Sumitomo Electric Develops Magnesium Alloy for Die Casting with Superior Heat Resistance

Sumitomo Electric Industries, Ltd. has developed jointly with the University of Toyama a high heat-resistant magnesium alloy for die casting*¹ applications.

The automotive industry is presently required to conserve the environment by reducing CO₂ emissions of vehicles. A promising way of meeting the above requirement is to improve the fuel efficiency of vehicles by reducing their weight. In particular, engine component materials, which are mainly aluminum alloys, are required to be replaced with lighter magnesium alloys.

Due to their low castability and heat resistance, high component production cost, and low recyclability, conventional magnesium alloys cannot be used as substitutes for aluminum alloys. Sumitomo Electric conducted joint research with Prof. Seiji Saikawa of the faculty of engineering, the University of Toyama, and succeeded in developing a new heat-resistant magnesium alloy free of the above shortcomings.

The newly developed magnesium alloy has the following outstanding features:

1. Superior in heat resistance (compressive creep characteristics*³ and tensile strength at 150-200℃)
2. Superior in die castability
3. Little change in composition by remelting and casting, which makes the alloy recyclable
4. Non-use of costly rare-earth element

Sumitomo Electric will establish a new alloy ingot production system to introduce alloy products into the market. In parallel with its continuous efforts to develop new magnesium alloys that will meet customer needs, the Company will also work to produce and promote magnesium alloys, environmentally friendly materials that could be substituted for steel and aluminum alloys.

*1 Die casting:
A casting process in which a molten metal is injected into a die under high pressure and quickly cooled and solidified into the final part. Owing to its high productivity, die casting is widely used for manufacturing aluminum automotive parts.

*2 Ingot: A mass of alloy that has been cast into a standard shape.

*3 Compressive creep characteristics:
Compressive creep is the tendency of parts to deform over time when they are fastened with bolts or other means and placed under a constant compressive stress. Since deformation of a metal usually increases with a rise in temperature, a material with high compressive creep characteristics would gradually reduce the tightening force of the bolts.