Refinement and Coarsening of Grains Caused by Tensile-Shear Tests in Ultra-Fine Grained Cu Processed by Severe Plastic Deformation

Abstract

Ultra-fine grained pure copper fabricated by equal-channel angular pressing was used as a sample. We made tensile-shear tests using specimens with notches cut from the sample and large shear deformation occurred between the notches. Microstructural changes between the notches caused by the large shear deformation were observed. Using micro scale lattices scribed on the surface of the specimen, we found both refinement and coarsening of grains caused by the large shear deformation. Although severe plastic deformation causes ultra-fine grained structure, it is known there is a limit of the grain refinement. The grain coarsening observed in the present study is considered to be the reason of the limit of the grain refinement caused by severe plastic deformation.

 

This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 82 (2018) 442–448.

Fig. 8 Changes of IPF maps for the same region before and after deformation: (a) γ_g = 0; (b) γ_g = 0.39; (c) γ_g = 0.67. The misorientations inside grains “d” and “e” at (d) γ_g = 0 and grain “d” at (e) γ_g = 0.39 and (f) γ_g = 0.67 are measured by line scanning of the black lines in the IPF maps.