Influence of aluminium and iron contents on the transformation temperatures of Cu-Al-Fe shape memory alloys

Raju, T. N.; Sampath, V.

doi:10.1007/s12666-011-0032-6

Cited by 30 publications

(10 citation statements)

References 11 publications

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“…Yang et al [7] worked on Cu84-ϰ Al11+ϰ Fe5 SMAs for three samples with (ϰ = 0, 1, 2), and they realized that the transformation temperatures were decreased with increasing Al content. Likewise, Raju and Sampath [18] Reported that a small change of Fe in the CuAlFe SMA caused a serious change in the transformation temperatures. The results of this study agree with the aforementioned studies, whereby, increased Fe-content in CuAlFe alloy caused a significant shift in the transformation temperature, e.g., Mp dropped from 252.6 to 187.5 o C.…”

Section: Resultsmentioning

confidence: 99%

Quaternary Element Incorporation Effects on Thermal Properties and Crystal-Micro Structure of Cu-Al-Fe High Temperature Shape Memory Alloys

Balci

Akpınar

2021

International Journal of Thermodynamics

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Recently, researchers have shown an increased interest in Cu-based shape memory alloys due to their special characteristics, which can be used in high-temperature applications. In this study, ternary shape memory alloys in the form of CuAlFe with different ratios of iron and quaternary CuAlFe alloys containing Ni, Mn, and Ti were produced by arc melting. Then the produced alloys were kept at 900 ℃ for 24 hours to make sure that all constituents in the alloys were homogeneously distributed. The change in the transformation temperatures for all samples was checked out by Differential Scanning Calorimetry (DSC). Also, the change in the crystal structure and microstructure were determined by x-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. The aim of this study is to compare the thermal and microstructural properties of quaternary alloys formed by adding Ni, Mn, and Ti elements to CuAlFe-based shape memory alloy with different rates, which is not available in the literature. The result of this study; although the electron concentration value increased, a significant decrease was observed in the values of the transformation temperatures. Increasing Fe-element decreased the transformation temperature non-linearly. Ni and Mn contents added to CuAlFe shape memory alloys have reduced transformation temperatures, such as Af and Mf. The XRD and SEM-EDX measurements showed the martensite phase with some produced compound precipitated in the matrix phase.

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Section: Resultsmentioning

confidence: 99%

Quaternary Element Incorporation Effects on Thermal Properties and Crystal-Micro Structure of Cu-Al-Fe High Temperature Shape Memory Alloys

Balci

Akpınar

2021

International Journal of Thermodynamics

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“…The calculated e v /a and c v values on experimentally determined austenite-martensite and martensite-austenite transformation temperatures of ternary, quaternary and quinary Cu-based SMAs based on the work [20,21] of one of the authors (V Sampath) of the paper and other researchers are given in tables 1-3.…”

Section: Resultsmentioning

confidence: 99%

Experimental and theoretical analyses of transformation temperatures of Cu-based shape memory alloys

Sampath¹,

Gayathri

Srinithi³

2019

Bull Mater Sci

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Binary-shape memory alloys that are based on copper, mainly copper-aluminium, copper-zinc and copper-tin alloys, either with or without ternary elemental additions, are of special interest to the industry and academia because of their good shape recovery, ease of processing, larger recovery strain and lower cost. However, unlike Ni-Ti shape memory alloys, their uses are moderately limited due to shortcomings, such as stabilization of martensite due to ageing, brittleness and low mechanical strength. Therefore, efforts have been made over the years to overcome these limitations using appropriate ternary and quaternary elemental additions. This work takes into account the data obtained from the experimental work carried out by the authors of this paper as well as the data obtained from the experimental and theoretical works carried out by earlier researchers in this area that have been published in the literature over the years. It is observed in quaternary shape memory alloys based on copper that with an increase in the atomic radius of the quaternary element, the hysteresis width is found to increase. With the addition of ternary elements to binary Cu-based alloys (Cu-Al and Cu-Zn), and quaternary elements to ternary Cu-based alloys (Cu-Al-Fe, Cu-Al-Ni, Cu-Al-Mn, Cu-Zn-Al, Cu-Zn-Ni and Cu-Zn-Si), the M s temperature either increases or decreases. This influence is directly correlated with the e v /a ratio and c v values. It is also observed that as the concentration of electrons decreases, the M s temperature decreases too. In addition, in this paper, we have tried to obtain relationships between the M s temperature and the mass or atomic% of different elements through multiple regressions to generalize the interpretations.

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“…The experimental heat treatment included quench and recovery heat treatment after the deformation. The quenching process was 950 °C× 2h→850 °C× 15 min→water quenching [27], as shown in figure 3. Under normal conditions, the heat treatment process of shape memory recovery after deformation was to heat up to the temperature of A f +50 °C at a heating rate of 15 °C min −1 for 10 min.…”

Section: Heat Treatment Processmentioning

confidence: 99%

Microstructure and shape memory properties of Cu-Al-Fe alloys with different Al contents made by additive manufacturing technology

Wang

Huang

Shen

et al. 2022

Mater. Res. Express

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The Al contents play an exceedingly important role in Cu-Al system shape memory alloys (SMAs), and Cu-Al-Fe alloy represents the new development directions of Cu-Al system SMAs. The Cu-xAl-4Fe (x=11, 13, 15 wt.%) alloys, which take the powder core wire with a structure resistant to element burning as additive manufacturing materials, were prepared by arc melt deposition process. In this work, the as-deposited, quenched and deformed microstructure was studied in detail by utilizing OM, SEM, and XRD. The shape memory properties of the alloys were analyzed by the bending tests. The effect mechanism of the Al content on the shape memory properties of Cu-Al-Fe alloys was also investigated. Results show that the as-deposited microstructure presents sub-eutectic to hyper-eutectic characteristics with the rise in Al content. After quenching, the microstructure of 11 wt.% Al, 13 wt.% Al, and 15 wt.% Al alloys are the α' martensite, the β1' martensite, and the β1 austenite with high order degrees. Under 4% pre-strain, the shape memory recovery rate of the 13 and 15 wt.% Al alloy is 100%, but the shape memory recovery rate of 11 wt.% Al alloy is only 22.6%. However, compared with the ductility of 11 and 13 wt.% Al alloy, that of 15 wt.% Al alloy is poor, which causes failure to withstand 4% bending pre-strain. After bending deformation, cracks of 15 wt.% Al alloy along the crystals appear and cause the memory strip to break. The analysis indicates that the properties of Cu-Al-Fe alloy have an intense sensitivity to the Al element. The martensitic order degree of the alloy is elevated with the increase in the Al content, and the grain interface gradually becomes sharper. Solidification impurities are formed at the grain boundary during the additive manufacturing process due to the influence of the interface energy. At the same time, the invading O2 combines with the more active Al element to form metal oxidation, which markedly reduces the grain boundary strength and the bending strength of the alloy. As a result, the shape memory properties cannot be reflected in the case of high Al content.

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Influence of aluminium and iron contents on the transformation temperatures of Cu-Al-Fe shape memory alloys

Cited by 30 publications

References 11 publications

Quaternary Element Incorporation Effects on Thermal Properties and Crystal-Micro Structure of Cu-Al-Fe High Temperature Shape Memory Alloys

Quaternary Element Incorporation Effects on Thermal Properties and Crystal-Micro Structure of Cu-Al-Fe High Temperature Shape Memory Alloys

Experimental and theoretical analyses of transformation temperatures of Cu-based shape memory alloys

Microstructure and shape memory properties of Cu-Al-Fe alloys with different Al contents made by additive manufacturing technology

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