A new type of high entropy alloy composite Fe18Ni23Co25Cr21Mo8WNb3C2 prepared by mechanical alloying and hot pressing sintering

In this work, a new type of high entropy alloy (HEA) composite Fe18Ni23Co25Cr21Mo8WNb3C2 was prepared by mechanical alloying (MA) and hot pressing sintering (HPS). Phase transitions, microstructure characteristics, and tensile properties of samples were analyzed. During the MA process, a powder mixture of Cr-Mo was milled to synthesize the amorphous alloy powder Cr(Mo)a. Then, the mixture of amorphous alloy powder Cr(Mo)a and other elemental powders (Fe, Ni, Co, W, Nb, and C) was milled to obtain the HEA powder. This HEA powder is composed of single-phase austenite (γ). Finally, the HEA powder was consolidated using HPS. The sintered HEA composite contains the matrix phase austenite A and second-phase M6C carbide. The precipitation reaction that occurs during the sintering process can be summarized as: γ→A + M6C. Tensile properties of the sample sintered at 1050 °C were tested. At room temperature, ultimate tensile strength and elongation are ~ 1452 MPa and ~ 3.9%, respectively; at 650 °C, ultimate tensile strength and elongation are ~ 795 MPa and ~ 13.3%, respectively.