of the low-melting-point alloy is 10-100 ℃, and the low-melting-point alloy is at least one of gallium-indium alloy, gallium-indium-tin alloy and indium-tin-bismuth-lead alloy.
4. 4. An alloy casting, characterized in that the alloy casting is prepared by adopting the alloy multiscale strengthening phase in-situ precipitation regulation method according to any one of claims 1 to 3.

Description

Alloy multiscale strengthening phase in-situ precipitation regulation and control method and alloy casting Technical Field The invention belongs to the technical field of metal preparation, and particularly relates to an alloy multiscale strengthening phase in-situ precipitation regulation and control method and an alloy casting. Background Second phase strengthening is an important strengthening mode of alloys. The strengthening phase of the alloy generally comprises a small submicron precipitated phase which is discontinuously distributed and a nanometer strengthening phase which is dispersed. The fine submicron grade precipitation phase is usually formed under the action of solute redistribution in the alloy solidification process, is positioned at a grain boundary, can increase the stability of the grain boundary, is favorable for improving the room temperature and high temperature strength of the alloy, and the nanometer grade strengthening phase in the grain boundary is usually precipitated from a supersaturated matrix in the alloy solid-state phase transformation, can prevent dislocation movement in the deformation process, and improves the comprehensive mechanical property of the alloy. The problems of slow solidification speed, uneven heating and cooling speeds and the like of the traditional solidification process and solid phase change process of the alloy are limited, submicron precipitated phases of the alloy are easy to grow excessively and are distributed in a continuous net shape, and nanoscale reinforced phases are large in size, small in number and uneven in distribution, so that adverse effects are generated on the strength and plasticity of the alloy. At present, the regulation and control of the alloy strengthening phase are mainly to regulate and control the submicron precipitated phase and the nanometer strengthening phase of the alloy respectively. The method comprises refining, reducing or crushing coarse continuous submicron precipitated phases of alloy by improving solidification process or adding solution treatment and plastic deformation process, uniformly precipitating nanoscale strengthening phases of alloy from matrix by improving aging treatment process, reducing the size of nanoscale strengthening phases and increasing the number thereof by controlling aging temperature and time. The regulation and control method of the alloy strengthening phase can respectively realize the regulation and control of the alloy submicron precipitated phase and the nanometer strengthening phase, but simultaneously has the following problems: (1) The regulation and control of the existing alloy strengthening phase, in particular to the regulation and control of the nanoscale strengthening phase, is realized by heat treatment after the alloy is solidified and formed, and the method for in-situ regulation and control of the strengthening phase in the alloy solidification and forming process is lacked, so that the process flow is longer; (2) The existing regulation and control methods of alloy strengthening phases are mainly used for regulating and controlling submicron precipitated phases and nanoscale strengthening phases respectively, and the regulation and control effects of the strengthening phases are poor due to the lack of an integrated regulation and control method of the multiscale strengthening phases. Therefore, the alloy multiscale strengthening phase in-situ precipitation regulation and control method with short process flow and good strengthening phase regulation and control effect is developed, and the alloy casting with high quality and high performance is obtained, so that the method has important significance. Disclosure of Invention Aiming at the problems of lack of an in-situ integrated regulation and control method of a multi-scale strengthening phase in the alloy solidification forming process, long process flow, poor regulation and control effect of the strengthening phase and the like in the traditional alloy strengthening phase regulation and control, the invention provides an in-situ precipitation regulation and control method of the alloy multi-scale strengthening phase and an alloy casting, and realizes in-situ precipitation regulation and control of the alloy multi-scale strengthening phase. According to a first aspect of the technical scheme of the invention, an alloy multi-scale strengthening phase in-situ precipitation regulation and control method is provided, which comprises the following steps: the method comprises the steps of firstly, filling alloy melt in a crucible of casting equipment, and filling liquid cooling medium around and below a base plate of the casting equipment; the second step is that the alloy melt is sprayed out from the outlet of the crucible and impacted onto the substrate to finish the formation of a layer of alloy solidification layer, the alloy melt spreads rapidly after impacting onto the surface of the substrate, and the alloy melt is