Effect of Cooling Rate on the Phase Formation of AlCoCrFeNi High-Entropy Alloy
P Sreeramagiri and A Roy and G Balasubramanian, JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION, 42, 772-780 (2021).
High-entropy alloys have received significant attention because of remarkable structural properties exhibited by certain alloy compositions. However, these properties are strongly correlated to the crystallographic phase transformations that are endured during the synthesis of these alloys. Using molecular dynamics simulations, we examine how the cooling rates exerted on the alloy melt during synthesis impact the crystallization (and glass formation) of equiatomic AlCoCrFeNi high-entropy alloy. An increased cooling rate contributes to severe undercooling of the alloy, reducing the crystallization temperatures and promotes phase transformations. We predict a critical cooling rate of 2.5 x 10(10) K/s beyond which the alloy tends to solidify into an amorphous phase. Our results reveal that higher cooling rates exert severe lattice distortion and significantly enhance the structural properties due to increase in dislocation density and deformation by twinning.
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