一种面心立方合金的流变应力及应变速率敏感性的表象模型及其计算机模拟

在Ｒ．Ｅ．Ｒｅｅｄ－Ｈｉｌｌ提出的体心立方合金塑性变形总流变应力的物理模型的基础上，建立了一种置换式面心立方合金Ｃｕ—３．１ａｔ．％ Ｓｎ的总流变应力的表象模型．此总流变应力由三项组成，即内应力、有效应力及由于动态应变时效所引起的应力．有效应力和应变速率及温度成指数函数关系．动态应变时效应力遵循修正了的Ｈａｒｐｅｒ关系式．内应力则被假定为以和弹性模量同样的规律随温度而改变．将此模型输入计算机进行模拟计算，所得结果和实验数据吻合很好，说明此模型成功地描述了在７７Ｋ至６００Ｋ温度范围内，合金的总流变应力和应变速率敏感性随温度的变化规律．

A Phenomenological Model of the Flow Stress' and Strain-Rate Sensitivity of an fcc Alloy With Its Computer Simulation

Based on the Physical model of the flow stress of a plastically deformed bcc alloy proposed by R. E. Reed-Hill, a phenomenological model of the total flow stress of an fcc alloy was set up according to the experimental measurements of flow stress and strain-rate sensitivity of Cu-3.1at. % Sn alloy. The total flow stress is composed of three components including an internal stress, an effective stress and a stress resulting from dynamic strain aging. The effec- tive stress was assumed to be related to the strain rate and the temperature by a power law, the dynamic strain aging component to obey a modified .Harper's relationship, and the internal stress to vary with the temperature by the same rule as that of young's modulus. The model was sent to the computer for simulating and found that it could successfully describe both the total flow stress and the strain-rate sensitivity of at least up to 500K.