The effects of severe plastic deformation on the mechanical and corrosion characteristics of a bioresorbable Mg-ZKQX6000 alloy
In this work, a bioresorbable Mg-ZKQX6000 (Mg–6Zn–0.6Zr–0.4Ag–0.2Ca (wt%)) alloy was severely plastically deformed via equal channel angular pressing (ECAP) according to three unique hybrid routes at low temperatures (200 °C to 125 °C). The roles of ECAP processing on microstructure, and ensuing mechanical properties and corrosion rates, are assessed. Microstructurally, ECAP induces a complex plethora of features, especially variations in grain sizes and precipitates' sizes, distributions, and morphologies for individual cases. Mechanically, ECAP generally refined grain size, resulting in ultra-high strength levels of about 400 MPa in ultimate tensile strength for several cases; however, deformation via ECAP of precipitates induced embrittlement and low elongation to failure levels. Corrosion testing, conducted in simulated bodily fluid at bodily pH levels to mimic conditions in the human body, revealed consistent corrosion rates across several techniques (mass loss, hydrogen evolution, and electrochemical impedance spectroscopy (EIS)), showing that severe plastic deformation deteriorates corrosion resistance for this material. In-situ corrosion monitoring explained that corrosion accelerated after ECAP due to the creation of heterogeneous, anodic shear zones, which exhibited dense regions of refined grains and fine precipitates. Suggestions for future design and thermomechanical processing of Mg alloys for bioresorbable orthopedic implants are provided.
Other Information
Published in: Materials Science and Engineering: C
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.msec.2020.111130
Funding
Open Access funding provided by the Qatar National Library
History
Language
- English
Publisher
ElsevierPublication Year
- 2020
License statement
This Item is licensed under the Creative Commons Attribution 4.0 International LicenseInstitution affiliated with
- Texas A&M University at Qatar