高温での銅材の衝撃疲労強度とその疲労過程におけるサイクリッククリープ塑性変動挙動

概要

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The impact fatigue tests for oxygen-free copper and high strength copper were carried out at various temperatures between 100 and 250℃ as well as at room temperature. The fatigue strength and plastic deformation due to cyclic creep under impact tensile loads were analyzed in consideration of temperature-dependence and static tensile properties. The impact fatigue strength was found to be expressed by the formula of σ(N_fT)^m_0=D_0, where m_0 and D_0 are the material constants for impact fatigue strength at each high temperature T_θ(K). The values of m_0 and D_0 depended on the temperature and were expressed by the formulas of m_0= m_0^*+m_1^*( T_θ-273) and D_0=D_0^*exp(Q/κt_θ). The behavior of cyclic creep plastic deformation was expressed by a formula including only plastic strain ε_p and normalized number of cycles N/N_f, which is independent of impact stress σ, duration time T and temperature T_θ.The values of m_0, D_0 and main material constants (a_l, a_2), duration time T and temperature Ta-which appear in the formula expressing the cyclic deformation, had distinct relationships with the ultimate strength σ_B, reduction of area φc and elongation δ in static tension. Impact fatigue strength and cyclic creep plastic deformation at high temperatures can be well estimated through these relationships from the static tensile properties at room temperature.
社団法人日本材料学会の論文
1987-06-15