动高压加载条件下Ti-6Al-4V和Ti-47Nb合金 层裂微结构特征与断裂机理

Spall microstructure characteristics and fracture mechanism of Ti-6Al-4V and Ti-47Nb alloys were studied by plate impact experiments and “sample soft-capture” technology under the dynamic high-pressure loading, as well as microscopic analyses using optical microscopy and scanning electronic microscopy. The results indicate that Ti-6Al-4V alloy has stronger ability of spall resistance than Ti-47Nb alloy because of the high strength of Ti-6Al-4V alloys. The micro-voids in the spalled Ti-6Al-4V alloy almost nucleate at the α/β phase boundaries and propagate along the phase boundaries, and the micro-cracks of Ti-47Nb alloy are directly connected through micro-voids. Subsequently, the adiabatic shear band (ASB), which forms between macroscopic voids or main cracks, promotes the spall fracture of samples. Ti-6Al-4V and Ti-47Nb alloys fracture with ductile characteristics.