期刊
ISIJ INTERNATIONAL
卷 63, 期 2, 页码 354-365出版社
IRON STEEL INST JAPAN KEIDANREN KAIKAN
DOI: 10.2355/isijinternational.ISIJINT-2022-340
关键词
nickel-based superalloy; flow curve; constitutive equation; strain-induced dynamic precipitation; dynamic recrystallization; hot forming
This study aims to formulate a constitutive equation to accurately determine the flow stress of superalloy 718 for effective production of gas turbine disks. A hot-compression test was conducted to analyze the flow stress in the dynamic precipitation region. A new constitutive equation for the generalized flow curve of superalloy 718 was obtained by considering these metallurgical phenomena.
This study aims to formulate a constitutive equation to accurately determine the flow stress of superalloy 718 for effective production of gas turbine disks. A hot-compression test with superalloy 718 at temperatures ranging from 900 to 1 000 degrees C, a reduction rate of 67%, and strain rates of 0.1, 1, and 10 s(-1), respectively, was conducted to analyze the flow stress in the dynamic precipitation region. An accurate flow stress curve was obtained for each strain rate and initial temperature. The flow curves obtained at a deformation temperature of 900 degrees C and strain rates of 0.1 and 1 s (-1), represent a combination of workhardening and dynamic recovery. Dynamic recrystallization (DRX) behavior was observed under other deformation conditions. At a deformation temperature of 950 degrees C and each strain rate, the strain at the onset of DRX (epsilon(c)) decreases, and DRX tends to occur rapidly. In addition, the steady-state stress at a strain rate of 1 s (-1) was greater than that at a higher strain rate of 10 s (-1). The lowest steady-state stress among all the experimental conditions was observed at a strain rate of 10 s (-1). This may be attributed to the role of nucleation sites, precipitation hardening caused by dynamically precipitated. phases at approximately 950 degrees C and a strain rate of 1 s (-1), and dynamic softening effects due to significant heat generated by deformation at a strain rate of 10 s (-1). A new constitutive equation for the generalized flow curve of superalloy 718 was obtained by considering these metallurgical phenomena.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据