高温低サイクル疲労における粒界き裂伝ぱ特性への結晶粒径の影響

概要

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Effects of grain size on Intergranular crack propagation properties under low-cycle fatigue were investigated using austenitic SUS304 stainless steel at 973K in air. Wave shapes used were strain-controlled slow-slow and slow-fast triangular ones. Small crack propagation rate (SCPR) and large crack propagation rate (LCPR) were examined. The SCPR was lower in the specimens with a smaller grain diameter, and increased in proportion to about D^<0.7> in the tests with slow-slow and slow-fast wave shapes. The LCPR increased with the grain size in proportion to about D^<0.5> in the tests with slow-fast wave shape. In this type of wave shape, the main crack coalesced with the wedge-type cracks which were initiated at the front of the main crack. The dependence of LCPR on grain size was much the same as that of crack initiation life, as analysed by the authors.
社団法人日本機械学会の論文
1990-08-25