| 摘要 |
The invention concerns a copper alloy which is characterised by a shape memory, high tensile strength, high extension capability and very high degree of shape recovery. There is a variety of shape memory alloys known worldwide, including those based on copper. These include brass. One of the well known types of brass is aluminium brass containing by weight around 14% of zinc, around 18% of aluminium or 23-24% of zinc and 78% aluminium / N. Mantel, R. Rapationi, G. Guenin - Revue de Metalurgie, February 1988, p. 97/. Another known type of an alloy contains about 26% by weight zinc and about 4% by weight aluminium /D. A. Admyana - Wire Journal International, April 1984, p. 52/ In comparison to the traditional nickel-titanium alloys they have one basic disadvantage - low mechanical properties. Their extension capability does not exceed 250 Mpa. The other bad point is that they are difficult to be formed while cold. In order to improve these properties they are supplemented with elements like vanadium /K. Enami, N. Takimoto, S. Nenna - Journal de Physique 43. 1982. 785, append. 12/, cerium, chrome, zirconium /Y. Ikami, K. Marakami, K. Mishima - Journal de Physique 43. 1982. 785, append. 12/ or a special heat treatment is applied /S. M. White, J. M. Cook, W. M. Strobbs - Journal de Physique 43. 1982. 779, append. 13/. The additives listed above or the heat treatment reduce partly the faults, however, their application implies technological difficulties. The aluminium brass being subject of this invention is characterised by the fact that it contains: 8-30% of zinc, 2.5-18% of aluminium, 0.001-0.5% of boron, the rest is composed of copper and allowable impurities amounting up to 0.8%. This alloy can be produced by known methods of melting and static, continuous and semi-continuous casting followed by plastic heat working including extrusion, rolling, open or closed die forging, plastic cold working including rolling, drawing and deep drawing and heat treatment by hardening, toughening and annealing.
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