Effect of carbon on tensile properties and wear behavior of P/M FeAl alloy

Powder metallurgy (P/M) Fe-40Al and Fe-40Al-3.5C alloys (all compositions are in atomic percent) were produced by hot extrusion of gas-atomized powders to study the effect of carbon addition on microstructure, tensile properties and wear behavior of FeAl. Precipitation of soft graphite phase was observed in the carbon-added alloy. Tensile tests showed that the addition of carbon slightly increased yield strength at temperatures below 800 K, but significantly improved ductility, especially at elevated temperatures. The improvement in ductility was considered to be mainly due to the grain refinement in the carbon-added alloy. The wear behavior was studied by ball-on-disk sliding wear test. The carbon addition greatly improved the wear resistance of the Fe-40Al alloy at room temperature, but the effect was not significant at elevated temperatures. Examination of the worn surface and wear debris revealed that the improved wear resistance of the carbon-added alloy at room temperature was associated with the lubrication effect of graphite.