Comparison of the damage and microstructure evolution of eutectoid and hypereutectoid rail steels under a rolling-sliding contact

The wear and rolling contact fatigue (RCF) performance of eutectoid hypereutectoid rail steels were studied. Subsequently, the microstructure evolutions subsurface materials these two after testing comparatively investigated. results indicated that, compared with rail, had lower loss, but longer RCF crack lengths. After rolling-sliding testing, original equiaxed undeformed coarse grains rails in matrix transformed into nano-grains rich high angle grain boundaries (HAGBs). evolution under could be explained by mechanisms. Firstly, initial deformation breaking lamellar structure pearlite occurred through movement dislocations. Secondly, formation nanostructure happened continuous dynamic recrystallization (cDRX). Compared finer interlamellar spacing higher contents low (LAGBs) matrix. more severe LAGBs-to-HAGBs transitions a cDRX process than which might reason for lengths it exhibited.