Strain induced martensite stabilization in β Ti-Zr-Nb shape memory alloy

An unusual phenomenon of strain induced martensite stabilization in the β-type Ti-30Zr-10Nb shape memory alloy was studied. The strain induced α″-martensite formed in the β phase during the tensile loading on the metastable Ti-30Zr-10Nb alloy. It was stabilized at room temperature and thus no superelastic recovery occurs in the alloy upon unloading. The reverse transformation temperature of the strain induced α″-martensite increased from 333 K to 369 K with increasing pre-strain from 2% to 8%. Shape memory recovery occurred in the pre-strianed Ti-30Zr-10Nb alloy upon heating. The maximum shape memory effect of the alloy was 3.5% with the pre-strain of 8%.