Adiguzel O
Heat treatment, homogenization and phase transformations have great importance in the processing of materials as a tool in industry and other fields. Shape memory effect is a temperature dependent phenomenon exhibited by certain alloy systems called shape memory alloys. These alloys have dual characteristics called thermoelasticity and superelasticity. Thermoelasticity is governed by thermal and stress induced martensitic transformations on cooling and stressing and performed thermally on heating and cooling after first cooling and stressing processes. Superelasticity is governed by stress induced transformation by stressing and releasing materials at a constant temperature in parent phase region. Shape memory alloys can be plastically deformed with external stress in the low temperature product phase condition and recover the original shape on heating, and cycle between original and deformed shapes in reversible way, on cooling and heating, respectively. Shape memory effect involves a crystallographic phase transformation, martensitic transformation, on cooling and reverse austenitic transformation on heating.