(大连理工大学 材料科学与工程学院，大连 116023)
摘 要: 对Hastelloy C-276合金分别在不同的温度(750、800、850和900 ℃)和相应的初始应力(250、250、250和200 MPa)条件下进行了多组应力松弛试验。利用试验测得的应力松弛曲线推导出应力松弛过程中蠕变应变速率与应力之间的关系，建立用于描述Hastelloy C-276合金应力松弛行为的蠕变本构方程，通过对蠕变应变速率-应力曲线进行拟合，得到各温度下蠕变本构方程中的材料常数。将蠕变本构方程带入有限元软件MSC.Marc对Hastelloy C-276合金的应力松弛过程进行模拟，模拟得到的应力松弛曲线与试验测得的应力松弛曲线符合得很好，验证蠕变本构方程的可靠性。
关键字: Hastelloy C-276合金；应力松弛试验；蠕变本构方程；真空热胀形
its creep constitutive equation
（School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023, China）
Abstract:The stress relaxation tests of Hastelloy C-276 alloy were conducted at different temperatures (750, 800, 850 and 900 ℃) and corresponding initial stress levels (250, 250, 250 and 200 MPa), respectively. Based on the experimental stress relaxation curves, the relationship between creep strain rate and stress was derived. Then, a set of creep constitutive equations were built for Hastelloy C-276 alloy and the material constants of these equations were determined by fitting the creep strain rate-stress curves. The creep constitutive equations were used to simulate the stress relaxation process of Hastelloy C-276 alloy by integrating these equations into finite element software MSC.Marc. The simulated stress relaxation curves agree well with the experimental ones, which verify the reliability of the creep constitutive equations.
Key words: Hastelloy C-276 alloy; stress relaxation test; creep constitutive equation; vacuum hot bulge forming
