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通过拉伸试验研究了GH690合金从298～623K的变形行为,用光学显微镜、扫描电镜和透射电镜观察了变形组织。结果表明,合金在298K拉伸时能够通过孪生协调变形,生成的形变孪晶阻碍了位错的滑移,从而使合金获得了较高的加工硬化速率,导致合金的强度和塑性较高。随着形变温度的升高,合金通过孪生协调变形的能力降低,变形机制由孪生转变为滑移,滑移产生的加工硬化效应小于孪生,因此合金的强度和塑性随之降低。
The deformation behavior of GH690 alloy from 298 to 623 K was studied by tensile test. The deformation of GH690 alloy was observed by optical microscope, scanning electron microscope and transmission electron microscope. The results show that the alloy is able to deform through twins at 298K and the deformed twin prevents the dislocation slippage, resulting in a higher work-hardening rate of the alloy resulting in higher strength and ductility of the alloy. As the deformation temperature increases, the ability of the alloy to deform through twin deformation decreases, and the deformation mechanism changes from twin to slip. The work hardening effect caused by slippage is smaller than that of the twin, so the strength and ductility of the alloy decreases.