分离式霍普金森压杆加载下不同组织Ti-6321钛合金的动态响应行为

Ti-6321 titanium alloys with different microstructures were obtained through solution treatment, and the influence of microstructure on the dynamic behavior of materials was studied. An universal testing machine and a split Hopkinson pressure bar test device, combined with the characterization methods such as optical microscope and scanning electron microscope, were used to characterize the microstructure evolution of loaded titanium alloy sample. The results demonstrate that the alloys with equiaxed, bimodal and Widmanstatten microstructures have obvious strain rate strengthening effect, and the critical shear fracture strain rates are all 3 000 s^-1. The bimodal structure has good strength and plastic combination under static and dynamic compression, Widmanstatten structure is poor, and the equiaxed structure has higher critical shear strain and impact absorption energy, which are 0.252 and 307 MJ•m^-3, respectively. At the strain rate of 3 000 s^-1, the strain rate sensitivity factor of the equiaxed microstructure increases gradually, the strain rate sensitivity factor of Widmanstatten microstructure decreases, and the strain rate sensitivity factor of bimodal microstructure is unchanged with the increase in strain. When the strain is 5%, the strain rate sensitivity factors of equiaxed and bimodal microstructures increase with the increase in the strain rate, while the strain rate sensitivity factor of Widmanstatten microstrucutre is unchanged. Adiabatic shear failure occurs in all microstructures. Equiaxed structure has a low adiabatic shear sensitivity, and Widmanstatten structure has a high adiabatic shear sensitivity.