Improving corrosion resistance of spark plasma sintering-produced AlCoCrFeNi2.1 high entropy alloy via in-situ process pressure and temperature control

The ability to control phases in eutectic high-entropy alloys (EHEAs) remains a formidable challenge. This study illustrates a simple approach that applies various sintering temperature and pressure to achieve precise control of phase transformation in AlCoCrFeNi2.1 EHEA, particularly to further enhance its corrosion resistance. The result display that at high sintering pressure, pore density in sintered material could be reduced significantly, and at high sintering temperature, BCC phase is seen a notable growth, which both determine the corrosion performance of studied alloy. Moreover, it is found that large BCC phase size could reduce micro-galvanic effect between FCC and BCC and then improve corrosion resistance. This work may provide a technological implication in the EHEA design for anti-corrosion.