Production and Die Casting of Semi-Solid Magnesium Alloy AZ91D 2002-01-0082
Semi-solid forming is a relatively new process whereby an alloy with thixotropic characteristics at a temperature between solidus and liquidus is cast into a component in a mould. This technology is based on research originally carried out at MIT in the 1970s on rheological properties of semi-solid metals subjected to mechanical stirring. By not starting with a super-heated melt as in conventional liquid pressure die casting, semi-solid processing offers distinct advantages such as low cycle time, less porosity because of non-turbulent flow, improved die life and significantly better mechanical properties.
The success or failure in the production of a component largely depends on the temperature uniformity and microstructural homogeneity of the semi-solid thixotropic feedstock prior to injection. This paper describes results of work related to the preparation of AZ91D feedstock by electro-magnetic stirring combined with superheat reduction, reheating of this material to the thixotropic state by induction and semi-solid die casting a number of complex box-like components. The reheating was carried out in a single induction coil programmed to provide variable power input such that a low temperature gradient and a minimal liquid metal segregation in the billet feedstock were realized. The microstructure was monitored throughout the processing to achieve the desired semi-solid microstructure for successful die casting. The optimal casting parameters (metal temperature, ram velocity and metal pressure) for die casting the box-like components are given.
Citation: Shehata, M., Kao, V., Essadiqi, E., Loong, C. et al., "Production and Die Casting of Semi-Solid Magnesium Alloy AZ91D," SAE Technical Paper 2002-01-0082, 2002, https://doi.org/10.4271/2002-01-0082. Download Citation
Author(s):
M. T. Shehata, V. Kao, E. Essadiqi, C. A. Loong, C-Q Zheng
Affiliated:
Materials Technology Laboratory/CANMET, Natural Resources Canada, Industrial Materials Institute, National Research Council Canada
Pages: 8
Event:
SAE 2002 World Congress & Exhibition
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
Lightweight MagnesiumTechnology 2001- 2005-PT-131, Light Metals for the Automotive Industry-SP-1683, SAE 2002 Transactions Journal of Materials & Manufacturing-V111-5
Related Topics:
Casting
Magnesium alloys
Forming
Production
Metals
Alloys
Starters and starting
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