SUS 321 綱のクリープ損傷様式とクリープ疲労相互作用との関連

概要

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In order to investigate the relationship between creep-fatigue interaction and creep damage mode of SUS 321 fine- and coarse-grained steels, the combined creep-fatigue loading tests were conducted. The creep damage, φ_c, and the fatigue damage, φ_f, which were accumulated till rupture in these tests were calculated using a linear life fraction damage rule. The φ_c vs. φ_f relation obtained was described by the following equation: (φ_c-φ_<c0>)+α[(φ_c-φ_<c0>)(φ_f-φ_<f0>)]^<0.5>+(φ_f-_<f0>)=1 where the falues of φ_<c0>, φ_<f0> and a depend on the creep damage mode corresponding to the creep loading condition in the combined creep-fatigue loading test. For the creep loading condition corresponding to transgranular fracture mode in creep test, the φ_c vs. φ_f relations of fine- and coarse-grained materials showed a convex form, but the value of φ_<c0> was different between these two materials. The value of φ_<c0> was dependent on cyclic hardening and softening behaviours of the materials under fatigue loading and on the sensibility of intergranular fracture of the materials tested. The φ_c vs. φ_f relation became φ_c + φ_f〜1 under the fracture mode condition where the micro cracks were formed along the grain boundaries and the surface crack propagated through the micro cracks.
社団法人日本材料学会の論文
1993-01-15