Semi-solid processing is a new technique for producing near-net shape components for high performance applications from aluminum, magnesium and copper-alloys, as well as from metal matrix composites.

Rather than using liquid metal, semi-solid processing uses metal that is partially solid and partially liquid. This semi-solid feed material has a consistency similar to ice cream or room temperature butter, so it can be injected into a steel die using relatively low pressures. The high viscosity of the semi-solid metal, along with the use of controlled die filling conditions, ensures that the semi-solid metal fills the die in a non-turbulent manner so that harmful porosity and other defects are essentially eliminated.

Dr. Midson has hands-on experience with many aspects of semi-solid processing, such as:

  • Managing a semi-solid manufacturing facility.
  • Performing research on many aspects of semi-solid processing, including feed material, microstructural development, billet re-heating, alloy development and component making. Published research results in technical journals and at conferences around the world.
  • Prototyped numerous components, exceeding customerís mechanical property and functional requirements for the parts.
  • Installed and started-up semi-solid casting cells at clientís facilities.
  • Co-organizer of international semi-solid casting conference held in 1998 in Golden, Colorado.

Dr. Midson has experience with the three different semi-semi-solid processes currently being used for the commercial production of components. These are:

Thixoforming, which re-heats billet feed material to the semi-solid forming temperature, producing extremely high quality aluminum components.

Rheocasting, which cools a liquid feed material to the semi-solid processing temperature, producing high quality, inexpensive aluminum and copper alloy components. There are a number of different rheocasting processes in commercial production or under development.

Click here to see a list of 20 different rheocasting processes

Thixomolding uses an injection molding type machine to produce thin-walled, near-net shape components from magnesium alloys.