Deformation mechanism of L12-type multicomponent intermetallics: The generalized stacking fault energy and chemical bonds
Xinghua Zhu, Yutian He, Qingguo Feng, Ning Wang, Changchun Ge, Yi Xu
Abstract
Multicomponent L12-type material has been shown to be one of the important precipitates used to enhance the properties of high entropy alloys. Its controllability is elusive due to the complexity of the content, which has led to slow progress in the study of their electronic structure. Here, we investigated the deformation mechanism of (Co, Fe, Ni)3Ti-type multicomponent intermetallics using first principles. Thermodynamic parameters, energy and electronic structure suggest that Fe favors a lower γSPF while Ni favors a higher γSPF, which is caused by the difference in the chemical bonding they contribute. The stable outermost electron orbital achieved by Ni-Ti contributes to the good mechanical properties, while the excess lone pair electrons provided by Fe would make the contribution of metallic bonding more significant. Adjustment of the intermetallics-favoring/alloys-favoring element ratio is an effective method to overcome the strength-ductility trade-off. This work provides electronic-level understanding and practical insights to better design and utilize the multicomponent intermetallics enhanced high entropy alloys.