Effect of Heat Treatment on Microstructure and Thermal Properties of Cu-based Shape Memory Ribbons

Abstract

The aim in this work was to investigate the change in microstructure, phase transformation temperatures, and thermal properties due to the quenching of the investigated Cu-Al-Mn and Cu-Al-Mn-Ti alloys in ribbon form. This paper presents the results of microstructure analysis and thermal properties of Cu-Al-Mn and Cu-Al-Mn-Ti shape memory alloys produced in ribbon form by melt spinning technique. The microstructural analysis was carried out before and after quenching. After casting of the investigated alloys, annealing at 900 °C for 30 min was performed, followed by water quenching. The microstructural analysis was carried out by optical and scanning electron microscopy equipped with an energy dispersive spectrometer and by X-ray diffractometer. Thermodynamic calculation of a ternary Cu-Al-Mn system in equilibrium condition was performed using Thermo-Calc 5 software. Phase transformation temperatures were determined by differential scanning calorimetry and electrical resistance measuring. The results of microstructural analysis show the presence of martensite microstructures before and after quenching in the Cu-Al-Mn alloy, while in the Cu-Al-Mn-Ti alloy martensite microstructure exists only after quenching. Phase transformation temperatures decreased after quenching and titanium addition.

Razvoj legura s prisjetljivošću oblika na bazi bakra u okviru znanstveno-istraživačkih projekata na Metalurškom fakultetu Sveučilišta u Zagrebu

“…%) pokazalo je da titanij znatno snižava temperaturu martenzitne transformacije u odnosu na ternarnu leguru SMA. 44 Utvrđeno ja da mikrolegiranje ternarne legure niklom doprinosi intenzivnom stvaranju martenzitne transformacije u lijevanom i austenitiziranom uz naknadno gašenom stanju, s nižom temperaturom početka formiranja martenzita nakon toplinske obrade i austenitizacije uz naknadno gašenje materijala. 45 Rezultati mehaničkih svojstava vertikalno kontinuirano lijevane legure Cu-8,3Al-9,4Mn za duge proporcionalne epruvete (po tri epruvete za svako stanje) prikazani u tablici 2 ukazuju na to da toplinska obrada također znatno utječe na vlačnu čvrstoću i istezanje legure.…”

Rapid solidified ductile Cu-Al-Mn ribbon and its elastocaloric potential

“…However, studies on melt-spun copper-based ribbons are rare and focused mainly on the transition temperatures [45][46][47][48]. There has been renewed interest in melt-spun ribbons, and a recent work reported the microstructure and thermal properties of copper-based ribbons after heat treatment [49]. This work systematically studied the order-disorder transition, microstructure, tensile property, phase transformation characteristics, and elastocaloric potential for melt-spun Cu-Al-Mn ribbons.…”