Effect of Sample Size on Microstructure and Mechanical Properties of OFHC Copper Processed by Equal Channel Angular Pressing

Abstract

The potential of scaling up the industrial applications of the Equal Channel Angular Pressing using large square billets (d=32 mm and 12 mm) was investigated by experiment on oxygen-free high-conductivity (OFHC) copper. The microstructure of the intermediate deformation zone between zero-pass and one-pass of ECAP was characterized by EBSD, and the distribution of microhardness was also given to analyze the deformation region. The results show the width of inhomogeneous deformation zone is proportionate to sample size. The texture evolution during first pass of ECAP was investigated, and ideal components of simple shear textures were developed. After multi-pass of ECAP there was no obvious difference of microstructures (TEM) and mechanical properties between them. Strain and strain rate distributions were given by experiments. It is found that changing the absolute size of the sample does not change strain distribution in the deformation zone significantly, and so to the strain rate distribution when the absolute pressing speed changes proportionally to the sample size.