Characterization of {001} stacking faults in Al67Ni8Ti25

Abstract

Intermetallic alloys with compositions near Al₆₇Ni₈Ti₂₅ have the cubic L1₂ crystal structure, in contrast with Al₃ Ti which has the tetragonal D0₂₂ structure. Features exhibiting stacking-fault-like contrast were observed on {001} planes in an Al₆₇Ni₈Ti₂₅ intermetallic alloy after annealing at 1050°C. Characterization of the features using transmission electron microscopy revealed that they are intrinsic stacking faults on {001} planes, which result from dissociation of a₀{001} dislocations. The displacement vector associated with the faults was determined to be approximately 0.4a₀. Computer-simulated electron micrographs were instrumental in identifying the fault characteristics. The fault characteristics reveal that they are sessile and thus do not directly participate in deformation processes in this intermetallic alloy.