Abstract: A mechanically rigid joint is formed between two different metals by completing the joint in a forging operation. A part (14) made of one metal is placed in a die form (20) and is maintained at a temperature below that required for forging. A billet (23) made of the material from which the second part (13) is to be formed is coated with boron nitride at an interface (16). The boron nitride is thermally treated while on the billet (23) by heating the coated billet (23) in a non-oxidizing atmosphere. The billet (23) may then be heated and placed in the die (20) so that the billet (23) can be formed into the second part (13), engaging the first part (14) at an interface (16) defining the joint. The joint (16) is stabilized by providing suitable coatings for the materials, particularly at the interface (16).

Abstract: A mechanically rigid joint is formed between two different metals by completing the joint in a forging operation. A part (14) made of one metal is placed in a die form (20) and is maintained at a temperature below that required for forging. A billet (23) made of the material from which the second part (13) is to be formed is placed in the die (20) so that the billet (23) can be formed into the second part (13), engaging the first part (14) at an interface (16) defining the joint. The joined parts (13, 14) are then machined into their final shape. The joint (16) is stabilized by maintaining appropriate temperatures of the materials to compensate for expansion and contraction after forging, and by providing suitable coatings for the materials, particularly at the interface (16).