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Test specimens of magnesium alloys with two, five, six and nine weight percent aluminum were produced by high pressure die casting. The results of room temperature mechanical tests were combined with data from prior investigations to provide property trends as a function of aluminum content. The strength and ductility properties of these alloys generally show opposite dependencies with a change in the aluminum content. Design engineers must therefore make material selection decisions based upon the best balance of properties available for the intended application.

Three series of die cast corrosion test plates representing two alloy compositions and two processing methods were exposed to salt spray corrosion for various times up to 810 hours. In addition to the measurement of weight loss due to exposure, the appearance of the corroded plate surfaces was studied both macroscopically and microscopically. Numerous plates were also chemically analyzed to assist in documentation of the corrosion effects. The most significant observation to emerge from the subject experiments was that the runner, gate and die designs established a metal flow pattern which was intimately connected with aspects of corrosion. For the test plate castings considered herein, regions of preferential pitting and boundaries separating levels of more general corrosion were both associated with reproducible metal flow patterns.