engleski

The Influence of Heat Treatment on Microstructure and Phase Transformation Temperatures of Cu-Al-Ni Shape Memory Alloy

In this paper the results of thermal and microstructural analysis of CuAlNi shape memory alloy before and after heat treatment were presented. The bar of the Cu-12.8 Al – 4.1 Ni (wt.%) alloy obtained by vertical continuous casting technique after casting was submerged to a certain heat treatment procedure. The solution annealing at 850 °C was performed, holding on that temperature for 60 minutes and following water quenching. Afterwards, the tempering at four different temperatures (150 °C, 200 °C, 250 °C and 300 °C) was performed. The microstructural results were obtained by optical and scanning electron microscopy. Thermodynamic calculation of ternary Cu-Al-Ni system under equilibrium is performed by software Thermo-Calc 5. Phase transformation temperatures were determined by differential scanning calorimetry (DSC). The DSC results show the highest values of transformation temperatures in as-cast state. After solution annealing and tempering the transformation temperatures show lower values with exceptional stability of Ms temperature (martensite start temperature).

shape memory alloy, CuAlNi, heat treatment, phase transformation, microstructure

Glavni autor: Ivana Ivanić, Stjepan Kožuh