Method for preparing alloy semi-solid thixotropic blank by continuously extruding elementary substance mixed powder

Abstract

The invention discloses a method for preparing an alloy semi-solid thixotropic blank by continuously extruding elementary substance mixed powder, and belongs to the technical field of material processing. According to the method, two or more kinds of elementary substance mixed powder is evenly mixed and conveyed into a groove of a continuous extrusion wheel, the powder in a female die is crushed, rubbed, extruded and welded to form a block material after passing through the female die, the block material is cut out according to the equal volume of a target part, heat preservation is carried out for a certain time near the melting point of low-melting-point elementary substance metal, the low-melting-point powder begins to melt, recovery recrystallization occurs in a welding area of the high-melting-point powder, and a semi-solid structure with a high-melting-point solid phase as a framework and a low-melting-point liquid phase distributed between is formed. According to the method, metal powder continuous extrusion and a strain-induced melting activation method are combined, the short-process and batch semi-solid alloy blank making method is achieved, the semi-solid thixotropic temperature of the alloy can be reduced, and energy consumption and the cost of a tool mold are reduced.

Description

technical field [0001] The invention relates to a method for continuously extruding elemental mixed powder to prepare alloy semi-solid thixotropic blanks, especially a method for efficiently and continuously preparing alloy semi-solid blanks while reducing the alloy semi-solid thixotropic deformation temperature, which belongs to materials field of processing technology. Background technique [0002] Semi-solid forming technology, referred to as SSM, has been widely concerned and deeply researched since it was pioneered by Professor M.C.Flemings of the Massachusetts Institute of Technology in the early 1970s. Compared with traditional casting, semi-solid forming technology has a certain volume fraction of solid phase in its liquid phase, which has small latent heat of crystallization and small solidification shrinkage. Therefore, the formed parts have compact structure, high mechanical properties, high dimensional accuracy, can realize near-net forming, have little thermal ...

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Problems solved by technology

[0003] The near-net shape technology of complex components of engineering application alloys such as aluminum, copper, nickel, iron, and titanium-based alloys is mainly developed around precision casting, especially the processing equipment for thin-walled parts is complex and expensive, the mold materials are special and the processing costs are high, and the process parameters Strict control and low yield lead to high cost; and the processing of its forgings is difficult to form complex structures at one time, requiring multiple processes such as turning and milling, the process is long and the cost is still high; semi-solid thixotropy can Parts with complex structures are obtained at one time, and the performance is close to that of forgings, but the semi-solid thixotropic deformation temperature of the alloy is mostly close to the liquidus line of the alloy, the deformation temperature is high, the high temperature insulation is difficult, the thermal shock to the mold is large, and special material molds are required.

Even some alloys have no solid-liquid interval, so semi-solid processing cannot be performed

Therefore, the promotion and development of semi-solid thixotropic forming technology of alloys is limited regardless of the high-temperature performance requirements and operational feasibility of tool and die materials; The method of thixotropic deformation temperature shortens the alloy semi-solid billet-making process, reduces the process window of semi-solid thixotropic deformation, reduces the cost of tool and mold materials, and improves the service life of the mold

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