R曲線法およびストレッチ・ゾーン幅法によるHT80, SM50Aおよび2017-T4のJIc破壊じん性評価

JIc tests were carried out on two steels and one aluminum alloy by means of the ASTM and JSME R-curve methods as well as the JSME streched-zone-width (SZW) method. The SZW method tended to overestimate the JIc values at initiation of ductile tearing. The ASTM method, which also had a tendency to overestimate these JIc values, seemed to be the most convenient and stable procedure among the three methods. The JSME R-curve method gave the smallest JIc values which were physically closest to the crack initiation.