时效温度对 TB8 钛合金动态力学性能的影响

TB8 (Ti-15Mo-2.7Nb-3Al-0.2Si) is a metastable β titanium alloy, which plays an important role in the aerospace field. Microstructure, strain and strain rate are three important factors affecting mechanical properties of TB8 titanium alloy. Based on a universal material testing machine and a split Hopkinson pressure bar (SHPB) device, the effect of solution and aging heat treatment process on mechanical properties of TB8 titanium alloy was studied. Optical microscope (OM) and scanning electron microscope (SEM) were used to characterize the microstructure and section morphology of the specimens before and after deformation. The results show that short strip α phase precipitates inside the alloy after solution and aging treatment, and the size and quantity of secondary phase increase with aging temperature increasing. Under different loading conditions, the strain rate strengthening effect of TB8 titanium alloy before and after heat treatment is obvious, but the strain strengthening effect is not obvious under dynamic loading condition. With the increase of aging temperature, the yield strength of the alloy decreases and the plasticity increases. The failure mode of specimens under dynamic loading is typical shear failure. Adiabatic shear band is the precursor of crack formation and specimen failure.