Processing and microstructure-property relations of high-strength low-alloy (HSLA) Mg-Zn-Ca alloys

Deformation dilatometry and semi-industrial extrusion were used to investigate the effect of different thermomechanical processing routes on the microstructure and mechanical properties of the low-alloy Mg alloys ZX10 (Mg-1Zn-0.3Ca) and ZX00 (Mg-0.5Zn-0.15Ca). It is shown that the deliberately adjusted formation of intermetallic particles beneficially influences dynamic recrystallization and grain growth, with the result of a fine-grained microstructure (grain size < 2 mu m). The presence of unrecrystallized regions with its unfavorable influence on ductility and mechanical anisotropy can be controlled by the selection of an indirect extrusion mode. Meta-dynamic recrystallization generates almost fully recrystallized microstructures and hence the desired properties, which are characterized by high strength (yield strength approximate to 240 MPa), simultaneously high ductility (elongation to fracture approximate to 30%), and low structural and mechanical anisotropy. These properties are of great interest for light-weight applications and for deployment as biodegradable implants in medical technology. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.