Effect of water quenching temperature on microstructure and tensile properties of IN718 coatings during heat treatment

To enhance the strength and toughness of laser-clad IN718 coating on a 27SiMn steel surface, the heat treatment process of "heating + water quenching + natural cooling+ tempering+ natural cooling" was used. Keeping other parameters unchanged, different water quenching temperatures were used to heat treat the forming IN718 coatings. The properties of IN718 coatings after heat treatment were analyzed. The results show that with the increase of water quenching temperature, the elemental distribution of the coating is more uniform, the elemental diffusion tends to be stable, and the organization grain size of the coating is gradually reduced. The mechanical strength of the coating increases and then decreases, and the elongation gradually increases. The coating is well combined with the substrate, and the crack origin areas of the tensile specimens are located in the substrate area. Under the process of "heating temperature of 900 ℃+ water quenching to 450 ℃ + natural cooling + tempering temperature of 480 ℃ + natural cooling", the comprehensive performance of IN718 coating is optimal. Its organization is a mixture of a large number of fine dendrites and cellular crystals interspersed with a small number of coarse columnar crystals and dendrites. Its yield strength is 1293±23 MPa, tensile strength is 1407±30 MPa and elongation is 14.4±0.8 %. [Display omitted]