Temperature effects on microstructure and mechanical properties of sintered high-entropy equiatomic Ti20V20Al20Fe20Cr20 alloy for aero-gear application

Abstract

This work presented an upgraded high-entropy alloy by the addition of chromium to the conventional Ti-10V-2Fe-3Al alloy to fabricate equiatomic Ti20V20Al20Fe20Cr20 high-entropy alloy via spark plasma sintering powder processing at different temperature of 700 °C, 800 °C, 900 °C, 1000 °C, and 1100 °C respectively under a constant heating rate of 100 °C /min, the pressure of 40 MPa, and holding time of 5 min. The microstructure and phase transformation of the sintered alloyed were studied with a scanning electron microscope equipped with energy dispersive spectroscopy. The constituent phases present in the sintered high-entropy alloy were analyzed by X-ray diffraction and were found to show increased development of body-centered cubic solid solution alloys across the temperature gradients. The mechanical properties over a temperature range of 700 ≤ T °C ≤ 1100 generally show an increase in hardness from 3363 to 8480 MPa, tensile strength from 1097.17 to 2766.58 MPa, and yield strength from793.61 to 2001.13 MPa respectively. The SEM-EDS of Ti20V20Al20Fe20Cr20 equiatomic high-entropy alloys show the existence of a nano-net-like spinodal structure at the optimum temperature of 1100 °C, which are rich in body centered cubic structure. At this elevated temperature, the presence of strong body-centered cubic–forming elements such as Cr, Fe, and Al was established from the corresponding EDS. Ti20V20Al20Fe20Cr20 high-entropy equiatomic alloy has been successfully fabricated by spark plasma sintering. The effects of temperature on microstructural and mechanical properties of the sintered Ti20V20Al20Fe20Cr20 alloy demonstrated a general improvement of the alloys at the elevated region.