In the present work, the cyclic deformation behavior of Cu single crystals oriented for double and multiple slip as well as Cu bicrystals and tricrystals was investigated under constant plastic strain control at room ...In the present work, the cyclic deformation behavior of Cu single crystals oriented for double and multiple slip as well as Cu bicrystals and tricrystals was investigated under constant plastic strain control at room temperature in air. The main objectives of the study are : (1) to find out the effects of crystallographic orientation and grain boundary (GB) on the cyclic stressstrain(CSS) curves, (2) to compare the cyclic deformation behavior of the double-, multiple-slip crystals, bicrystals and tricrystals with that of singie-slip oriented crystals and to correlate the results with those of polycrystals; (3) to examine the corresponding dislocation structures; (4) to investigate the interactions of persistent slip bands (PSBs) with GBs and triple joint (TJ) as well as intergranular fatigue cracking in Cu bicrystals and tricrystals.展开更多
State Key Laboratory for Fatigue and Fracture of Materials, Institute of Metal Research, Chinese Academy of Sciences,Shenyang, 110015, China)Abstract:The cyclic saturation dislocation patterns within grains and in the...State Key Laboratory for Fatigue and Fracture of Materials, Institute of Metal Research, Chinese Academy of Sciences,Shenyang, 110015, China)Abstract:The cyclic saturation dislocation patterns within grains and in the vicinity of low-angle grain boundaries in fatigued copper crystal were successfully observed by electron channeling contrast technique in SEM. The results show that the dislocation patterns within grains consisted of typical two-phase structure, i.e. persistent slip bands (PSB) and veins. With increasing plastic strain amplitude (γp1 ≥1.7×10-3), large amount of PSBs and regufar dislocation walls were observed.The dislocation walls and PSBs could cross through the low-angle grain boundaries continuously except that the dislocation-free zone (DFZs) appeared at some local regions. Combining with the cyclic stress-strain response and dislocation patterns, the effect of low-angle grain boundaries on cyclic deformation behavior was discussed.展开更多
文摘In the present work, the cyclic deformation behavior of Cu single crystals oriented for double and multiple slip as well as Cu bicrystals and tricrystals was investigated under constant plastic strain control at room temperature in air. The main objectives of the study are : (1) to find out the effects of crystallographic orientation and grain boundary (GB) on the cyclic stressstrain(CSS) curves, (2) to compare the cyclic deformation behavior of the double-, multiple-slip crystals, bicrystals and tricrystals with that of singie-slip oriented crystals and to correlate the results with those of polycrystals; (3) to examine the corresponding dislocation structures; (4) to investigate the interactions of persistent slip bands (PSBs) with GBs and triple joint (TJ) as well as intergranular fatigue cracking in Cu bicrystals and tricrystals.
文摘State Key Laboratory for Fatigue and Fracture of Materials, Institute of Metal Research, Chinese Academy of Sciences,Shenyang, 110015, China)Abstract:The cyclic saturation dislocation patterns within grains and in the vicinity of low-angle grain boundaries in fatigued copper crystal were successfully observed by electron channeling contrast technique in SEM. The results show that the dislocation patterns within grains consisted of typical two-phase structure, i.e. persistent slip bands (PSB) and veins. With increasing plastic strain amplitude (γp1 ≥1.7×10-3), large amount of PSBs and regufar dislocation walls were observed.The dislocation walls and PSBs could cross through the low-angle grain boundaries continuously except that the dislocation-free zone (DFZs) appeared at some local regions. Combining with the cyclic stress-strain response and dislocation patterns, the effect of low-angle grain boundaries on cyclic deformation behavior was discussed.
