Mechanical Properties and Microstructure Evolution of Cryorolled AlCoCrFeNi-Reinforced Aluminum Matrix Composites Tensile Tested at Room and Cryogenic Temperatures

KG Luo and G Lei and SL Liu and CR Kong and HL Yu, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 54, 2292-2310 (2023).

DOI: 10.1007/s11661-023-07012-0

The AlCoCrFeNi high-entropy alloy particles (HEAp)-reinforced aluminum matrix composites (AMCs) were fabricated by stir casting and subsequent cryorolling. The tensile mechanical properties of the HEAp/AMCs were investigated at room temperature (298 K) and cryogenic temperature (173 K). The microstructures of the HEAp/AMCs were studied using scanning electron microscopy (SEM), electron backscatter diffraction, and transmission electron microscopy (TEM). The tensile tested results show that both the ultimate tensile strength and elongation of HEAp/AMCs sheets at cryogenic temperature are higher than those at room temperature. The ultimate tensile strength of 3 wt pct HEAp/AMCs is increased from 204 MPa (room temperature) to 251 MPa (cryogenic temperature). The improvement in strengths of the HEAp/AMCs at cryogenic temperature is due to the coefficient of thermal expansion mismatch reinforcement and the dislocation reinforcement. The HEAp/AMCs have a higher elongation in the cryogenic environment, in which the particles have a higher length-diameter ratio along the tensile direction. The molecular dynamics simulation of void nucleation in aluminum alloy deformed at 298 K and 173 K shows that the void nucleation threshold is higher and the nucleation rate is slower at cryogenic temperature, which contribute to the higher elongation of the HEAp/AMCs.

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