Composition design, microstructure, and mechanical properties of novel Ti–Co–Ni–Zr complex concentrated alloys

The composition design of complex concentrated alloys originates from the composition design of amorphous alloys. To expand the composition design of alloys, herein, the compositions of novel Ti–Co–Ni–Zr complex concentrated alloys were obtained by the proportional mixing of Ti${}_2$Co intermetallics and Ni${}_{64}$Zr${}_{36}$ binary eutectic. The theory and method of this new alloy design are also discussed. The as-cast Ti${}_{28}$Co${}_{14}$Ni${}_{37.12}$Zr${}_{20.88}$, Ti${}_{30}$Co${}_{15}$Ni${}_{35.2}$Zr${}_{19.8}$, and Ti${}_{32}$. Co${}_{16}$Ni${}_{33.3}$Zr${}_{18.7}$ alloys were composed of body-centered cubic TiNi and Ti${}_2$Ni phases. The Ti${}_{28}$Co${}_{14}$Ni${}_{37.12}$Zr${}_{20.88}$ alloy exhibited high yield strength (2 164 MPa) and compressive strength (2 539 MPa) under quasi-static compression at roomtemperature. The high strength of Ti${}_{28}$Co${}_{14}$Ni${}_{37.12}$Zr${}_{20.88}$ alloy is related to the precipitation of Ti${}_2$Ni along the grain boundary and the precipitation in the crystal. This paper validates that using the proportional mixing method of intermetallics and eutectic alloy is an effective method to design complex concentrated alloys with high strength.