利用Gleeble--1500热模拟机、金相以及透射电镜对Cu--0.23%Al2O3(体积分数)合金高温塑性变形过程中的流变应力和显微组织变化规律进行了研究. 研究结果表明, Cu--0.23%Al2O3合金在热压缩过程中,热压缩条件不同流变应力变化规律会有所差异. 此外, 还求得了该合金高温变形的平均激活能和其他相关材料常数, 据此建立了峰值屈服应力--应变速率--温度之间的本构方程. 随热压缩温度的升高, 基体内动态再结晶晶粒尺寸和数量不断增加, 而在同一温度压缩时, 随应变速率的增加,组织分布不均匀性有所增加, 亚晶尺寸不断减小, 位错密度先增加后降低.
In order to deeply understand the high temperature deformation behaviors of Cu–0.23%Al2O3 (volume fraction) alloy, the changes of flow stress and microstructure for this alloy after deformation at high temperatures were investigated by using the Gleeble–1500 hot simulator, metallographic microscope and transmission electron microscope. The results show that the flow stress will change significantly with the thermal compression conditions and is mainly divided into three different stages. In addition, the average activation energy and other material parameters of this alloy deformed at high temperatures were obtained, based on them, the constitutive equation of the peak value yield stress–strain rate–temperature was also established. With increasing of compression temperature, the size and number of dynamic recrystallization grains are increased. However in the case of isothermal compression, with increasing of strain rates, the evolution of metallographical microstructures becomes disequilibrium, the size of subgrain is gradually decreased to about 0.5—1 μm, and the dislocation density is increased at first, and then decreased.
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