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URN etd-0813104-132816 Statistics This thesis had been viewed 2865 times. Download 1204 times. Author Ming Chiang Author's Email Address email@example.com Department Materials Engineering Year 2005 Semester 1 Degree Master Type of Document Master's Thesis Language English Page Count 111 Title Improving the High Temperature Formability of AM60 and AM60-1RE Mg Alloys by Equal Channel Angular Extrusion Keyword rare metal misch metal ECAE AM60 AM60 ECAE misch metal rare metal Abstract Abstract:
Severe deformation processing is an emerging method for refining the grain structure of conventional alloys to micron and submicron levels. As such, this study aims to explore the microstructural evolution and property change in two Mg alloy, namely the AM60 and AM60-1RE, by ECAE processing at 200 ℃ and 270 ℃. The effects of structure evolution and the formation of a dynamic stable grain structure by hot working on the high temperature tensile ductility of the Mg alloys were also examined in this study.
The results showed that an improvement in the higher elevated temperature ductility in AM60 and AM60-1RE alloys was achieved by applying an ECAE processing to the Mg alloys. Grain refinement in the Mg alloys by ECAE at 200 ℃ was found much more effective than at 270 ℃. The fine-grained Mg alloys obtained by ECAE at 200 ℃ exhibit higher high temperature tensile ductility than Mg alloys with a coarser grain structure. A dynamically stable grain structure with a stable grain size was found in the Mg alloys subjected to hot working by ECAE as well as by tensile deformation. The stable grain structure was reached by a dynamic balance between “grain refining” and “grain coarsening” in the process of hot working.
Advisor Committee none - advisor
none - co-chair
none - co-chair
Files Date of Defense 2004-07-31 Date of Submission 2004-08-13