Ti-6 Al-4 V合金の弾・塑性疲労き裂進展特性と低サイクル疲労寿命評価

概要

論文の詳細を見る
Ti-6 Al-4 V alloy annealed at 760℃ was low-cycle fatigued, and then strain-based fatigue life and the elastic-plastic fatigue crack growth were investigated. The Ti-6 Al-4 V alloy exhibited a significantly shorter crack initiation-and final failure-lives than did structural carbon and alloy steels when they were plotted against the plastic strain range, Δε_p. Meanwhile, the total strain-final failure life curves were situated on the short-life side in the high-strain regime and on the long-life side in the low-strain regime, respectively, compared with those of structural steels. There existed little difference in the crack growth rate, da/dN, plotted against cyclic J integral range, ΔJ, among Ti-6 Al-4 V alloy and structural carbon and alloy steels. The life spent for crack propagation, N_p, was successfully calculated by combining the da/dN-ΔJ relationship and the cyclic stress-strain response; the inflection behavior appearing in the log Δε_p-log N_p relationship was also satisfactorily assessed by the present calculations. Furthermore, the final failure life derived by using the crack initiation to final failure life ratio of N_i/N_f=0.20 was in good agreement with the test data.
一般社団法人日本機械学会の論文
1991-02-25