| 摘要 |
The invention relates to a semi-finished product, in particular of copper or copper alloys, which is produced from a rotationally symmetrical preform (1) by hot and cold forming steps. The preform (1) itself is produced by spray compacting and consists of a core (9) and at least one outer layer (10) which is disposed around said core, which, as a result of modifying additives, with the formation of a flowing boundary, have variable properties. Suitable modifying additives are particles which are insoluble in the metal matrix and are introduced either into the core (9) or into the outer layer (10), or they are heterogeneous insoluble particles which are introduced both into the core (9) and into the outer layer (10). <IMAGE> |
