SELF-ACCOMMODATION AND SHAPE MEMORY MECHANISM OF EPSILON-MARTENSITE .1. EXPERIMENTAL-OBSERVATIONS

Experimental aspects of the self-accommodation of epsilon-martensite variants have been investigated using transmission electron microscopy. Characterization of the faulting configuration of martensitic substructures confirms that the spontaneous martensitic transformation is generally self-accommodating, although involving localized homogeneous shears which often result in the formation of secondary variants at intersections. Stress-induced transformation promotes the growth of a single preferred variant, either at the expense of others within a band Or by the formation of secondary variants at intersections between different bands. In Part II, based on these experimental observations, theoretical considerations of self-accommodation and the shape memory mechanism of epsilon-martensite will be discussed in comparison with the well-known Cu-based shape memory alloys.