(大連理工大學 材料科學與工程學院，大連 116023)
摘 要: 對Hastelloy C-276合金分別在不同的溫度(750、800、850和900 ℃)和相應的初始應力(250、250、250和200 MPa)條件下進行了多組應力松弛試驗。利用試驗測得的應力松弛曲線推導出應力松弛過程中蠕變應變速率與應力之間的關系，建立用于描述Hastelloy C-276合金應力松弛行為的蠕變本構方程，通過對蠕變應變速率-應力曲線進行擬合，得到各溫度下蠕變本構方程中的材料常數(shù)。將蠕變本構方程帶入有限元軟件MSC.Marc對Hastelloy C-276合金的應力松弛過程進行模擬，模擬得到的應力松弛曲線與試驗測得的應力松弛曲線符合得很好，驗證蠕變本構方程的可靠性。
關鍵字: Hastelloy C-276合金；應力松弛試驗；蠕變本構方程；真空熱脹形
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
