The influence of severe plastic deformation on mechanical properties of pure zinc

Biodegradable materials, which have the ability to resorb in the body, are new and promising materials for medical implants. Currently, scientists carry out the investigations according to three directions: Mg, Fe, and Zn alloys. Zinc-based alloys and zinc have good solubility in the body, which meets the clinical requirements of implants. However, pure zinc has low mechanical properties, including hardness and tensile strength. Therefore, at present, the world scientific community is seeking ways to improve the properties of pure zinc by alloying. Another known approach is the ultrafine-grained (UFG) structure formation by the severe plastic deformation (SPD) methods, which are based on the large plastic deformations under high pressure and relatively low homologous temperatures. In this work, the authors studied the influence of high pressure torsion of pure zinc with various numbers of revolutions. The paper presents calculations of shear deformation after SPD. The authors investigated the dependence of mechanical properties and microstructure on the deformation degree. Tension tests at room temperature were carried out, and microhardness was measured. The authors studied the structure using scanning electron microscopy and optics. The study identified that the use of high pressure torsion leads to an increase in the tensile strength of pure zinc up to 140 MPa and ductility up to 40 % resulting from dynamic recrystallization.