Microstructure and mechanical response of novel Co-free FeNiMnCrAlTi high-entropy alloys

The present study investigates the microstructure and mechanical properties of the Co-free FeNiMnCrAlTi high-entropy alloy (HEA) after casting, homogenizing heat treatment, and hot rolling. The results show that the dendrite regions in the as-cast state were enriched in Cr and Fe and inter-dendritic regions were saturated with Ti and Al. By homogenizing heat treatment, the dendritic solidification structure is eliminated. Furthermore, the microstructure was refined after hot rolling. The EDS and XRD analyses show that despite the matrix and secondary phases' different chemical compositions, their crystal structures are the same. The as-rolled HEA revealed an excellent compromise in mechanical properties: 720 MPa yield strength, 922 MPa ultimate tensile strength, and 30% elongation. A typical ductile failure was observed on the fracture surface of the as-rolled HEA.