Abstract

The effect of warm rolling and three aging treatments on microstructure and mechanical properties of 7075 alloy was investigated via optical microscopy, electron backscattered diffraction, transmission electron microscopy and tensile tests. 7075 alloy was warm rolled and then were solution treated followed by three different aging processes viz., one-step, two-step and three-step aging. Results show that the ductility of 7075 alloy is improved during warm rolling and the strength increases with increasing total warm-rolled reduction. The average grain size decreases after aging compared with that in the solution state. The microstructure of the one-stage aged sample consists of elongated grains and equiaxed grains while almost completely equiaxed microstructure is obtained in solutionized, two-stage and three-stage aged samples. The distributions of dislocations, precipitates and grain refinement influence mechanical properties together. The one-stage aged sample possesses a combination of acceptable strength and excellent ductility. Two-stage and three-stage aged samples have higher elongations but lower strengths.

中文翻译：

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7075合金的温轧及轧后时效研究

摘要

采用金相显微镜、电子背散射衍射、透射电子显微镜和拉伸试验研究了温轧和三次时效处理对7075合金组织和力学性能的影响。7075 合金经过温轧，然后进行固溶处理，然后进行三种不同的时效处理，即一步、两步和三步时效。结果表明，7075合金的延展性在温轧过程中得到改善，强度随着热轧总压下量的增加而增加。与固溶状态相比，时效后平均晶粒尺寸减小。一级时效样品的微观结构由细长晶粒和等轴晶组成，而在固溶、二级和三级时效样品中获得几乎完全等轴的微观结构。位错、析出物的分布和晶粒细化共同影响力学性能。一级时效样品具有可接受的强度和出色的延展性的组合。两阶段和三阶段时效样品的伸长率较高但强度较低。