Grain Coarsening of a Powder Metallurgical High‐Speed Steel After Sliding Wear

Abstract

The microstructure of a powder metallurgical high‐speed steel (PM HSS) after sliding wear is investigated by using electron backscattering diffraction (EBSD) and transmission electron microscope (TEM). Part of martensite blocks become coarsened as the fine blocks can still be seen after sliding wear. The texture, nanolamellar structure, and twin martensite are observed, which suggests that grain rotation and grain boundary migration are driven by plastic deformation and are the main factors for grain growth. However, grain rotation and grain boundary migration are also blocked by carbides and alloy elements segregation, resulting in discontinuous grain growth.

Effect of Spheroidizing Annealing Process on Microstructure and Properties of Quenching and Tempering 60Cr16MoMA Martensitic Stainless Steel

“…[ 38,39 ] However, for HCMSS, carbide fracture and exfoliation are the main mechanisms causing matrix failure. [ 21 ] LAGBs exhibit strong interface adhesive strength, which effectively reduces stress concentration effects and hinders the fracture of carbides, such as peeling off from the matrix. Therefore, as the percentage of LAGBs decreases, there is a noticeable decline in wear resistance.…”

“…[ 20 ] On the contrary, coarse carbide can deteriorate the mechanical properties and corrosion resistance of HCMSS. [ 21–23 ] Roscioli et al showed that carbide peeling off from the blade is the main cause of razor failure such as chipping. [ 24 ] Wang and Li et al reported that the debonding of large‐sized M 23 C 6 carbides from the substrate during the straining process induced microcracks and reduced the toughness of the material.…”