Australian alloy

A new Australian magnesium alloy featuring mirror finish, strength and lightness is exciting interest among manufacturers and designers around the world.

AM-lite is a magnesium high-pressure die casting alloy developed by an international research team led by Australian firm Advanced Magnesium Technologies (AMT) and the CAST Cooperative Research Centre (CAST CRC).

According to the centre, AM-lite is the first magnesium alloy that can be readily electroplated, and is stronger and more suitable for decorative applications than most of its competitors, including zinc, plastics, aluminium and existing magnesium alloys.

The development of AM-lite began with a serendipitous discovery. “We were actually trying to develop a low-cost magnesium alloy that resisted deformation for use in engine blocks,” explains CAST CRC chief executive Professor David StJohn. “This particular one didn’t work out for that purpose, but we noticed that castings of the alloy gave a beautiful surface finish.”

The discovery was made by researcher Dr. Trevor Abbott, of Monash University, who now heads the AMT research team which is helping commercialise the new technology.

There was also drama when AM-lite underwent initial casting trials in Europe. The first two trials showed the alloy was promising but some essential properties were not up to market requirements. But the team solved the problem and the third trial was a triumph, Prof. StJohn says.

Mr Hartnell says that the AM-lite technology will be produced under licence by partner companies in China, Japan, Europe and Canada and marketed worldwide under the AMT brand.

While retaining advantages common to magnesium alloys AM-lite diecastings have superior surface quality and definition, and thinner sections can be cast than for other magnesium alloys. It is particularly suited for decorative electroplating, powder coating and electrophoretic painting.

Compared with zinc, the alloy is 70% less dense, produces three times more parts per unit weight of metal and diecast parts cost 10-30% less. Compared with standard magnesium alloys it is cheaper, easier to cast and carries a much better finish, including the ability to be electroplated.

Compared to plastics, AM-lite is stronger and stiffer, conducts heat and provides electromagnetic shielding.