Time Evolution in Static β-Phase and Dynamic β-Martensite Coexistence (Cu-Zn-Al SMA)
CIRG-DFA-ETSECCPB-UPC, 08034 Barcelona, Spain
2 Div. Metales, CAB, 8400 S.C. Bariloche, Argentina
The application of a SMA implies an accurate knowledge about the eventual time - behavior of the alloys. The effects of quenching and micro-heatings were studied by calorimetric and resistance measurements and the β-martensite coexistence by stress - strain - temperature - time observations. Experimental analysis was performed using copper based single crystals (Cu-Zn-Al, e/a ≈ 1.48 e/a with Ms below room temperature). The phenomenological behavior establishes several time constants for each evolution. A change ΔT of temperature of the parent phase near 300 K induces an asymptotic time evolution on Ms near 11 per cent. The parent to martensite coexistence produces an evolution of the equilibrium temperature (near 0.5 K) linked to the existence of an interface.
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