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 KRH (Kachanov-Robatnov-Hayhurst) formulation was not necessarily developed and calibrated for low stress and can not 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 723 K to 923 K (450 °C to 650 °C), particularly under low stress level (0.2-0.4ογ) 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.