Microstructure and Properties of WCP Reinforced Ferrous Gradient Composites

Two kinds of thick-walled rings, consisted of WCP/Fe-C gradient composites layers containing about 54 and 70 vol.% of WCP and Fe-C alloy core, were cast by centrifugal casting method. The microstructure, mechanical properties and wear resistance of the gradient composites were investigated. Meanwhile the results were compared with those made of the high speed steel. It was found that WCP in the two kind of gradient composites layers were even well distributed, WCP/Fe-C composites layer of 23-28mm was obtained, the transition layer between the composites layer and matrix alloy core was perfect. The tensile strengths of the two gradient composites layers achieved 345MPa, 460MPa and the impact toughness were 4.6J/cm2, 6.2J/cm2 respectively. Moreover the hardness of the composites layers attained HRA81 and HRA 78. The result of the comparison among the gradient composites layers and that made of the high speed steel showed that the wear resistance of the gradient composites layers containing about 50 and 70 vol.% of WCP was more than 20 times higher than that of the high speed steel under loads of 100N and 200N and sliding velocity of 60 m/s. Finally, the wear-mechanism was discussed.