Investigating the stress corrosion cracking of a biodegradable Zn-0.8 wt%Li alloy in simulated body fluid

Abstract

Stress corrosion cracking (SCC) may lead to brittle, unexpected failure of medical devices. However, available researches are limited to Mg-based biodegradable metals (BM) and pure Zn. The stress corrosion behaviors of newly-developed Zn alloys remain unclear. In the present work, we conducted slow strain rate testing (SSRT) and constant-load immersion test on a promising Zn-0.8 wt%Li alloy in order to investigate its SCC susceptibility and examine its feasibility as BM with pure Zn as control group. We observed that Zn-0.8 wt%Li alloy exhibited low SCC susceptibility. This was attributed to variations in microstructure and deformation mechanism after alloying with Li. In addition, both pure Zn and Zn-0.8 wt%Li alloy did not fracture over a period of 28 days during constant-load immersion test. The magnitude of applied stress was close to physiological condition and thus, we proved the feasibility of both materials as BM.

Keywords

• Biodegradable metals
• Zn-0.8 wt%Li alloy
• Stress corrosion
• Slow strain rate testing
• Constant-load immersion test