A Review of Creep Deformation and Rupture Mechanisms of Cr-Mo Alloy for the Development of Creep Damage Constitutive Equations under Lower Stress

This paper presents a review of creep deformation and rupture mechanisms of low Cr-Mo alloy for the development of its creep damage constitutive equations under lower stress. The most popular Kachanov-Robatnov-Hayhurst (KRH) formulation was not necessarily developed and calibrated for low stress and cannot depict the creep strain accurately under multi-axial state of stress due to the three-dimensional generalization method used. This paper summarizes a critical analysis on the cavity nucleation and growth, and the deformation mechanisms and creep damage evolution characteristics at the temperature ranging for 723K to 923K (450°C to 650°C), particularly under low stress level (0.2-0.4 ), in order to form the physical base for the development of creep damage constitutive equation. Moreover, it covers the influence of the stress level, states of stress, and the failure criterion.