Patent ID: 8088233

Claim:
A method of characterizing phase transformations of a shape memory alloy comprising an R-phase transformation, the method comprising: recording data from a specimen comprising a shape memory alloy during heating and cooling, the shape memory alloy having an R-phase transformation, the heating and cooling comprising: cooling the specimen to a first temperature sufficient to define a first inflection and a second inflection in the data being recorded, the first inflection occurring over a first temperature interval and corresponding to a phase transformation from austenite to R-phase and the second inflection occurring over a second temperature interval and corresponding to a phase transformation from R-phase to martensite; heating the specimen to a second temperature sufficient to define a third inflection in the data being recorded, the third inflection occurring over a third temperature interval and being formed by overlapping primary and secondary sub-inflections corresponding respectively to phase transformations from martensite to R-phase and from R-phase to austenite; cooling the specimen to a third temperature sufficient to define the first inflection in the data being recorded but not sufficient to define the second inflection, whereby the shape memory alloy has a substantially fully R-phase structure; heating the specimen to a fourth temperature sufficient to define the secondary sub-inflection in the data being recorded, the secondary sub-inflection corresponding to the phase transformation from R-phase to austenite.