Constitutive behavior and processing maps of low-expansion GH909 superalloy
来源期刊：International Journal of Minerals Metallurgy and Materials2017年第4期
论文作者：Zhi-hao Yao Shao-cong Wu Jian-xin Dong Qiu-ying Yu Mai-cang Zhang Guang-wei Han
文章页码：432 - 443
摘 要：The hot deformation behavior of GH909 superalloy was studied systematically using isothermal hot compression tests in a temperature range of 960 to 1040°C and at strain rates from 0.02 to 10 s-1 with a height reduction as large as 70%. The relations considering flow stress,temperature,and strain rate were evaluated via power-law,hyperbolic sine,and exponential constitutive equations under different strain conditions. An exponential equation was found to be the most appropriate for process modeling. The processing maps for the superalloy were constructed for strains of 0.2,0.4,0.6,and 0.8 on the basis of the dynamic material model,and a total processing map that includes all the investigated strains was proposed. Metallurgical instabilities in the instability domain mainly located at higher strain rates manifested as adiabatic shear bands and cracking. The stability domain occurred at 960–1040°C and at strain rates less than 0.2 s-1; these conditions are recommended for optimum hot working of GH909 superalloy.
Zhi-hao Yao1,2，Shao-cong Wu1，Jian-xin Dong1，Qiu-ying Yu3，Mai-cang Zhang1，Guang-wei Han4
1. School of Materials Science and Engineering,University of Science and Technology Beijing2. The Fu Foundation School of Engineering and Applied Science,Columbia University3. Beijing Institute of Aeronautical Materials4. Department of High Temperature Materials Research,Central Iron and Steel Research Institute
摘 要：The hot deformation behavior of GH909 superalloy was studied systematically using isothermal hot compression tests in a temperature range of 960 to 1040°C and at strain rates from 0.02 to 10 s-1 with a height reduction as large as 70%. The relations considering flow stress,temperature,and strain rate were evaluated via power-law,hyperbolic sine,and exponential constitutive equations under different strain conditions. An exponential equation was found to be the most appropriate for process modeling. The processing maps for the superalloy were constructed for strains of 0.2,0.4,0.6,and 0.8 on the basis of the dynamic material model,and a total processing map that includes all the investigated strains was proposed. Metallurgical instabilities in the instability domain mainly located at higher strain rates manifested as adiabatic shear bands and cracking. The stability domain occurred at 960–1040°C and at strain rates less than 0.2 s-1; these conditions are recommended for optimum hot working of GH909 superalloy.
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