不同组织 Ti6321 钛合金在低温高应变速率下的变形和断裂行为

To close the research gap on marine titanium alloys at low temperatures and high strain rate rates, Ti6321 titanium alloys with three structures are prepared through heat treatment. The deformation and fracture behaviors of the three alloy samples within the temperature range of-80-25 °C and strain rate range of 2 500-3 500 s ^-1 are studied. A low-temperature split Hopkinson pressure bar is used for loading. The evolution of the microstructure is observed and analyzed by an optical microscope and scanning electron microscope. The results show that the strength of Ti6321 titanium alloy increases and the plasticity decreases as the temperature declines. The bimodal structure has good strength and plasticity matching at room temperature. With the decrease of temperature, the equiaxed structure has higher strength and better low-temperature plastic deformation capability, and shows good low-temperature dynamic compression properties. The study of the alloy's fracture mechanism shows that the equiaxed and bimodal structures exhibit typical ductile fracture characteristics. The fracture of Widmanstatten structure is an uneven cleavage surface, which has an evident tendency to brittle fracture.