Effect of annealing temperature on the microstructure and mechanical properties of laser melting deposited TC31 high temperature titanium alloy
In order to improve the mechanical properties of laser melting deposition(LMD)TC31 high-temperature titanium alloy,the influence of annealing temperature on the microstructure evolution and mechanical properties was studied by using OM,SEM,TEM and mechanical property tests.The results revealed that the primary α phase content decreases with the increase in annealing temperature during single-stage annealing.The dissolution mainly occurs above 950 ℃,and then its content is only 29％at 980 ℃ after annealing.When the annealing temperatures exceeds 930 ℃,the width of the primary α phase dendrites significantly increases.As the annealing temperature increases,the size of the(Ti,Zr)6Si3 phase precipitated at the α/β interface increases and enters the interior of the α lamellae.The room-temperature yield strength tends to decrease with increasing annealing temperature when the alloy is annealed at 800 ℃ to 1 000 ℃.Due to the factors such as the growth of aggregated precipitates at phase interfaces and the increase in the size of αphase dendrites,the high-temperature yield strength of the alloy firstly decreases and then increases with increasing annealing temperature during annealing.The alloy exhibits excellent high-temperature mechanical properties after annealing at 1 000 ℃,with a tensile strength of 657 MPa,yield strength of approximately 466 MPa,and an elongation of 27％at 650 ℃.
high-temperature titanium alloyslaser melting depositionmicrostructure and property regula-tionhigh temperature mechanical propertiesannealing
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