Method for determining grain size in equal channel angular pressing technology

Abstract

It's a method to determine the grain size in established channel angular extrusion process. First, analyze the displacement of finite element in established channel angular extrusion process, determine the node displacement through the center differential, compute the strain through the relationship between strain and displacement, get the stress in according to the elastic constitutive relationship, map to the grain slide project and line to get the crystal grain the shear stress within the grain and on the boundary, compute the shear stress within the crystal grain and on the boundary, if not exceed the critical shear stress, the grain size is not changed, or compute the new dislocation density and grain size; according to the dislocation coupled differential equations determine the dislocation density increment within the grain and on the boundary from corresponding shear strain rate, updating the dislocation density, and compute the grain size in current state through the dislocation density. The invention can get the grain size of extrusion material in repeated multiple times deformation processes, and provide the corresponding angle grain size extrusion, extruded times and other design parameters references to extrusion technology.

Description

technical field [0001] The invention relates to a method in the technical field of plastic processing, in particular to a method for determining the grain size in an equal diameter angular extrusion process. Background technique [0002] The Equal Angular Extrusion process is a new type of plastic processing technology that refines the grains through extreme plastic deformation to obtain ultra-fine-grained metal materials. The high dislocation density subgrains formed in the process of equal angular extrusion gradually develop into ultrafine grains with high angle grain boundaries under the action of shear force, and experience the transformation from coarse grains to microcrystalline and nanocrystalline grains. process. It is very important to quantitatively grasp the evolution law of grain size from large to small during the process of equal angular extrusion deformation, which is very important to guide the process design of equal angular extrusion. At present, the grai...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to propose a method for determining the grain size in the equal angular extrusion process, so that it can obtain multi-pass repeated The grain size of the material in the extrusion deformation process provides the design basis for the extrusion process parameters such as extrusion angle and extrusion pass of the corresponding grain size for the equal diameter angular extrusion process

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