Flow stress stabilization of Zn-Cu-Mn-Mg alloys using thermomechanical processing

• Published in: Materials characterization 2022-06, Vol.188, p.111928, Article 111928
• Main Authors: Ardakani, Morteza S., Kampe, S.L., Drelich, Jaroslaw W.
• Format: Article
• Language: English
• Subjects: Heat treatment; Microstructure; Room-temperature rolling; Strain rate sensitivity; Strain softening; Zinc alloys
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2022.111928

Zinc-based alloys are potential candidates for bioabsorbable metallic devices due to their application-appropriate corrosion rates and biocompatibility. However, strain softening and rate sensitivity in tensile testing remain as challenges for their use in load bearing applications. In this study, three different Zn-xCu-yMn-0.05Mg (x = 0.5, 1.0 wt%, y = 0.4, 0.6 wt%) alloys were formulated and their microstructure and tensile properties in the room-temperature rolled condition were characterized. Additionally, the effect of short-time annealing at 320 °C on the strain softening and strain rate sensitivity of alloys was studied. The results indicate that dissolution of secondary phases and grain coarsening lead to the suppression of strain softening and strain rate sensitivity. The evolution of microstructure during the room-temperature tensile testing indicates that dynamic recrystallization is responsible for strain softening and can be eliminated by tuning the fraction of secondary phases and underlying grain size. The formulated alloys are not susceptible to natural aging and show good thermal stability during aging up to 200 °C for 60 h due to the pinning effect of MnZn13 precipitates on the grain boundaries. •As-rolled zinc alloys are susceptible to tensile flow softening and are strain-rate sensitive.•Dynamic recrystallization and grain boundary deformation are identified as the source of the mechancial instabilities.•A post-rolled anneal reduces the instabilities by dissolving some of the precipitates and increasing the grain size.•The anneal reduces the driving force for recrystallization by establishing a stable dislocation substructure.•The alloys were not susceptible to natural or artificial aging following the post-roll anneal.