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借助不同温度下的固溶处理,得到一系列具有不同溶质原子浓度及析出相含量的Al-4.5wt%Cu合金材料试件.比较这些试件在拉伸实验中的锯齿形屈服现象的时空特性,分析溶质原子与析出相对位错运动的影响,从而探究动态应变时效产生的微观机理.实验结果显示,当固溶处理温度由500℃逐步降低,应力-时间曲线上的应力锯齿跌落幅值逐渐减小,并在300℃时达到最小.继续降低固溶处理温度至100℃,应力锯齿跌落幅值又逐渐增大.同时,热处理方式的改变对剪切带的传播特性也有显著影响.实验发现,固溶处理温度高于300℃时,溶质原子对DSA的影响强于析出相;反之,固溶处理温度低于300℃时,析出相对DSA的影响强于溶质原子;室温下析出相是影响Al-4.5wt%Cu合金DSA机理的主要因素.
A series of Al-4.5wt% Cu alloy specimens with different concentrations of solute atoms and precipitated phases were obtained by solution treatment at different temperatures.The spatio-temporal characteristics of the zig-zagging yield phenomena of these specimens in tensile tests , The influence of solute atoms on the relative dislocation motion was analyzed to explore the microscopic mechanism of dynamic strain aging.The experimental results show that when the solution treatment temperature is gradually decreased from 500 ℃, the magnitude of stress sawtooth drop on stress-time curve Decreases, and reaches the minimum at 300 ℃ .At the same time, the change of the heat treatment method also has a significant effect on the propagation characteristics of the shear band, as the temperature of the solution treatment decreases to 100 ℃. When the solution treatment temperature is higher than 300 ℃, the effect of solute atoms on DSA is stronger than that of precipitation phase. On the other hand, when the solution treatment temperature is lower than 300 ℃, the effect of precipitation on DSA is stronger than that of solute atoms. Al-4.5wt% Cu alloy DSA mechanism of the main factors.