Effect of Aging Heat Treatment on Microstructure and Properties of Laser-deposited CoCrW Wear-resistant Layer on Surfure of K417G Alloy

A CoCrW alloy wear-resistant layer was prepared on the surface of K417G superalloy by laser melting deposition technology.The effects of aging heat treatment temperatures (760 ℃, 860 ℃, 960 ℃) on the microstructure, phase composition, microhardness and friction and wear properties of the CoCrW alloy wear-resistant layer were investigated. The results show that the microstructure of the wear-resistant layer consists of columnar grains and equiaxial grains at different aging temperatures, and the main phases are γ-Co, M₇C₃ and M₂₃C₆. With the increase of aging heat treatment temperature, the primary eutectic carbide M₇C₃ in the microstructure is decomposed gradually and reacts with the Cr element, which leads to the secondary precipitation of a large number of fine carbides M₂₃C₆ around M₇C₃ and achieving an obvious grain refinement strengthening effect. The microhardness and wear resistance of the wear-resistant layer increase gradually with the elevation of aging heat treatment temperature, and the hardness and wear resistance of the wear-resistant layer are optimal at 960 ℃. The average microhardness reaches 703 HV0.3, with a friction coefficient of 0.26 and a wear mass loss of only 0.65 mg