GH39合金拉伸应变硬化行为与断口形貌  

Tensile Strain Hardening Behavior and Fractography of Superalloy GH39

作　　者：王辉[1] 陈明和[1] 张成祥[1] 赵海艳[2] 王鹏飞[2] 雷晓晶 

机构地区：[1]南京航空航天大学机电学院,南京210016 [2]西安航空发动机集团有限公司,西安710021

出　　处：《航空材料学报》2016年第5期77-81,共5页Journal of Aeronautical Materials

摘　　要：采用不同应变速率(0.0001~0.1s^(-1))下单轴拉伸实验对GH39合金应变硬化行为与断口特征进行了研究。结果表明:应变硬化指数在不同应变量下表现出多重性,真应力应变不完全遵循Hollomon对数线性关系。塑性变形开始阶段,应变硬化指数n为恒定;真应变ε在0.014~0.13,n随着应变的增加而增加,在此过程由于形成大量形变孪晶,孪晶与位错相互作用,硬化能力增强;随着应变速率的提高,材料的应变硬化指数略下降;在低应变速率时段合金的拉伸断口为延性断裂,随着应变速率的增加从韧窝状延性断裂向半解理断裂过渡。The strain hardening behaviour and fractography of superalloy GH39 was investigated by tensile test at different strain rates. Results indicate that strain hardening behaviours are different during the deformation process. True stress-strain curve obeys the Hollomon relationship partly. The strain hardening exponentn in this stage is constant in the initial plastic stage. However, the value of n increased with true strain s increasing when true strain is between 0. 014 and 0. 13. A lot of deformation twinning can be found, the twins and dislocations worked together to increase the value of n. The strain hardening exponent is increased lightly with the strain rate increasing, SEM observations show that in the case of low strain rate, the fracture mode is typical ductile, but there is a tendency from ductile to brittle fracture with increasing the strain rate.

关 键 词：GH39合金 形变孪晶 应变硬化 应变速率 断口形貌 

分 类 号：TG146.15[一般工业技术—材料科学与工程]