HIGH-RESOLUTION ELECTRON-MICROSCOPY STUDY ON THE SUBSTRUCTURE OF TI-NI-HF B19' MARTENSITE

The substructure of martensite in the Ti,,Ni,,Hf,, alloy has been inve stigated by high-resolution electron microscopy (HREM) and discussed w ithin the framework of a phenomenological theoretical analysis. The (0 01) compound twins and (001) stacking faults were confirmed to be the main substructure inside a martensite variant with some (011) stacking faults infrequently observed. The (001) twinning boundary was straigh t with some blurred regions and (001) faults existing near the interfa ce. The (001) compound twin alone is shown to be unable to produce the lattice invariant shear necessary for the martensitic transformation. (C) 1998 Elsevier Science B.V. All rights reserved.