Microstructure and Properties of FeCoNiTix Medium-Entropy Alloy and Its Application in Cemented Carbides
FeCoNi medium-entropy alloy exhibits excellent properties compared with traditional alloys,but its room temperature strength is not high,which limits its application.The blocks of FeCoNiTix(x=0,0.25,0.50,0.75,1)medium-entropy alloy were prepared by mechanical alloying and spark plasma sinte-ring.The effects of mechanical alloying sequence of each element and Ti content on the microstructure and properties of FeCoNiTix medium-entropy alloy were emphasized.Additionally,preliminary exploration was conducted on the application of FeCoNiTix medium-entropy alloy as binder in WC-based cemented car-bides.The results show that the FeCoNi matrix phase is FCC phase during mechanical alloying,and the ad-dition of Ti element results in the formation of Laves phase and titanium oxide phase.Therefore,the phase of FeCoNiTix medium-entropy alloy consists of FCC phase,Laves phase and titanium oxide phase.With the increase of Ti content,the density,hardness and strength of FeCoNiTix alloy increase,while the plasticity increases at first and then decreases.The FeCoNiTi0.50 medium-entropy alloy exhibits good mechanical properties,and its microhardness,yield strength,compressive strength and compressive strain are 531 HV,1 987.57 GPa,2 114.85 GPa and 20.5％,respectively.The addition of a small amount of Ti element can enhance the corrosion resistance of FeCoNi alloy.FeCoNiTix binder can exist stably in WC-based cemented carbides,inhibiting the formation of decarburization phase in the sintering process of WC.WC-FeCoNiTi0.5o cemented carbide exhibits good mechanical properties,and its microhardness and fracture toughness are 1 834 HV and 15.12 MPa·m1/2,respectively.
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