Effect of heat treatment on microstructure and properties of CMT arc additive deposited Inconel 625 alloy

doi:10.13251/j.issn.0254-6051.2024.10.004

Abstract

Abstract: Direct aging treatment (720 ℃×8 h＋620 ℃×8 h, air cooling) and solution treatment (950, 1000, 1100, 1200, 1250 ℃×1 h, water cooling) were conducted on the Inconel 625 alloy arc additive deposited by CMT (cold metal transfer). The effects of different heat treatment processes on the microstructure and properties of the deposited Inconel 625 alloy were analyzed by mechanical properties test, electrochemical potentiodynamic polarization test, optical microscope, field emission scanning electron microscope (SEM) and EDS. The results show that the effect of aging treatment on the Laves phase in the deposited alloy is not obvious. As the solution treatment temperature increases, the microstructure changes from deposited dendrites to equiaxed grains, and the harmful Laves phase dissolves and disappears. Aging treatment can significantly improve the hardness and tensile strength of the alloy, compared with that of the deposited state, the hardness and tensile strength are increased by 35.1 HV0.5 and 176.4 MPa, respectively, but the plasticity is reduced. Solution treatment at 1200 ℃ can significantly improve the plasticity of the alloy, compared with that of the deposited state, the percentage total extension at fracture is increased by 49.6%. Aging treatment has no obvious effect on the corrosion resistance of the alloy, but solution treatment at 1200 ℃ can significantly improve the corrosion resistance of the alloy as the self-corrosion potential increased by 22.8% and the self-corrosion current density reduced by 46.9% compared with that of the deposited state.

Key words: Inconel 625 alloy, heat treatment, microstructure, mechanical properties, corrosion resistance

CLC Number:

TG156

Jiang Ruixin, Han Guofeng, Niu Zongwei, Wang Wenyu, Huang Xiangyuan, Zhao Yang. Effect of heat treatment on microstructure and properties of CMT arc additive deposited Inconel 625 alloy[J]. Heat Treatment of Metals, 2024, 49(10): 25-30.

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