1216 Nano-Scale Strength Analysis by EBSD and AFM Hybrid Method in Ultrafine-Grained Copper Processed by ECAP
Details
Ultrafine-grained Cu processed by ECAP (Equal Channel Angular Pressing) with the grain size of d = 300 nm was fatigued at low stress intensity factor to investigate the grain coarsening mechanism during fatigue. EBSD (Electron Backscatter Diffraction) and AFM (Atomic Force Microscopy) methods were employed for the nanometer-scale analysis. The results show that fatigue damage area around the crack is observed in coarsened grains. Slip damages with the primary and secondary slip system were activated during fatigue. The detailed observation before and after fatigue at the same region revealed that the grain boundary of the coarsened grain moves as a high angle boundary. The initial residual strain in ECAP-processed Cu is considered to be one of the driving factors of the high angle boundary.
