INFLUENCE OF BETATIZATION HEAT TREATMENT ON MARTENSITIC TRANSFORMATION TEMPERATURE OF INDUSTRIAL COPPER BASED SHAPE MEMORY ALLOYS

摘要

The paper shows the effects of two types of long heat treatment at high temperature on copper based alloys with zinc or aluminium. The resulting increases of transformation temperatures seem to be governed both by loss processes and oxidation of the constitutive elements of the alloy. Different characterization techniques performed on heat treated samples demonstrate that the surface of the alloy plays an important role during betatization.