Spontaneous emf associated with shape memory effect in TiNi

摘要

A transient emf of approximately 0.1 mV lasting for about 100 msec is observed at the ends of a coldhyphen;stressed TiNi wire when a central portion of the wire is rapidly heated to above its shape memory transition temperature. A pulse of opposite polarity is observed during cooling through the transition temperature when the temperature change is coincident with a shape change. The polarity of the voltage is inverted when the electrical leads are reversed, implying that the wire is itself polarized. The observed emf is enhanced in a wire which has been rsquo;rsquo;trainedrsquo;rsquo; so that it displays a double memory.