Fatigue-induced HCP-to-FCC phase transformation assisting crack nucleation of pure zirconium in high cycle fatigue regime

Fatigue-Induced HCP-to-FCC Phase Transformation Resulting in Two FCC-Zr Variants in Pure Zirconium

“…In summary, in order to effectively accommodate plastic deformation, a phase transformation occurs during the loading process, leading to a certain degree of improvement in the material's plasticity and strength. However, because of the accumulation of plastic deformation, stress concentration and strain mismatch can occur at corresponding interfaces, inducing the initiation of fatigue cracks and thereby affecting the material's fatigue performance [21]. In Figure 5b, the red region represents the matrix of the HCP-Zr phase, while the blue region represents the FCC-Zr phase.…”

“…Obviously, Zr experiences plastic strain accumulation and fatigue damage. Our previous research shows that cyclic loadings induce the appearance of the FCC-Zr phase [ 21 ], indicating that the in-service Zr may not be a single-phase material but a potential dual-phase material. This could potentially have an impact on the fatigue performance of the material.…”