Effect of Different Heat Treatments on Microstructure and Mechanical Properties of Ti6Al4V Titanium Alloy

This paper analyzed the microstructure of Ti6Al4V titanium alloy after different heat treatments. The tensile experiment and instrumented impact test were performed. The relationship among the microstructure, impact fracture characteristic and mechanical properties was analyzed by metallurgical microscope and environment scanning electron microscope (ESEM). Results show that the microstructure, mechanical properties and impact toughness of Ti6Al4V titanium alloy are affected by the solution and aging treatment. The yield strength and ultimate tensile strength are improved remarkably. The ductility increases firstly, and then decrease. The good comprehensive properties can be obtained when the Ti6Al4V titanium alloy is treated under the condition of 960 °C/1 h + WQ and 500 °C/4 h + AC. σ0.2 is 1050 MPa, σb is 1120 MPa and Ak is 46.22 J·cm−2. The microstructure of the titanium alloy after solution and aging treatment consists of the β matrix and the precipitation of the α-phase. The lamellar β-phase and the α-phase structure of the small needle plexiform can enhance comprehensive properties.