Spall damage of TiNb alloys under Taylor-wave loading

Abstract

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 (∼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.