EFFECT OF SEVERE PLASTIC DEFORMATION BY THE ECAP-CONFORM METHOD ON THE STRUCTURE AND MECHANICAL PROPERTIES OF BIORESORBABLE ZINC ALLOY ZN-0.8LI

Abstract

At present, one of the relevant and actively developing directions of medical materials science is the creation of bioresorbable implants used for the restoration of bone defects. This requires materials with sufficiently high mechanical properties and a controlled corrosion rate. An alternative to the widely known magnesium alloys for bioresorbable implants are zinc alloys. Zn alloys exhibit optimal corrosion resistance for use as a material for the manufacture of bioresorbable implants. However, zinc alloys are less studied and have low mechanical properties. In the present work, studies of the influence of severe plastic deformation by the ECAP-Conform method on the structure and mechanical properties of zinc alloy Zn-0.8Li were carried out. As a result of deformation, the structural constituents were refined. The structure in the longitudinal cross-section of the ECAP-Conform rod differs noticeably from the structure in the transverse cross-section, which determines the strong anisotropy of mechanical properties. In the transverse cross-section, the structure of the LiZn₄ phase matrix with inclusions of Zn-LiZn₄ eutectic globules is observed, whereas a banded structure is observed in the longitudinal cross-section. As a result, the rod in the longitudinal cross-section demonstrates record values of strength characteristics for the alloy (yield strength and ultimate tensile strength amounted to 580 and 520 MPa, respectively) and high plasticity of 43%, while samples in the transverse cross-section failed in a brittle manner.