Copper-niobium alloy and method for the production thereof

Abstract

The invention relates to the field of materials engineering and relates to copper-niobium alloys which can be used for producing powder metallurgical products by known shaping methods, e.g., after having been processed into semi-finished products or shaped bodies, and a method for the production thereof. The object of the invention is to disclose copper-niobium alloys and a method for the production thereof in which a homogenous metastable Cu mixed crystal is present and a method for its implementation. The object is attained through a copper-niobium alloy in which, in addition to a copper-niobium mixed crystal, niobium deposits with particle diameters of 5-100 nm are also present in a copper matrix. The object is further attained through a method for producing copper-niobium alloys in which copper powder as matrix material and 0.1 to 50 at. % niobium powder are jointly ground and mechanically alloyed and then subjected to at least one thermal treatment.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of International Application No. PCT / DE03 / 00764, filed Mar. 3, 2003, and claims priority under 35 U.S.C. § 119 of German Patent Application No. 102 10 423.9 filed on Mar. 4, 2002. Moreover, the disclosure of the International Patent Application No. PCT / DE03 / 00764 is expressly incorporated by reference.FIELD OF ART [0002] The invention relates to the field of materials engineering and relates to copper-niobium alloys which can be used for producing powder metallurgical products by known shaping methods, e.g., after having been processed into semi-finished products or shaped bodies, and a method for the production thereof. PRIOR ART [0003] In order to produce a metallic material with the highest possible mechanical strength and electrical and thermal conductivity, in addition to silver, which has the highest electrical conductivity of all metals, copper is mainly used as a matrix metal because of its much...

AI Technical Summary

Benefits of technology

[0016] It is also advantageous if the cooling of the grinding vessel is carried out during grinding and / or between the grinding stages.

[0017] Furthermore it is advantageous if the grinding vessel is cooled with liquid nitrogen or with ethanol.

[0018] It is furthermore advantageous if a complete forcible solution of the niobium in the copper lattice is carried out during grinding.

[0022] It is also advantageous that a high powder yield of the copper-niobium alloy is produced.

[0023] It is also advantageous if grinding is carried out for between 20 and 30 hours.

[0026] After the niobium atoms have been dissolved in the copper mixed crystal, fine niobium particles are deposited during the subsequent thermal treatment. These niobium deposits substantially contribute to increasing the strength and ensuring a high conductivity of the alloy.

Problems solved by technology

However, due to the difference in density and melting point present, a homogenous distribution of the respective secondary phase and the particle size distribution in the nanometer range necessary for an efficient increase in strength cannot be achieved through metallurgical fusion methods.

With mechanical alloying the grinding progress results from repeated fracturing and cold-welding of the powder particles.

However, due to the increase in temperature during grinding, with such alloy systems in general there is a danger of the powders adhering to the wall of the vessel and to the balls, which leads to a low powder yield.

If this gas is not removed by degassing annealing at high temperatures, a consolidation of the powders into dense compact semi-finished products is not possible or leads to shape instability (“swelling”) during later use at high temperatures.

On the other hand, the nanocrystalline grain structure intentionally established in the powder is destroyed through an upstream degassing annealing.

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