THE MECHANICAL-BEHAVIOR OF AND DEFORMATION MECHANISMS IN AL2TI

The mechanical properties of the binary intermetallic compound AI,TI s how a strong dependence on test temperature and processing condition. The compressive yield strength and plastic strain-to-failure of AI,Ti as a function of temperature will be reviewed. Unlike many L1(2) compo unds, binary Al2Ti with the Ga2Hf crystal structure, a body-centered t etragonal-based structure, does not show any evidence of anomalous yie ld strength behavior. Based on the crystallography of Al2Ti, various d eformation modes are proposed. Possible partial dislocations and the p lanar faults that would be associated with them are hypothesized. The formation of antiphase boundaries (APBs) on {1 1 6}-the close-packed p lanes-and {1 0 0} and complex stacking faults (CSFs) on {1 1 6} will b e discussed. It does not appear to be possible to form a superlattice intrinsic stacking fault (SISF) on {1 1 6}. Slip by 1/2(1 1 0) partial dislocations on {0 0 1} with the formation of a stacking fault may al so be an important deformation mechanism and will be discussed. Therma lly-activated cross-slip of APE-coupled partial dislocations from {1 1 6} onto {1 0 0} is not expected to be important in this material base d on the observed mechanical behavior. (C) 1997 Elsevier Science S.A.