title: Corrosion fatigue behaviors of two biomedical Mg alloys - AZ91D and WE43 - In simulated body fluid.
abstract: Magnesium alloys have been recently developed as biodegradable implant materials, yet there has been no study concerning their corrosion fatigue properties under cyclic loading. In this study the die-cast AZ91D (A for aluminum 9%, Z for zinc 1% and D for a fourth phase) and extruded WE43 (W for yttrium 4%, E for rare earth mischmetal 3%) alloys were chosen to evaluate their fatigue and corrosion fatigue behaviors in simulated body fluid (SBF). The die-cast AZ91D alloy indicated a fatigue limit of 50MPa at 10⁷ cycles in air compared to 20MPa at 10⁶ cycles tested in SBF at 37°C. A fatigue limit of 110MPa at 10⁷ cycles in air was observed for extruded WE43 alloy compared to 40MPa at 10⁷ cycles tested in SBF at 37°C. The fatigue cracks initiated from the micropores when tested in air and from corrosion pits when tested in SBF, respectively. The overload zone of the extruded WE43 alloy exhibited a ductile fracture mode with deep dimples, in comparison to a brittle fracture mode for the die-cast AZ91D. The corrosion rate of the two experimental alloys increased under cyclic loading compared to that in the static immersion test.
authors.affiliation: State Key Laboratory for Turbulence and Complex System, College of Engineering, Peking University, Beijing 100871, China.
authors.forename: X N
authors.initials: XN
authors.lastname: Gu
authors.forename: W R
authors.initials: WR
authors.lastname: Zhou
authors.forename: Y F
authors.initials: YF
authors.lastname: Zheng
authors.forename: Y
authors.initials: Y
authors.lastname: Cheng
authors.forename: S C
authors.initials: SC
authors.lastname: Wei
authors.forename: S P
authors.initials: SP
authors.lastname: Zhong
authors.forename: T F
authors.initials: TF
authors.lastname: Xi
authors.forename: L J
authors.initials: LJ
authors.lastname: Chen
mesh_terms: D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D001826:Body Fluids / Q000737:chemistry*; D003343:Corrosion; D004573:Electrolytes / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D004573:Electrolytes; D008274:Magnesium