https://doi.org/10.1140/epjp/s13360-024-05352-3
Regular Article
Study of the stabilization of ordered austenite β1 in Cu79Al19X2 (X = Be or Mn) alloys
Universidade Federal de São Paulo (UNIFESP), 09910-720, Diadema, SP, Brazil
Received:
5
March
2024
Accepted:
10
June
2024
Published online:
22
June
2024
The knowledge of the fundamentals that guide the well-known shape memory effect is fundamental for the development of devices that use this material ability. At the center of this discussion are the phase transitions related to the β phase, which originate the martensite. In this work, ordered austenite (β1 phase) stabilization in Cu-rich CuAlMn and CuAlBe alloys is discussed comparatively to expand the ideas known about these materials. Austenite stabilization was investigated in as-quenched Cu81Al19, Cu79Al19Be2, and Cu79Al19Mn2 alloys by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, differential scanning calorimetry, and Vickers microhardness measurements. The results suggested that Be and Mn hamper the β1 austenite decomposition through the combination of defects from the phase and the atomic properties from these elements, such as atomic mass, atomic radius, and electronegativity. Similarity in crystalline structure and coordination number among Be, Mn, and the formed phases during heating also explain the success of these elements in the enhancement of Cu-Al shape memory alloys. The presence of Be and Mn also strengthened βʹ martensite through solid solution (interstitial and substitutional, respectively) and contributed to the phase boundaries formation at the intergranular region.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
