Spall damage of TiNb alloys under Taylor-wave loading

摘要

Spall damage of two cast TiNb binary alloys, Ti75Nb25 and Ti50Nb50, is investigated under Taylor-wave loading at different impact velocities. The dynamic yield stresses are similar for both alloys (similar to 1.2 GPa). The incipient spall strength of Ti75Nb25 (3.2 GPa) is considerably lower than that of Ti50Nb50 (4.3 GPa). The damage in Ti75Nb25 is ductile in nature, and abundant {332}(113) deformation twins are activated. For Ti50Nb50, only a small amount of {112}(111) deformation twins are observed, and cracks are along grain boundaries or along the {112} planes in a grain interior, leading to the typical brittle spall failure. Spall strength, and deformation and damage modes of TiNb binary alloys depend on chemical compositions.