FeZn13 intermetallic compound in biodegradable Zn-Fe alloy: Twinning and its shape effect

摘要

FeZn13 intermetallic compound is the main second phase in recently developed biodegradable Fe-containing Zn alloys, including Zn-Fe, Zn-Mn-Fe and Zn-Cu-Fe alloys. However, knowledge of twinning in FeZn13 is very limited. In this paper, full elements of {110} twinning in FeZn13 are solved, including the twinning and the reciprocal twinning planes, the twinning and the reciprocal twinning directions, the shear plane and the shear magnitude. Only two of the former four elements are rational so that {110} twin belongs to Type I twin. The twinning system can be described as {110} < - 1, 1, - 2.81 >. There exist two possible twin variants with a misorientation of < 001 > 70.94 degrees with respect to the parent crystal. An outer twin leads to a mirror symmetrical shape of FeZn13 particles, while an inner twin does not change their rhombus-like shape with an acute angle of 70.94 degrees, enclosed by facets parallel to {110}.