STRAIN FIELD OBSERVATION AND LATTICE STABILITY AT THE TIP OF THERMOELASTIC CU-ZN-AL MARTENSITE PLATES

Transmission electron microscopy of the tapered martensite plates occurring in thin foils reveal a strong strain field contrast at the tip. The tip of the plate can be regarded as equivalent with a screw dislocation parallel to a less than 110 greater than // beta direction. Analysis of the elastic strain field ahead of the plates shows that the macroscopic shear deformation, (011) (0 OVER BAR 11), associated with those plates does not change the elastic constants for further deformation on the same shear system, but increases and decreases the elastic constants for deformations on the inclined shear systems of the type (110) (1 OVER BAR 10) and (101) (10 OVER BAR 1), respectively.