Hot tensile properties of CoCrFeMnNi(NbC) compositionally complex alloys

An investigation was performed on tensile deformation behaviour and its relation with the microstructure of CoCrFeMnNi and CoCrFeMnNi(NbC) compositionally complex alloys at room temperature, 500, 600 and 700 °C. Microstructural characterisations and fractography were performed using optical microscopy, scanning electron microscopy and wavelength dispersive spectroscopy, X-ray diffraction, whereas hardness was obtained by Vickers hardness testing. The results showed that Nb–C addition can considerably increase the strength of CoCrFeMnNi alloy at room and high temperatures, while it can reduce the elongation up to about 50%. Microscopy observations demonstrated that the higher strength of CoCrFeMnNi(NbC) compared to CoCrFeMnNi was primarily related to the effect of carbide precipitates. Moreover, a larger grain size and carbide precipitates were responsible for the lower elongation of CoCrFeMnNi(NbC).