Analysis of Compositional Modification of Commercial Aluminum Bronzes to Obtain Functional Shape Memory Properties

Araújo, Aylanna Priscila Marques de; Simões, Jackson de Brito; Araújo, Carlos José de

doi:10.1590/1980-5373-mr-2016-1012

Cited by 8 publications

(5 citation statements)

References 10 publications

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“…Peaks belonging to the Cu9Al4 phase (i.e., (200), (421), (332), and (550) planes) were also present. The formation of α-Cu and Cu9Al4 phases is typically observed in Cu-Al-Ni systems [43,44]. The β phase in the Cu-Al-Ni system undergoes a eutectoid decomposition at ~840 K into α (Cu) and γ2 (Cu9Al4), then, the stable phases at room temperature are Cu and Cu9Al4.…”

Section: Resultsmentioning

confidence: 94%

Epitaxial Versus Polycrystalline Shape Memory Cu-Al-Ni Thin Films

et al. 2019

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In this work, two different approaches were followed to obtain Cu-Al-Ni thin films with shape memory potential. On the one hand, Cu-Ni/Al multilayers were grown by magnetron sputtering at room temperature. To promote diffusion and martensitic/austenitic phase transformation, the multilayers were subjected to subsequent heat treatment at 800 °C and quenched in iced water. On the other hand, Cu, Al, and Ni were co-sputtered onto heated MgO (001) substrates held at 700 °C. Energy-dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy analyses were carried out to study the resulting microstructures. In the former method, with the aim of tuning the thin film’s composition, and, consequently, the martensitic transformation temperature, the sputtering time and applied power were adjusted. Accordingly, martensitic Cu-14Al-4Ni (wt.%) and Cu-13Al-5Ni (wt.%) thin films and austenitic Cu-12Al-7Ni (wt.%) thin films were obtained. In the latter, in situ heating during film growth led to austenitic Cu-12Al-7Ni (wt.%) thin films with a (200) textured growth as a result of the epitaxial relationship MgO(001)[100]/Cu-Al-Ni(001)[110]. Resistance versus temperature measurements were carried out to investigate the shape memory behavior of the austenitic Cu-12Al-7Ni (wt.%) thin films produced from the two approaches. While no signs of martensitic transformation were detected in the quenched multilayered thin films, a trend that might be indicative of thermal hysteresis was encountered for the epitaxially grown thin films. In the present work, the differences in the crystallographic structure and the shape memory behavior of the Cu-Al-Ni thin films obtained by the two different preparation approaches are discussed.

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Section: Resultsmentioning

confidence: 94%

Epitaxial Versus Polycrystalline Shape Memory Cu-Al-Ni Thin Films

et al. 2019

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“…However, the phase transformation temperature is what mainly differentiates both alloys with smart properties. The austenitic transformation temperature range of NiTi varies between −50 • C and 110 • C [59,60] depending on the heat treatment and manufacturing method, however in copperbased alloys, it varies from −140 • C to 350 • C [9,59], from which pseudoelasticity can be obtained and also the SME for this last requires higher energy consumption.…”

Section: Comparison With Niti Specimens Produced By Laser Ammentioning

confidence: 99%

“…However, only a few authors have investigated its damping capacity and SMA properties. According to Marques de Araujo et al [9], this alloy would not have the property of pseudoelasticity nor the SME on its 'original' state. This is because the Ni and Fe addition alters the microstructure promoting the formation of intermediate phases that impair the stability and transformation of the martensitic phase, which is partially responsible for the shape memory properties [11].…”

Section: Introductionmentioning

confidence: 99%

“…However, it has been observed the presence of intermediate phases can interrupt the completed transformation. In other words, if samples have a mix of phases, the transformation occurs in those more susceptible to the stimulus, diminishing the total SMA response [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…This is because the Ni and Fe addition alters the microstructure promoting the formation of intermediate phases that impair the stability and transformation of the martensitic phase, which is partially responsible for the shape memory properties [11]. However, studies have shown that the SMA properties of the alloy could be improved by heat treatments of tempering [13] or Al addition [9].…”

Section: Introductionmentioning

confidence: 99%

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Applicability of LPBF for producing Cu-11Al-5Ni-4Fe wt.% with shape memory properties

Guerra

Ramos‐Grez

Fé-Perdomo

et al. 2023

Smart Mater. Struct.

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The Cu-11Al-5Ni-4Fe wt% alloy was consolidated by additive manufacturing (AM) to determine the method applicability for producing shape memory alloy. The alloy was researched through compressive stress in three conditions: commercial (cast), as-built, and as-built heat treated (quenched). The results demonstrated that the as-built sample acquired a reasonable superelasticity at room temperature (~4%), which was improved to 6% after quenching. The commercial sample damping capacity was better at high temperatures (350 °C) due to slip system activation at low stress (near 600 MPa), which resulted in a higher deformation energy dissipation. Due to the residual stress and null slip activation, the as-built samples showed low damping capacity and low permanent strain at any temperature; however, they showed greater degree of superelasticity. The AM technique of laser powder bed fabrication is concluded to be a viable option for producing printed parts with superelasticity and damping properties.

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