Effects of ZrC addition on the microstructure and mechanical properties of Fe-Cr-Al alloys fabricated by spark plasma sintering

ZrC dispersion-strengthened FeCrAl alloys with enhanced high-temperature strength and good ductility were fabricated through spark plasma sintering (SPS) and hot-forging. Nanosized ZrC particles with an average particle size of 56 nm were homogeneously dispersed in the FeCrAl-ZrC alloys. The addition of a small proportion of ZrC nanoparticles effectively refines the grain size and improves the strength and hardness of FeCrAl alloys. However, the ductility of FeCrAl alloys decreases gradually when the ZrC content increases from 0 wt% to 2.0 wt%. The tensile strength of SPSed FeCrAl-1.0 wt% ZrC alloy at 800 °C is 91 MPa, which is about 69% higher than that of pure FeCrAl, while the percentage elongation after fracture of FeCrAl-1.0 wt% ZrC is 15.0%, which is lower than that of FeCrAl (48.2%). To improve the ductility of FeCrAl-ZrC alloys, the SPSed samples were subjected to hot forging at 1000 °C. Through hot-forging, significant enhancement in ductility of FeCrAl-ZrC alloys was achieved without reducing the strength. The mechanical properties and microstructure of FeCrAl-1.0 wt% ZrC are stable after annealing at 1000 °C for 5 h, exhibiting superior thermal stability as compared with FeCrAl.