Study on Strain-compensated Physical Constitutive Relation of Laves Phase NbCr2/Nb Dual-phase Alloy

Abstract:

The Laves phase NbCr2/Nb dual-phase alloy has the potential of being used as a new high-temperature structural material due to its excellent high-temperature mechanical properties. It is known that the flow stress constitutive relationship reveals the hot deformation behavior of an alloy. In this paper, the strain-compensated physical constitutive relationship of Laves phase NbCr2/Nb dual-phase alloy with consideration of the effect of deformation temperature on the Young"s modulus and self-diffusion coefficient of the alloy is explored for the first time based on its isothermal constant strain rate compression experiment data at temperature of 1000-1200 °C and strain rate of 0.001-0.1 s-1. The results show that the correlation coefficient (R) and the average absolute relative error (AARE) of the strain-compensated physical constitutive relationship based on the creep index n=5 are 0.974 and 59.3% respectively, indicating that this physical constitutive model is not accurate for characterizing the flow stress behavior of the alloy. Whereas the R and the AARE of the strain-compensated physical constitutive relationship based on the variable of creep index n are 0.984 and 10.6% respectively, showing that this physical constitutive model can satisfactorily characterize the flow stress behavior of the alloy and the flow stress prediction accuracy of the physical constitutive model is higher than the traditional Arrhenius constitutive model.

Key words:Laves phase NbCr2/Nb dual-phase alloy; strain compensation physical constitutive model; creep index; self-diffusion coefficient; Young";s modulus