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本文系统研究了Cu-Zn-Al形状记忆合金中形变度对形状回复的影响。从马氏体变态再取向的微观模型出发,阐明了预变形度ε对形状回复率η的影响规律及其本质。存在一个临界变形度ε_L(～2％),当ε<ε_L时,η随ε呈线性地增加(η=K_1ε-K_2d~(-1/2)),当ε>ε_L时,η随ε的增大而下降。同时讨论了拉伸变形与弯曲变形间的对应关系,得出弯曲变形时欲获最佳回复率的临界曲率半径R_L≈12mm。从热力学出发导出形状开始回复温度与变形度的关系T_s=A_s+(-1/2E_1ε~2+E_2ε)/ΔS_Tβ_1→M。所导出的定量规律,均与实验结果相吻合。
This article systematically studied the Cu-Zn-Al shape memory alloy deformation degree on shape recovery. Based on the microscopic model of metamorphism and reorientation of martensite, the influence regularity and essence of the shape deformability ε on the shape recovery rate η were clarified. There exists a critical deformation degree ε_L (~ 2%), η increases linearly with ε (η = K_1ε-K_2d -1/2) when ε <ε_L, and ε increases with ε Increase and decline. At the same time, the corresponding relationship between tensile deformation and bending deformation was discussed, and the critical radius of curvature R_L≈12mm for the best recovery rate was obtained. From the thermodynamic derivation of the shape to start the relationship between the temperature and the deformation of the response T_s = A_s + (- 1 / 2E_1ε ~ 2 + E_2ε) / ΔS_Tβ_1 → M. The quantitative rules derived are consistent with the experimental results.