Microstructural Evolution of Ti–Al–Ni (Cr,Co,Fe)-Based High-Entropy Alloys Processed Through Mechanical Alloying

TiAlNiCr, TiAlNiCrCo, TiAlNiCrFe, TiAlNiCrCoFe, TiAlNiCo, TiAlNiFe and TiAlNiCoFe high-entropy alloys were processed through mechanical alloying followed by spark plasma sintering (SPS). All the alloys develop a BCC (Cr-/Cr–Fe-rich) structure after mechanical alloying. Sintering at high temperature promotes the formation of one more BCC phase which is of NiAl type. Phase evolution after mechanical alloying and SPS was studied using X-ray diffraction. Composition of the phases was analysed using energy-dispersive spectroscopy, and microstructural characterisation was done using back-scattered electron images. Characterisation studies done on the alloys confirm the presence of BCC phases. Alloys without Cr develop a single BCC peak after SPS compared to alloys with Cr.