Evolution of shear amorphization in superhard cubic silicon carbide

Abstract

Shear amorphization induced by high stress in cubic silicon carbide (β-SiC) has not yet been experimentally observed till-to-date. In this letter, we report the detailed evolution of stress-induced amorphization in superhard β-SiC using transmission electron microscopy (TEM) and molecular dynamics (MD) simulations. From experimental observations using TEM, shearing by stacking faults along (111) crystallographic plane triggers the onset of amorphization. Further, an increase in the stress results in highly localized strains within the amorphous band led by the coalescence of vicinity dislocations. Based on the MD simulations, it has been verified that the existence of stacking faults decreases the amount of shear stress and shear strain necessary to trigger amorphization compared to the pristine β-SiC, which is in line with experimental observations. This study underscores a detailed understanding of the amorphization process in superhard materials through which stress is alleviated in high-stress environments.