Twins and polytypic stacking faults in the ν phase formed in rapidly quenched Mn-Si alloys

Abstract Mn-rich Mn-Si binary alloys containing the ν phase have been prepared by arc-melting and rapid-quenching methods. In comparison, twins and polytypic stacking faults (SFs) are observed in the rapidly quenched ν phase, and the atomic-scale structure properties of twins and SFs have been determined by using aberration-corrected scanning transmission electron microscopy techniques. Both twins and SFs break the crystallographic symmetry of the ν phase, and lead to reconstruction of the subunits of the ν phase at twin boundaries and SFs. On the basis of experimental results, new structural models are proposed to explain the twin and SFs formation in the rapidly quenched ν phase.