Oxidation Resistance of Al_xFeCoNiCrTi Alloys and Its Microstructure and Hardness in Annealing State

The microstructure,phase structure,hardness and oxidation resistance of as-cast and annealed at different temperatures AlxFeCoNiCrTi(x=0.5,1 and 1.5) high-entropy alloys were investigated by using XRD,SEM,DSC and TG.The results show that,with increasing the annealing temperature,Fe2Ti type Laves phase precipitated from Al0.5FeCoNiCrTi and Al1FeCoNiCrTi alloys annealed at 785 ℃.The morphology of fcc and bcc2 phases in the alloys had no transformation,but the grains grew up.The microstructure of Al1.5FeCoNiCrTi alloy was stable,and was as-cast microstructure.The hardness of as-cast and annealed alloys was about 60 HRC and exhibited extreme tempering resistance and possess application value under high temperature condition.The alloys had excellent performance in oxidation resistance,and that of Al0.5FeCoNiCrTi was the best.