MD study on topologically close-packed and configuration entropy of Mg40Al60 metallic glasses under rapid solidification

Abstract

Herein, the effects of cooling rate during rapid solidification of Mg40Al60 metallic glasses are studied using the molecular dynamics (MD) simulation. The system energy, pair distribution function (PDF), local structures, configuration entropy, and three-dimensional visualization are used to systematically analyze the evolution of microstructure with temperature. Results indicate that the lower the cooling rate, the lower the average atomic energy. With the decrease of cooling rate, increases the height difference between two splitting subpeaks of the second peak on PDF curves; while decreases the onset temperature of glass transition. The effect of the cooling rate on the topologically close-packed (TCP) clusters is similar to the local five-fold structures of S555: the lower the cooling rate, the more the amount of TCP clusters, and the lower the configuration entropy. In addition, most TCP clusters are centered the smaller Al atoms.