Influence of the Degree of HPT Deformation on the Microstructural Characteristics and Mechanical Properties of the Zn–4Ag–1Cu Alloy

Abstract

This study investigated the microstructure and mechanical properties of a Zn–4Ag–1Cu (wt %) alloy processed by high-pressure torsion (HPT) at room temperature through 1 to 10 turns. Microstructural analysis reveals that HPT processing results in the formation of a homogeneous ultrafine-grained (UFG) structure in the alloy samples, with a grain size ranging from 250 to 600 nm, containing nanoscale particles of secondary phases. In the early stages of deformation, after HPT with 1 to 10 turns, a significant increase in strength properties is observed in the UFG samples compared to the initial state. The yield stress and ultimate tensile strength reach 165 and 236 MPa, respectively. An increase in the number of HPT turns from 1 to 10 is accompanied by a decrease in strength and a notable increase in the plasticity of the samples. The elongation to failure increases by an order of magnitude, from 13 to 112 and 250%. Experimental data confirm the manifestation of grain boundary sliding and dynamic recrystallization effects, leading to a significant increase in the plasticity of the UFG alloy at room temperature. This study demonstrates the high efficiency of using the HPT method to form a UFG structure in the Zn–4% Ag–1% Cu alloy, which provides a combination of properties attractive for bioresorbable implants and stents used in medicine.