Method for connecting shape-memory material and steel or copper material

Abstract

The process is to be used to connect a component made from a shape memory alloy to a thin component made from steel material or a copper material. The intention is to provide a spot-welding technique using electrodes made from a Cu alloy. The intention is to establish a current intensity of over 1000 A, preferably over 2000 A, at an I 2 t value of over 5000 A 2 s, preferably over 8000 A 2 s, and a pressure of at least 30 MPa, preferably 80 MPa.

1 . A process for producing a mechanical and electrical connection between a component made from a shape memory alloy and a thin component made from an optionally coated steel material or a copper material, characterized in that a spot-welding technique is provided using electrodes made from a Cu alloy, a current intensity of over 1000 A at an I 2 t value of over 5000 A 2 s and a pressure of at least 30 MPa being established.  
     
     
         2 . The process as claimed in  claim 1 , characterized in that a current intensity of over 2000 A is established.  
     
     
         3 . The process as claimed in  claim 1  or  2 , characterized in that an I 2 t value of over 8000 A 2 s is established.  
     
     
         4 . The process as claimed in one of the preceding claims, characterized in that a pressure of at least 40 MPa, preferably of at least 80 MPa, is established.  
     
     
         5 . The process as claimed in  claim 1 , characterized in that a current intensity of approximately 2000 A, an I 2 t value of approximately 10000 A 2 s and a pressure of approximately 150 MPa are established, said values each being maintained to an accuracy of ±10%.  
     
     
         6 . The process as claimed in one of the preceding claims, characterized in that the electrode material provided is a Cu alloy which, in addition to Cu as its main constituent, also contains at least one of the elements Ag, Be, Co, Cr, Cd, Fe, Hf, Mn, Mo, Nb, Pd, Pt, Ta, Ti, V, W, Zn, Zr.  
     
     
         7 . The process as claimed in  claim 6 , characterized in that the electrode material provided is a CuCoBe alloy.  
     
     
         8 . The process as claimed in  claim 7 , characterized in that the electrode material provided is a Cu x Co y Be z  alloy, where 50≦x≦99.8, 0.1≦y≦20 and 0.1≦z≦20, with x+y+z≈100 (in each case in atomic %) with the inclusion of small amounts of impurities, in each case amounting to less than 1 atomic %.  
     
     
         9 . The process as claimed in one of the preceding claims, characterized in that a component made from the steel material or the copper material with a thickness of between 0.1 and 5 mm, preferably 0.5 and 2 mm, is provided.  
     
     
         10 . The process as claimed in one of the preceding claims, characterized in that a component made from a copper-plated steel sheet is provided.  
     
     
         11 . The process as claimed in one of  claims 1  to  9 , characterized in that a component made from a stranded copper conductor made from copper or a copper alloy is provided.  
     
     
         12 . The process as claimed in one of the preceding claims, characterized in that the shape memory alloy provided is a TiNi or TiNiCu or TiNiPd or CuAl or CuAlNi or CuAlZn alloy which, if appropriate, also contains further components, in each case in an amount of less than 5 atomic %.  
     
     
         13 . The process as claimed in  claim 12 , characterized in that a shape memory alloy to which Hf is alloyed is provided.