The effects of cobalt elements addition on Ti2Ni phases, thermodynamics parameters, crystal structure and transformation temperature of NiTi shape memory alloys

Kök, Mediha; Zardawi, Hanaa Shahab Ahmed; Qader, İbrahim Nazem; Kanca, Muhammed Sait

doi:10.1140/epjp/i2019-12570-9

Cited by 42 publications

(15 citation statements)

References 24 publications

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“…The enthalpy is changed during martensitic phase transformation in an SMA [34]. Besides, Gibbs free energy for the martensite phase transformation is as follows [35][36][37]:…”

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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“…The enthalpy is changed during martensitic phase transformation in an SMA [34]. Besides, Gibbs free energy for the martensite phase transformation is as follows [35][36][37]:…”

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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“…where T o is defined as the equilibrium temperature when Gibbs free energy (DG) in both forward and reverse phase transformation are equal to zero. The value of T o has proposed such that [19,20]:…”

Section: Resultsmentioning

confidence: 99%

Thermal stability and some thermodynamics analysis of heat treated quaternary CuAlNiTa shape memory alloy

Kök

Qader

Mohammed

et al. 2019

Mater. Res. Express

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This study presents the heat treatment effect on a quaternary Cu 79 Al 13 Ni 4 Ta 4 (wt%) shape memory alloy. The induction technique was used for melting the alloy and then four pieces of the alloy were heat-treated at (673 K, 873 K, 1073 K, and 1273 K) for one hour. Some physical parameters were characterized using DSC, XRD, and SEM-EDX. The as-cast and heat-treated samples were studied in terms of phase transformation temperatures, enthalpy change, entropy change, Gibbs free energy, and elastic energy. The transformation temperature was increased by applying heat treatment. Martensitic phase transformation at heat treatment temperature of 1273 K was not observed. Besides, after rising heat treatment temperature, some new phases such as ¡ b ¢ ¢ and 1 1 were specified in XRD patterns and SEM images. Generally, for heat-treated samples, the transformation temperature remains almost constant after the 3rd cycle. However, the thermal stability of the as-cast alloy was not affected through thermal cycling.

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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 phase transformation temperatures are austenite start, austenite finish, martensite start, martensite finish and martensite transformation temperature by deformation (i.e. maximum temperature at which martensite transformation occurs) Temperatures that are symbolized as As, Af, Ms, Mf, and Md, respectively [17][18][19][20][21][22][23][24][25][26][27][28][29].…”

Section: Shape Memory Alloysmentioning

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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The effects of cobalt elements addition on Ti2Ni phases, thermodynamics parameters, crystal structure and transformation temperature of NiTi shape memory alloys

Cited by 42 publications

References 24 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

Thermal stability and some thermodynamics analysis of heat treated quaternary CuAlNiTa shape memory alloy

The Effect of Different Parameters on Shape Memory Alloys

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