Mo-Nb单晶的热变形行为及本构方程

Hot Deformation Behavior and Constitutive Equation of Mo-Nb Single Crystals

摘要:

Gleeble-3800热模拟试验机对Mo-Nb单晶材料的高温流变应力变化规律进行了热模拟实验研究，变形温度区间为1100~1350℃、应变速率为0.001~10s-1、变形程度为50%，真应变量为0.7。结果表明，变形温度和变形速率对Mo-Nb单晶材料的流变应力对有较大影响，Mo-Nb单晶材料的真应力-真应变曲线表现出峰值、应变软化和稳态流动等特征。采用修正Arrhenius双曲正弦函数建立了Q、A、n、α等材料常数与真应变的函数关系式，计算了在试验条件下的各种材料参数，推导了Mo-Nb单晶材料高温变形本构方程。

Abstract:

Isothermal compression of the Mo-Nb single crystals was conducted on a Gleeble-3800 thermal simulator at the deformation temperature range of 1100-1300℃with strain rates ranging from 0.001 to 10s-1 and height reduction of 50%, true strain is 0.7. The results show that the deformation temperature and strain rates affected the flow stress during the thermal deformation of Mo-Nb single crystals significantly. The true stree-strain curves exhibit a peak flow stress, flow softening and steady flow behavior. The constents of Mo-Nb single crystals, such as the activation energy Q, the stress exponent n, are calculated. The constitutive equation is estabilished based on a hyperbolic-sine equations of Arrhenius type.