Composite extrusion mold and method for preparing block ultrafine crystal material

Abstract

The invention discloses a composite extrusion mold for preparing a block ultrafine crystal material. The composite extrusion mold comprises an extrusion male mold and an extrusion female mold, an extrusion channel is formed in the extrusion female mold, and is formed through in-sequence splicing of an inlet channel, a forward extrusion conical angle area, a forward extrusion work belt area and anoutlet channel, the extrusion male mold and the inlet channel are consistent in cross section, the cross sections are both in 1*w rectangles, the cross section of the forward extrusion work belt areais in a w*w rectangle, the forward extrusion conical angle area forms transition between the inlet channel and a forward extrusion work belt, the cross section shape of the outlet channel is the samewith that of the inlet channel, orientations are different, and the invention further discloses a method for preparing the block ultrafine crystal material. The composite extrusion mold and the methodcan combine forward extrusion and variable-cross-section corner extrusion, through reasonable control over the mold structure parameters, the cross section size of an extrusion blank is consistent with the size of a blank before extrusion, repeated extrusion of the blank can be achieved, and the material structure and the property can be optimized.

Description

technical field [0001] The invention relates to the technical field of extrusion forming of metal materials, in particular to a composite extrusion die and method for preparing bulk ultrafine-grained materials. Background technique [0002] Grain refinement is one of the important means to strengthen metal materials. At present, severe plastic deformation (SPD) technology has been proved to be an effective means of grain refinement. Generally speaking, the degree of severe plastic deformation mainly depends on the fact that the shape and size of the blank remain unchanged before and after deformation. Through repeated plastic deformation, the grains of the material are refined, and the bulk ultrafine grain (UFG) material is obtained, which improves the quality of the material. Comprehensive performance. Common severe plastic deformation techniques include equal-diameter angular extrusion (ECAP), high-pressure torsion (HPT), cumulative stack rolling (ARB), multi-directional ...

AI Technical Summary

Problems solved by technology

However, a common problem in the current composite extrusion technology based on forward extrusion is that the cross-sectional area of ​​the billet becomes smaller after extrusion, and repeated deformation cannot be performed. Therefore, it is mainly used for some materials with low deformation resistance.

However, due to the insufficient degree of deformation once or the inability to further refine the structure through repeated deformation, there are inhomogeneous structures and properties in some materials.

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