Microstructure and Properties of Laser Additive Remanufactured IN718 Alloy Treated with Different Aging Temperatures

Abstract:

The effects of aging treatment on the microstructure and properties of laser additive remanufactured IN718 alloy were studied. The results show that the aging treatment can not change the epitaxy growth structure of laser additive remanufactured IN718 alloy, but it will affect the content and morphology of Laves phase. With increase of the aging time, γ phase gradually grows up and changes to δ after holding for a certain time at different aging temperatures. The higher aging temperature, the shorter the time required. In addition, the microhardness and tensile strength of the repaired zone increase firstly and then decrease with holding time at different aging temperatures. The peak value of microhardness is 410 HV_0.2 at 720 ℃ for 16 h, 385 HV_0.2 and 361 HV_0.2 at 760 ℃ and 800 ℃ for 4 h, respectively. The maximum values of tensile strength corresponding to different aging time at 720 ℃, 760 ℃ and 800 ℃ are 1153 MPa, 1090 MPa and 1026 MPa, respectively.

Key words:aging treatment; laser additive remanufacturing; IN718; microsturcture; tensile property