Stress corrosion cracking and corrosion fatigue characterisation of MgZn1Ca0.3 (ZX10) in a simulated physiological environment

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• 作者：Sajjad Jafari^a ; ^{jafarisajjad1@gmail.com} ; R.K. Singh Raman^a ; ^b ; Chris H.J. Davies^a ; Joelle Hofstetter^c ; Peter J. Uggowitzer^c ; Jö ; rg F. Lö ; ffler^c
• 关键词：Biodegradable implants ; Magnesium alloys ; Stress corrosion cracking ; Corrosion fatigue ; Twinning
• 刊名：Journal of the Mechanical Behavior of Biomedical Materials
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：65
• 期：Complete
• 页码：634-643
• 全文大小：3703 K
• 卷排序：65

文摘

Magnesium (Mg) alloys have attracted great attention as potential materials for biodegradable implants. It is essential that an implant material possesses adequate resistance to cracking/fracture under the simultaneous actions of corrosion and mechanical stresses, i.e., stress corrosion cracking (SCC) and/or corrosion fatigue (CF). This study investigates the deformation behaviour of a newly developed high-strength low-alloy Mg alloy, MgZn1Ca0.3 (ZX10), processed at two different extrusion temperatures of 325 and 400 °C (named E325 and E400, respectively), under slow strain tensile and cyclic tension-compression loadings in air and modified simulated body fluid (m-SBF). Extrusion resulted in a bimodal grain size distribution with recrystallised grain sizes of 1.2 μm ± 0.8 μm and 7 ± 5 μm for E325 and E400, respectively. E325 possessed superior tensile and fatigue properties to E400 when tested in air. This is mainly attributed to a grain-boundary strengthening mechanism. However, both E325 and E400 were found to be susceptible to SCC at a strain rate of 3.1×10−7 s−1 in m-SBF. Moreover, both E325 and E400 showed similar fatigue strength when tested in m-SBF. This is explained on the basis of crack initiation from localised corrosion following tests in m-SBF.