| Title |
Low Stress Deformation in the Early stage of Fatigue and Creep |
| Authors |
최승주(S . J . Choe); 남수우(S . W . Nam) |
| Abstract |
Correlation between Schmid factor and slip band formation under cyclic and static load was studied with 1.7∼3㎜ coarse grained aluminum(purity:99.999%) and corresponding dislocation structure was also discussed. Back reflection Laue method was used to obtain the orientation and Schmid factor of each grain. Applied creep stress was 240ｇr/㎟ and applied fatigue stresses were between 190∼340ｇr/㎟ and 21.5ｇr/㎟. As the value of Schmid factor of a grain was increased, the number of fatigue cycles, in which slip bands were formed, was decreased generally, but its grain size and orientation of neighbor grain seemed to affect the formation of slip band. In creep such relation did not exist and slip bands were fine and narrowly spaced in comparision with that of fatigue. With increasing the upper stress, slip band broadening became more prominent and under fatigue test between 220ｇr/㎟ and 30ｇr/㎟, cell structure was observed in the particular grain after 6×10⁴cycles. |