title: Heat treatment mechanism and biodegradable characteristics of ZAX1330 Mg alloy.
abstract: Heat treatments are key processes in the development of biodegradable magnesium implants. The aim of this study is to investigate the factors of microstructures and metallurgical segregation on the functionality of biodegradable magnesium alloy. The solid solution heat treatment and strain induced melting activation heat treatment were employed to alter the microstructures of ZAX1330 alloy in this study. Heat treatments caused a significant change on grain size and distribution of secondary phases. The fine-grained microstructure enhanced the mechanical strength, corrosion resistance and achieved the lowest degradation rate in simulated body fluid solution. In coarse-grained microstructure systems, grain growth followed liquid phase formation. The corrosion rate increased due to a larger cathodic region. The status of micro-alloyed calcium (in solid solution or segregated) influenced the microstructural evolution mechanisms, mechanical strength, and degradation properties. A cytotoxicity test and a live/dead assay showed that ZAX1330 had good cytocompatibility, which varied with heat treatment, and no cell toxicity. The results suggest that heat treatment should be controlled precisely in order to improve the cytocompatibility of magnesium alloys for application in orthopedic implants.
authors.affiliation: Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Da-Jun
authors.initials: DJ
authors.lastname: Lin
authors.affiliation: Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan. Electronic address: fyhung@mail.ncku.edu.tw.
authors.forename: Fei-Yi
authors.initials: FY
authors.lastname: Hung
authors.affiliation: Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Truan-Sheng
authors.initials: TS
authors.lastname: Lui
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Ming-Long
authors.initials: ML
authors.lastname: Yeh
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000737:chemistry* / Q000633:toxicity*; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000633:toxicity; D001826:Body Fluids / Q000737:chemistry; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003343:Corrosion; D006244:Hardness; D006361:Heating; D006801:Humans; D008274:Magnesium / Q000737:chemistry* / Q000633:toxicity*; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D044367:Phase Transition; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D008274:Magnesium
keywords: Biodegradable; Corrosion; Cytocompatibility; Heat treatment; Magnesium alloy; Mechanical properties