REORIENTATION IN COMBINED STRESS-INDUCED MARTENSITE

The thermoelastic martensitic transformation induced by independent ex ternal forces has been investigated in combined tension-torsion experi ments with Cu-Al-Zn-Mn SMA hollow bar polycrystals. When the nonpropor tional change of the applied stress (reloading) occurs at low volume f raction of stress induced martensite phase, the shape of the experimen tal transformation path suggests, that the forward or reverse stress i nduced martensitic transformations take place, depending whether the m echanical energy is being supplied or released. At higher volume fract ion of martensite, the deformation behavior upon reloading becomes mor e complex, suggesting a possible role of martensite to martensite tran sformations or reorientation processes.