Early-stage α-phase and Ti2Cu Phase Formation in a Ternary Ti-V-Cu Alloy

摘要

The early-stage precipitations of α-phase and Ti2Cu intermetallic compound have been characterized in a ternary Ti25V-3Cu alloy. Using aberration-corrected scanning transmission electron microscopy (STEM) and three-dimensional atom probe (3DAP).detailed examination of the crys-tallographic structures and compositional partitioning of the nucleation sites was carried out. These techniques have enabled accurate phase identifications of precipitate embryos having a size in the nanometer range,and the geometrical arrangement of the different phases. The results indicate that the α and the intermetallic compound tend to form a mutually-conjugated structure governed by a specific orientation relationship. Upon continued isothermal aging, twin related variants of both phases develop in the β matrix.