In-situ TiC/Fe0.6MnNi1.4 medium entropy alloy matrix composites with excellent strength-ductility synergy

Abstract TiC/Fe0.6MnNi1.4 medium entropy alloy matrix composites with different volume fractions of TiC particles (i.e., 5, 10 and 15 vol%) were prepared by induction melting method. The experimental results showed that both the base alloy and the composite matrix possess face-centered cubic structure. The in-situ TiC reinforcement phase can significantly increase the mechanical properties of the composites at room temperature. In particular, the hardness, yield strength and ultimate tensile strength of the 10 vol%TiC/Fe0.6MnNi1.4 composite are found respectively to be 528 HV, 345.1 MPa and 716.7 MPa, representing a marked increase by 51.7%, 41.1% and 30.7% in comparison with the Fe0.6MnNi1.4 medium entropy alloy. The ductility of the composite in terms of the elongation to failure is reduced from 65.8% to 36.6% with the increase of the TiC content, which remains attractive for load-bearing structural applications. The strength improvement is underpinned by a combination of the load-bearing effect, Orowan process, dislocation interactions and solid solution effect.