Near-linear elastic deformation behavior of a novel Zr-Ti-Nb-Sn alloy with multi-phase microstructures of beta, a? and a' phases

In this work, a multi-phase Zr-30Ti-7Nb-4Sn alloy with large near-linear elastic deformability was prepared by the solution treatment plus pre-straining (STP) treatment, and the underlying mechanism accountable for the near-linear elastic deformation was systematically clarified. It was found that the Zr-30Ti-7Nb-4Sn alloy was composed of beta, alpha '' and alpha ' phases, and numerous dislocations were formed in the alloy specimen after STP treatment. With the retarding effect of high-density dislocations, the stress-induced martensitic (SIM) transformation from beta to alpha '' phases took place homogeneously and continuously during loading, in conjunction with the occurrence of elastic deformation of beta, alpha '' and alpha ' phases. Under the entire tensile procedure, no observable phase transformation occurred between alpha ' martensite and beta phase. Consequently, the near-linear elastic deformation capability in STP Zr-30Ti-7Nb-4Sn alloy is mainly ascribed to the coupling actions of consecutive beta -> alpha '' SIM transformation and intrinsic elastic deformation of beta, alpha '' and alpha ' phases. These experimental results provide a basis for designing and developing novel multi-phase Zr-based alloys that possess large near-linear deformability.