APPRAISAL OF RECENT WORK ON ROLE OF CRYSTALLOGRAPHY IN FERROUS AND NONFERROUS PEARLITE

Work on pearlite up to 1962 is briefly outlined and work on the crysta llography of pearlite before 1984 is discussed. Studies of the heterop hase boundaries in ferrous and non-ferrous pearlite by transmission el ectron microscopy over the past decade are introduced. The 'ledge grow th mechanism' based on such studies is evaluated against the 'classic' view of pearlite growth. It is concluded that the hypothesis of the l edge growth mechanism offers a comprehensive explanation of pearlite p henomena and that the classic view fails to account for some features of pearlite. The implications of the new research on pearlite are addr essed. The details of ledge motion and the velocity-spacing problem ar e discussed. The lack of work on the importance of crystallography on morphological evolution of pearlites is identified. Further work neces sary to evaluate and advance the new understanding of pearlite is outl ined. (C) 1995 The Institute of Materials.