The intention in presenting this paper is to outline the main trends in recent alloy development and to indicate the current state of the art as far as the user is concerned, particularly on the behaviour of the new products in the problem areas so designated by the engineering metallurgists and materials specialists in the industry.

In reviewing recent alloy development it is convenient to identify two main lines in terms of the metallurgical structures involved, since these tend to define the more appropriate areas for design interest.