SHAPE MEMORY EFFECT IN 2-PHASE ALPHA/BETA-CUZNAL ALLOY

The effect of betatisation temperature in dual phase (alpha+beta) region on transformation temperatures A(s), M(s) volume fraction of martensite and one way shape memory effect have been studied in Cu22Zn6,65Al(wt%) alloy. The effect of postquenching heating on stabilisation of martensite was observed, too. It was found that while after betatisation at lower temperature (650-700-degrees-C) R18 martensite was observed, betatisation at 740-degrees-C resulted in R9 martensite. The X-ray diffraction showed that stabilisation resulted in changes of crystalline lattice of martensite. The surprising decreasing of shape memory effect with increasing betatisation temperature is attributed to following superimposed effects: the change of chemical composition of beta phase along with the change of transformation temperatures, the stabilisation of martensite and probably volume fraction of untrasformed retain beta phase in region between alpha phase and martensite.