Microstructure evolution of a hypereutectoid pearlite steel under rolling-sliding contact loading

The microstructure evolution on the rolling surface of GCr15 steel subjected to rolling-sliding and pure rolling contact loading was systematically investigated. Experimental results showed that the pearlite structure of the surface layer in the rolling-sliding sample transformed into nanocrystalline α-Fe-C alloy in which cementite underwent severe decomposition while the pearlite lamellae appeared unperturbed in the pure rolling sample. A white etching layer (WEL) was also detected in the surface of the rolling-sliding sample. The WEL formation was found to be due to cyclic shear plastic deformation instead of frictional heating. A surface layer of Fe3O4 was detected in the pure rolling samples. Microhardness depth profiles of the rolling-sliding and pure rolling samples also showed different trends.