RECENT ADVANCES IN DESIGN OF ENERGY-CONVERSION SYSTEMS BASED ON DISPLACIVE MARTENSITIC TRANSFORMATIONS

Abstract
Uniaxial strain recovery associated with martensite-to-parent-phase structural reversion in NiTi has been applied to low-temperature energy conversion via solid state thermal engines. Special design considerations imposed by employing the material in this deformational mode are discussed with respect to the engineering properties of the material and the discontinous aspects of the reversion process. Within the last year, two engine prototypes based on this principle have been developed, and submitted to preliminary testing. Mechanical aspects of these designs are discussed in detail, and performance test results are analyzed. A specific potential commercial application for solid state solar thermal energy-conversion systems is identified, and recent developmental progress towards addressing this application is reported, with preliminary economic comparisons to competing technologies in the field.