Production and Die Casting of Semi-Solid Magnesium Alloy AZ91D Materials Technology Laboratory/CANMET, Natural Resources Canada

Format:

Book

Conference/Event

Author/Creator:

Shehata, M. T., author.

Conference Name:

SAE 2002 World Congress & Exhibition (2002-03-04 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2002

Summary:

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

Notes:

Vendor supplied data

Publisher Number:

2002-01-0082

Access Restriction:

Restricted for use by site license