Investigation of thermodynamic and microstructural characteristics of NiTiCu shape memory alloys produced by arc-melting method

Tatar, Cengiz; Acar, Rauf; Qader, İbrahim Nazem

doi:10.1140/epjp/s13360-020-00288-w

Cited by 41 publications

(13 citation statements)

References 35 publications

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“…Entropy is another physical parameter that can change throughout a thermodynamic process. The entropy change in an austenite transformation process (∆ → ) can be calculated by the following formula [3,[29][30][31]:…”

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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“…Materials with pure elements have particular properties, which may not be used for all applications, thus alloying with different amounts of other elements can give novel features to the materials. SMAs are also can obtain new characteristics by alloying with different elements [62,22]. Khalil-Allaf et al [63] studied the different composition of NiTi alloy.…”

Section: Changing Compositionsmentioning

confidence: 99%

The Effect of Different Parameters on Shape Memory Alloys

Qader

Kök

Dağdelen

et al. 2020

Sakarya University Journal of Science

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Shape memory alloys' characteristics are different from ordinary materials because they can memorize their predetermined shape, thus they are excellent candidates for different applications. In this review article, the most interesting parameters that researchers are using in their investigation have been highlighted. Also, the popular techniques used for the characterization of shape memory alloys have been described. The diagrams and sketches can show a clear view of metallurgies and related research areas.

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“…In particular, extremely high damping was found for compositions with Cu content higher than 15 at.% and particularly good results are obtained for NiTiCu20% [ 28 , 29 , 30 , 31 ]. Unfortunately, this high content of Cu suppresses the workability of the alloy, principally by the formation of secondary phases, and segregates [ 32 ]. The as-cast material is therefore investigated in the present study and different types of microstructures obtained after several thermal treatments are highlighted for this particular composition.…”

Section: Introductionmentioning

confidence: 99%

Microstructural and Thermo-Mechanical Characterization of Cast NiTiCu20 Shape Memory Alloy

et al. 2021

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Among NiTi-based alloys, one of the most promising and exploited alloys is NiTiCu, since the addition of Cu in substitution of Ni in the binary equiatomic NiTi has a significant influence on the martensitic transformation and the thermomechanical properties of the system. A high content of Cu improves the damping properties at the expense of phase homogeneity and workability. The present study focuses on an alloy with a high copper content, i.e., 20 at.%. For this specific composition, the correlation between the thermal treatments, microstructure, formation of secondary phases, and damping properties are investigated by several analyses. The microscopic observation, together with the compositional analysis, allowed the determination of four different phases in the alloy. Both the calorimetry and dynamic thermo mechanical measurements, which confirmed the high damping ability of the alloy, provided a characterization of the martensitic transition. Finally, the electron backscatter diffraction (EBSD) analysis detected the different crystallographic structures (i.e., cubic austenite, orthorhombic martensite, and cubic (face-centered) NiTi2) and their orientation in the different phases. Therefore, the present work aims to improve the knowledge of the role of secondary phases in the optimization of the NiTiCu20 alloy as a valuable alternative to typical alloys used for damping purposes.

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Investigation of thermodynamic and microstructural characteristics of NiTiCu shape memory alloys produced by arc-melting method

Cited by 41 publications

References 35 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

The Effect of Different Parameters on Shape Memory Alloys

Microstructural and Thermo-Mechanical Characterization of Cast NiTiCu20 Shape Memory Alloy

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