Method for Producing a Copper Alloy Having a High Damping Capacity

Abstract

The invention relates to a copper alloy which is used for mechanically stressed components which, during operation, are subjected to vibrations and/or impacts to produce the same, and have particularly good mechanical damping properties. The composition of said copper alloy depends upon the utilisation temperature or working temperature of the component. Said copper alloy consists of 2-12 wt.-% manganese, 5-14 wt.-% aluminum and individually or in total 0-18 wt.-% of one or several elements, nickel, iron, cobalt, zinc, silicon, vanadium, niobium, molybdenum, chromium, tungsten, beryllium, lithium, yttrium, cerium, scandium, calcium, titanium, phosphorous, zirconium, boron, nitrogen, carbon, whereby each element does not contain more that 6% and 100 wt.-% copper. The alloy is obtained by adapting the martensite-austenitic conversation temperatures or the associated intervals M S -M F and/or A S -A F to a predetermined utilisation temperature or working temperature of the component by varying the weight proportion of the above-mentioned alloy component during melting thereof. The damping can reach above 70%.

1 . A process for producing a Copper alloy having specifically improved mechanical damping for mechanically stressed components, which comprises, as constituents of the alloy, from 2 to 12% by weight of manganese, from 5 to 14% by weight of aluminum and, individually or together, from 0 to 18 by weight of one or more of the elements nickel, iron, cobalt, zinc, silicon, vanadium, niobium, molybdenum, chromium, tungsten, beryllium lithium, yttrium, cerium, scandium, calcium, titanium, phosphorus, zirconium, boron, nitrogen, carbon, but each element in an amount of not more than 6%, and copper to 100% by weight, characterized in that
 a) a composition for the alloy is selected and the constituents are melted in a Customary way at a suitable temperature,   b) during this melting, at least one of the marten-sjtjc and austenitic transformation temperatures M S , M F , A S  and A F  is determined on a sample taken from the melt,   C) these transformation temperatures are increased or reduced on the basis of a predetermined use or working temperature of the component by targeted addition of at least one constituent of the alloy and thus matched to the use or working temperature,   d) the new transformation temperatures and, if appropriate, ranges are checked by means of a further sample and   e) the alloy is cast into the desired mold.   
   
   
       2 . The process as claimed in  claim 1 , Characterized in that the steps c) and d) are repeated as often as necessary. 
   
   
       3 . The process as claimed in  claim 1 , characterized in that correction of the transformation temperatures is carried out during melting by addition of copper or aluminum. 
   
   
       4 . The process as claimed in  claim 1 , characterized in that the transformation temperatures are set so that the temperatures in the middle of the martensitic or austenitic range of the phase transformation are very close to the predetermined use or working temperature. 
   
   
       5 . The process as claimed in  claim 1 , characterized in that the alloy in the form of a Shaped part obtained initially by Casting or forging and if appropriate forming is subjected to heat treatment at temperatures of from 650° C. to 950° C. and subsequent cooling or quenching in liquid or gaseous media, in particular air, liquid nitrogen, water, a salt bath or oil. 
   
   
       6 . The process as claimed in  claim 5 , characterized in that the temperature of the quenching medium is above the M S  temperature of the alloy. 
   
   
       7 . The process as claimed in  claim 1 , characterized in that the alloy in the form of a shaped part obtained initially by casting or forging and if appropriate forming is heat treated/aged at a temperature of from 100 to 300° c. for from about 5 to 120 minutes. 
   
   
       8 . The process as claimed in  claim 1 , characterized in that the alloy is subjected to one or more thermal cycles between the austenitic state and the martensitic state and back. 
   
   
       9 . The process as claimed in  claim 1 , characterized in that heat treatment of the outer layer of a shaped part obtained from the alloy by casting or forging and if appropriate forming is effected by means of laser remelting of the outer zone. 
   
   
       10 . The process as claimed in  claim 1 , characterized in that the sample for quick monitoring of the transformation temperatures is taken by means of a fused silica tube in which a subatmospheric pressure is produced. 
   
   
       11 . The process as claimed in  claim 1 , characterized in that the transformation temperatures are determined on the sample by calorimetry, dilatometry, measurement of the electrical conductivity, optical microscopy or measurement of the acoustic emission. 
   
   
       12 . The process as claimed in  claim 1 , characterized in that the damping behavior is additionally influenced by targeted alteration of the grain size. 
   
   
       13 . A copper alloy, in particular for mechanically stressed components, having specifically improved mechanical damping, which comprises, as constituents of the alloy,
 from >4 to 12% by weight of manganese,   from >10 to 14% by weight of aluminum,   from 0.01 to 0.8% by weight of chromium and,   individually or together,   
     from 0 to 18% by weight of one or more of the elements nickel, iron, cobalt, zinc, silicon, vanadium, niobium, molybdenum, chromium, tungsten, beryllium, lithium, yttrium, cerium, scandium, calcium, titanium, phosphorus, zirconium boron, nitrogen, carbon, but each element in an amount of not more than 6%, and copper to 100% by weight. 
   
   
       14 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 1 to 4% by weight of nickel. 
   
   
       15 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 11.6 to 12% by weight, preferably about 11.8% by weight, of aluminum. 
   
   
       16 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 8 to 10% by weight of manganese. 
   
   
       17 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 2 to 4% by weight of iron and/or from 0.001 to 0.05% by weight of boron. 
   
   
       18 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 0.01 to 1% by weight of cobalt. 
   
   
       19 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 0.01 to 0.3% by weight of rare earths. 
   
   
       20 . The copper alloy as claimed in  claim 13 , characterized in that the alloy contains from 2 to 6% by weight of zinc. 
   
   
       21 . (canceled) 
   
   
       22 . (canceled)