Microstructure Refinement and Enhanced Mechanical Properties In Rapid-Quenched Mncrfeconi High-Entropy Alloy

Abstract

High-entropy alloys (HEAs) have gained significant attention in recent years, due to their unique properties derived from the combination of multiple elements in equimolar or near-equimolar ratios. The mechanical properties of HEAs are strongly influenced by their microstructural characteristics. In this study, MnCrFeCoNi HEA ribbons were produced using a technique called melt spinning, where the wheel speed was adjusted to control the undercooling levels. The rapid solidification process under the specific undercooling conditions resulted in refined grain sizes to micrometers in the ribbons. One notable feature was the presence of twin boundaries, which especially accounted for approximately 7.36% of the microstructure for the ribbons produced at a wheel speed of 10 m/s. This refined grain size and the occurrence of twin boundaries contributed to an improved hardness of around 2.5 GPa. However, when the thickness of the ribbons was reduced to the micrometre scale (dozens of micrometre), the ultimate tensile strength showed a decrease with decreasing grain size (GS). This behavior could be attributed to either the thickness effect. Overall, this study provides a new approach for tailoring the microstructures and mechanical properties of HEAs using the melt spinning technique. The use of ribbon-form HEAs present a novel form factor that could potentially broaden the scope of applications for these materials.

Keywords: Melt spinning, Grain refinement, High-entropy alloys, mechanical properties