アルミニウム非等軸双結晶の結晶粒界影響部における疲れき裂の発生について

抄録

Fatigue tests on nonisoaxial aluminum bicrystals were carried out under such conditions as the rate of cycles 30.4 Hz and the maximum strain on the surface of specimen 0.16 to 0.19% using a Shenk type bending fatigue machine newly devised. A primary fatigue crack initiates at the crystal boundary affected-regions or at the notch of specimens. In the former cracking initiation, the value of N_ij between primary slip systems in two components crystals is small, and dislocations parallel to the crystal boundary plane in these slip systems or those in either one of component crystal have more screw component than edge one. While in the latter cracking initiation, the value of N_ij is large, and those dislocations have more edge component than screw one. It appears that plastic and elastic strain compatibilities are not a dominant factor causing fatigue cracks to initiate at the crystal boundary affected-regions, but may have a possibility of promoting the initiation of fatigue crack in the crystal boundary affected-resions.