Process of manufacturing solid bodies of copper-zinc-aluminium alloys
AssigneeLeuven Research & Development VZW
InventorsAndre E. A. Deruyttere, Lucas J. A. E. Delaey, Etienne A. D. Aernoudt, Josef R. Roos
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Abstract
Solid bodies of copper-zinc-aluminium alloys having beta-crystal structure are manufactured by a powder-metallurgic process. Starting with a powder comprising 10-40% by weight of Zn, 1-12% by weight of Al and the balance Cu, the solid bodies are formed by means of a cold compacting step, an optional hot compacting step and a hot extrusion step.
Claims27
A process of preparing solid bodies of copper-zinc-aluminum alloys having a .beta.-crystal structure and a fatigue resistance of at least 100,000 cycles for a psuedo-elastic elongation of 0.8 to 1% under a maximum bending load of 250 MN/m.sup.2, which comprises the steps of providing a pulverulent material which consists essentially of unavoidable impurities, 10-40% by weight of Zn, 1-12% by weight of Al and the balance of Cu, cold compacting this pulverulent material and subsequently hot extruding it to form a solid body.
A copper-zinc-aluminum alloy article having a predominantly .beta.-crystal structure, an average grain size of down to about 20-30 .mu.m and a fatigue resistance of at least 100,000 cycles for a psuedo-elastic elongation of 0.8 to 1% under a maximum bending load of 250 MN/m.sup.2, and which is suitable for direct use and as an intermediate for further mechanical deformation to an end product having an average grain size not exceeding about 200 .mu.m;
- said article being made by a process which comprises:
- (a) mixing pulverulent material selected from the group consisting of elemental powders and/or alloy powders, said alloy article consisting essentially of 10-40% by weight of Zn, 1-12% by weight of Al, less than 0.2% by weight of oxygen and the balance of Cu,
- (b) cold compacting said mixture to form a self supporting mass,
- (c) heating said mass to a temperature of at least 700.degree. C. and
- (d) hot extruding said mass at an extrusion ratio of at least about 32 to yield said alloy article.
The method of making a Cu-Zn-Al alloy article which exhibits reversible shape memory effect, pseudo-elastic properties and, a fatigue resistance of at least 100,000 cycles for a psuedo-elastic elongation of 0.8 to 1% under a maximum bending load of 250 MN/m.sup.2, which comprises the steps of:
- (a) providing a pulverulent material which consists essentially of unavoidable impurities, 10-40% by weight of Zn, 1-12% by weight of Al, and the balance Cu in such proportions as will yield an alloy which, at room temperature, is predominantly of .beta.-crystal structure;
- (b) compacting the pulverulent material of step (a) at substantially ambient temperature to provide a coherent mass;
- (c) heating the mass of step (b) to a temperature in the order of 700.degree.-800.degree. C. and extruding said heated mass to form the article with a density of substantially 100%.
Dependencies are inferred from the claim text.