巨大ひずみ加工により作製された超微細粒銅の引張せん断試験での結晶粒の微細化と粗大化

抄録

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.

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 misorientation inside the grains “d-e” at （d） γ_g＝0 and the grain “d” at （e） γ_g＝0.39 and （f） γ_g＝0.67 were measured by line scanning of the black lines in the inverse pole figure maps.