Method for making metal alloy compositions and composition

US4295896A · kind A · utility

Assignee

• Massachusetts Institute of Technology · US

Inventors

• Merton C. Flemings · Cambridge, US
• Frank E. Goodwin · Chapel Hill, US

Key dates

• Filing date: May 14, 1979
• Grant date: Oct 20, 1981
• Expiry date: May 14, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C1/12
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Metal compositions having significantly improved mechanical properties and substantially free of second phase material are produced by heating a metal alloy from the non-equilibrium solidus temperature while subjecting the liquid-solid mixture to high pressure and forcing the liquid through a filter. The solid is rapidly quenched to retain solutes in solid solution or the solid is heat treated to permit solution of remaining secondary phase material followed by rapidly quenching the heat treated alloy. The solid then is re-heat treated at low temperature to permit age hardening. If the material is to be used in wrought form, it may be worked at any stage of the processing after interdendritic liquid is removed. The process can be used to work as semi-solid metal compositions which previously have been thought unworkable, to reduce the composition differences between regions of primary phases, to remove phase and impurities known to reduce the strength of alloys, and to modify the structure of the solid phase of alloys. Metal compositions which previously have only been made with structures containing secondary phases material present have been made with substantially no secondary p…