Effects of β Heat Treatment Cooling Methods on Microstructure and Impact Toughness of TC32 Titanium Alloy

Effects of four β heat treatment cooling methods, including furnace cooling（FC）, air cooling（AC）, force air cooling（FAC） and water quenching（WQ）, on the microstructure and room temperature impact toughness of new low-cost high performance TC32 titanium alloy were studied by using optical microscope（OM）, scanning electron microscope（SEM）, stereo microscope and pendulum impact testing machine. The results show that with increasing cooling rate, the size of α colony, αlamellar, α boundary and β lamellar, as well as the impact toughness properties, decrease dramatically. The relationships among cooling method, the microstructure, fracture mechanism and impact toughness properties were explored in explaining the change law of cooling methods on the microstructure and impact toughness.