Metallurgy, Vol. 66 No. 2, 2027.
Original scientific paper
https://doi.org/https://doi.org/10.64486/m.66.2.3
Phase-State Control in As-Cast Cu–Al–Mn Shape Memory Alloys
Lovro Cigić
; University of Ljubljana, Faculty of Natural Sciences and Engineering (UL NTF), Aškerčeva cesta 12, 1000 Ljubljana, Slovenia
*
Aleš Nagode
; University of Ljubljana, Faculty of Natural Sciences and Engineering (UL NTF), Aškerčeva cesta 12, 1000 Ljubljana, Slovenia
Ivana Ivanić
; University of Zagreb, Faculty of Metallurgy, Aleja narodnih heroja 3, 44000 Sisak, Croatia
Borut Kosec
; University of Ljubljana, Faculty of Natural Sciences and Engineering (UL NTF), Aškerčeva cesta 12, 1000 Ljubljana, Slovenia
Blaž Karpe
; University of Ljubljana, Faculty of Natural Sciences and Engineering (UL NTF), Aškerčeva cesta 12, 1000 Ljubljana, Slovenia
*
* Corresponding author.
Abstract
Cu–Al–Mn shape memory alloys (SMAs) are attractive functional materials owing to their thermoelastic martensitic transformation, which enables the shape memory ef-fect, superelasticity, and elastocaloric response. However, their practical application requires precise control of the transformation temperatures. In this study, the effect of Sn addition on the chemical homogeneity, microstructure, hardness, and transfor-mation temperatures of as-cast Cu–Al–Mn–Sn alloys was investigated. CuAl9Mn9.5-based alloys with different Sn contents were fabricated by suc-tion-assisted gravity casting, and their compositions were analyzed by ener-gy-dispersive X-ray spectroscopy. Differential scanning calorimetry revealed that Sn addition systematically decreased the Ms, Mf, As, and Af temperatures. A pronounced shift was already observed after adding 0.78 wt. % Sn, which reduced Af from 102.4 to 23.4 °C. Further Sn additions shifted the transformation interval into the sub-zero temperature range, with Af reaching −61.1 °C at 2.62 wt. % Sn. The transfor-mation-temperature changes were accompanied by a transition from martensitic to austenitic room-temperature microstructure and increased hardness. These results demonstrate that Sn addition is an effective approach for tailoring the transformation temperature range of Cu–Al–Mn SMAs while maintaining casting consistency and chemical uniformity.
Keywords
Cu–Al–Mn shape memory alloy; Sn alloying; transformation temperatures; differen-tial scanning calorimetry
Hrčak ID:
352419
URI
Publication date:
1.4.2027.
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