COPPER ALLOY AND ITS USES

Abstract

The invention relates to a copper alloy having the following composition (in % by weight): from 10.6 to 18% of Al, from 10.5 to 14.5% of Ni, optionally up to 2% of Fe, optionally up to 1% of Co, optionally up to 0.5% of Ti, optionally up to 0.5% of Mn, optionally up to 0.15% of B, optionally up to 0.1% of Ca, optionally up to 0.1% of C,

a balance copper and unavoidable impurities. Nickel aluminides of the NiAl type are embedded as precipitates in the microstructure of the alloy. The invention further relates to a number of uses of this copper alloy.

Claims

1. Copper alloy having the following composition in % by weight: from 10.6 to 18% of Al, from 10.5 to 14.5% of Ni, optionally up to 2% of Fe, optionally up to 1% of Co, optionally up to 0.5% of Ti, optionally up to 0.5% of Mn, optionally up to 0.15% of B, optionally up to 0.1% of Ca, optionally up to 0,1% of C, a balance copper and unavoidable impurities, characterized in that nickel aluminides of the NiAl type are embedded as precipitates in the microstructure of the alloy.

1. Copper alloy according to claim 1, characterized in that the proportion of aluminum is at least 12% by weight and not more than 16% by weight.

3. Copper alloy according to claim 1, characterized in that the proportion of nickel is at least 11% by weight and not more than 13% by weight.

4. Copper alloy according to claim 1, characterized in that the ratio of the proportion of aluminum in % by weight to proportion of nickel in % by weight is at least 0.95 and not more than 1.28.

5. Use of a copper alloy according to claim 1 for sliding elements.

6. Use of a copper alloy according to claim 1 for plug connectors.

7. Use of a copper alloy according to claim 1 for sealing elements.

8. Use of a copper alloy according to claim 1 for tools.

9. Use of a copper alloy according to claim 1 for spring elements.

10. Use of a copper alloy according to claim 1 for filter elements.

Description

[0044] The invention will be illustrated with the aid of working examples. Table 1 shows a compilation of alloy samples No. 1 to 8. The alloy composition in % by weight, the hardness, the electrical conductivity and the tensile strength are reported for each sample. With the exception of sample No. 6, which is present only in the cast state, the samples are present in the state immediately after hot forming in the temperature range from 600 to 800° C. at a degree of deformation of 20%. Samples No. 1 to 6 are comparative samples, and samples No. 7 and 8 have a composition according to the invention.

TABLE-US-00001 TABLE 1 Alloy samples No. 1 to 8 Al in Ni in Electrical Tensile Sam- % % conduc- strength ple by by Cu and tivity R.sub.m in No. weight weight impurities Hardness in IACS MPa 1 5.7 6.9 Balance 201 HV 11.7% 401 2 6.5 7.9 Balance 234 HV 13.3% 422 3 7.6 8.9 Balance 248 HV 13.4% 661 4 8.6 9.8 Balance 246 HV 13.5% 717 5 10.7 10.1 Balance 271 HV 12.7% 820 6 9.2 17.9 Balance 250 EV  8.0% — 7 11.1 11.2 Balance 280 HV 14.1% 830 8 13.9 12.1 Balance 300 HV 14.8% 1000

[0045] Samples No. 1 to 4 have a comparatively low proportion of aluminum and/or nickel. The tensile strength of these samples increases with an increasing proportion of aluminum and nickel and is significantly below 750 MPa. The electrical conductivity of samples No. 2 to 4 is at the same level. Sample No. 5 has an increased tensile strength and hardness compared to samples 2 to 4, but its electrical conductivity is reduced. In the case of sample No. 6, the proportion of nickel was made very high at 17.9% by weight. The hardness is approximately the same as the value for samples No. 3 and 4, but the electrical conductivity is at a lower level, namely 8% IACS.

[0046] Samples No. 7 and 8 according to the invention display unexpectedly good properties. If sample No. 7 is compared with No. 5, it is found that the strength has been increased further by increasing the proportions of aluminum and in particular of nickel, but the electrical conductivity has surprisingly also increased. The increase in the electrical conductivity in the case of sample No. 7 is not to be expected from the properties of samples No. 1 to 6. The best results were achieved in the case of sample No. 8. At about 14% by weight of aluminum and 12% by weight of nickel, a tensile strength of about 1000 MPa could be achieved in the hot-rolled state. The electrical conductivity is almost 15% IACS and is the highest value for all samples examined. The electrical conductivity of sample No. 8 could be increased further to almost 16% IACS by a heat treatment at 330° C. for 3 hours.

[0047] Sample No. 8 has a total of 26% by weight of alloying elements Al and Ni. Sample No. 6 has a total of about 27% by weight of alloying elements Al and Ni. The two samples thus have in total about the same proportion by weight of alloying elements. However, the properties of sample No. 8 are significantly better than those of sample No. 6. This shows that the alloying elements Al and Ni have to be selected in a particular relationship to one another. In the case of sample No. 8 the ratio of the proportions by weight of Al and Ni is about 1.15. Alloys having favorable properties are obtained when the ratio of Al to Ni is at least 0.95 and not more than 1.28.