Bbc Brown, Boveri & Company, Limited

Bbc Aktiengesellschaft Brown, Boveri & Cie

Helmut Riegger

Olivier Mercier

Keith N Melton

Gernot H Gessinger

Oliver Mercier

Shape-memory alloys comprised of Cu/Al or Cu/Al/Ni are produced by a powder metallurgical process wherein a coarse-grained powder of pre-alloyed and/or pre-mixed powder alloys having a grain size of 0.05 to 0.8 mm is introduced into a metal container which is then evacuated, sealed, and hot isostatically pressed. The resulting billet is then hot worked. In another embodiment, the powder is first placed in a rubber tube and cold isostatically pressed. The billet is then placed in a cylinder having deformable walls, such as a copper cylinder, the cylinder is sealed, and the powder therein is then hot isostatically pressed, and the billet so prepared is subjected to a homogenization heat treatment and hot working.

Powder metallurgical process for producing a copper-based shape-memory

Shape-memory alloy based on copper, zinc and aluminum and process for

Fine grained copper-based or nickel-based memory alloys having a matrix of .beta.-high temperature phase with metal oxide particles dispersed in the matrix which act to retard grain growth have improved mechanical characteristics such as elongation, toughness and workability, compared to cast and worked alloys. These alloys are produced by powder metallurgy.

Memory alloys based on copper or nickel solid solution alloys having

Cu/Al and Cu/Al/Ni memory alloys having improved mechanical properties are prepared by powder metallurgy from mixtures of pre-alloyed and/or pre-mixed powder ingredients. The mixture of powder ingredients is subjected successively to isostatic pressing, sintering in an inert atmospheric and subsequent multi-step hot working with intermediate annealing which serves to homogenize. Final annealing is carried out in the .beta.-phase solid solution temperature range and the annealed article is quenched in water.

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Busslingen, Switzerland

Helmut Riegger