Synthesis and Characterization Study of Al10Cr25Co20Ni25Fe20 High-Entropy Alloy Powders through Mechanical Alloying

Abstract

Al₁₀Cr₂₅Co₂₀Ni₂₅Fe₂₀ high-entropy alloys (HEA) with ultrafine grains was synthesized through 30 h of mechanical alloying (MA). The morphological study of prepared high-entropy alloy powders was done by using scanning electron microscope images. Crystallite size and lattice strain of prepared high-entropy alloy were investigated through x-ray diffraction technique. Consolidation and sintering of HEA powders done by two methods such as conventional sintering and spark plasma sintering methods at 1000° and 1200 °C. After 30 h of MA, crystallite size 44 nm and lattice strain 0.182 was obtained. The mechanical properties analysis of high-entropy alloy was done in terms of its density, hardness measurements and compression test. For conventional sintering, the hardness values of 135 ± 6 HV_0.5 for 1000 °C and 186 ± 8 HV_0.5 for 1200 °C were obtained. For spark plasma sintering, the hardness values of 167 ± 5 HV_0.5 for 1000 °C and 212 ± 6 HV_0.5 for 1200 °C was obtained_. Ultimate compressive strength for conventional sintering at 1000 °C and 1200 °C was 246 ± 5 MPa and 305 ± 6 MPa. Ultimate compressive strength of HEA for spark plasma sintered composite at 1000 °C and 1200 °C was 369 ± 5 MPa and 442 ± 5 MPa and the total elongation was 17.7%. BCC and FCC biphase mixture was obtained and confirmed by transmission electron microscopy images and electron backscattered diffraction analysis.