Generation of a Semi solid Magnesium Alloy Feedstock

Jensen, Mark (2002). Generation of a Semi solid Magnesium Alloy Feedstock Honours Thesis, School of Engineering, The University of Queensland.

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Author Jensen, Mark
Thesis Title Generation of a Semi solid Magnesium Alloy Feedstock
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2002
Thesis type Honours Thesis
Supervisor Hao Wang
Total pages 61
Language eng
Subjects 091405 Mining Engineering
Formatted abstract
Semisolid metal forming has many advantages over conventional solid or liquid forming processes. Semisolid casting of magnesium alloys produces castings with less porosity than high pressure die casting, and has the potential to completely eliminate liquid metal handling and consequently improves process safety. Semisolid forging of magnesium alloys has advantages over solid forging as formability is improved. Semisolid forging reduces process steps and the level of capital processing equipment required.

Semisolid metal forming requires a special feedstock with a globular structure. CAST has developed a method to produce a semisolid feedstock for aluminium alloys from low temperature pouring techniques followed by isothermal holding in the semisolid state. This results in a globular structure suitable for semisolid casting. [1] For magnesium alloys there is no commercial method available for the production of a semisolid magnesium alloy feedstock yet. Once it has been developed it is expected that the commercial exploitation of semisolid magnesium processing will be accelerated rapidly.

The aim of this study is to develop a method to produce the semisolid magnesium alloy feedstock. The alloy considered is AZ91, which is the most commonly used alloy of magnesium.

The alloy is cast at different pouring temperatures 675, 700, 725 and 750oC respectively. All materials were isothermally held in the semisolid state. The microstructural evolution was investigated.

The results indicated that after 30min isothermal holding the microstructure becomes globular with an average particle size between 200 and 250 microns. The globular structure is very similar to the aluminium semisolid microstructure, however further work needs to be done to demonstrate the semisolid castability of this material.
Keyword Magnesium Alloy Feedstock

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
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Created: Fri, 28 Nov 2014, 16:41:07 EST by Asma Asrar Qureshi on behalf of Scholarly Communication and Digitisation Service