Yazar "Ozkul, Iskender" seçeneğine göre listele

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    Öğe
    Effect of Cu, Sn and Sb addition on the structural, thermal and magnetic properties of body-centered cubic structured CoNiMnGaSi high entropy alloy
    (Springer Heidelberg, 2022) Simsek, Telem; Ozkul, Iskender; Canbay, Canan Aksu; Avar, Baris; Simsek, Tuncay; Guler, Seval Hale; Ozcan, Sadan
    In this study structural, morphological, thermal and magnetic properties of equiatomic CoNiMnGaSi (base), CoNiMnGaSiCu, CoNiMnGaSiSn and CoNiMnGaSiSb alloys are discussed. The formation of solid-solution nanocrystalline bcc structure of the alloys was determined by XRD and DTA techniques. SEM-EDS analyses also revealed the homogeneous distribution of the elements. The room temperature magnetic hysteresis loops showed that as-casted alloys reached saturation easily with coercivity less than or equal to 35 Oe. As the Cu and Sn were added to the alloy, the saturation magnetization was decreased from 112 emu/g to 50 emu/g, which was mainly due to the substitution of non-magnetic atoms to the magnetic Co in the base CoNiMnGaSi alloy, whereas the addition of Sb to the base alloy did not have a significant effect on the M-s. The CoNiMnGaSiSb was found to have the highest Curie Temperature of 670 K, which makes the alloy a promising candidate for power industry-related applications.
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    Öğe
    Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy
    (Springer Heidelberg, 2022) Ozkul, Iskender; Karaduman, Oktay; Simsek, Telem; Simsek, Tuncay; Canbay, Canan Aksu; Ibrahim, Pshdar Ahmed; Arpa, Ipek A. K.
    To discover cheaper and functional species of shape memory alloys (SMAs) is one of the main objectives for interested researchers. In this work, five different alloys were produced by adding different quaternary alloying elements (Ti, Ga, V, Hf, and Nb) into the ternary CuAlNi-base (C-) alloy.The thermal and structural properties of the produced alloys were investigated. The phases of Al7Cu23Ni, AlNi, CuNi2Ti, Al80V20, AlNbNi2, Cu3Ga, and NiSHf were observed by X-ray powder diffraction (XRD) analyses after arc melting processes. The average crystallite sizes of the produced alloys were calculated as 17.1, 18.9, 19.4, 20.8, and 23.7 nm for CV, CNb, CHf, CTi, and CGa alloys, respectively. The highest lattice strain was found at about % 0.572 for CGa alloy. Measuring the magnetic properties of the produced alloys revealed the paramagnetic behavior of the alloys at room temperature.
  • [ X ]
    Öğe
    Experimental investigation of the effects of different quaternary elements (Ti, V, Nb, Ga, and Hf) on the thermal and magnetic properties of CuAlNi shape memory alloy (Jun, 10.1557/s43578-022-00625-y, 2022)
    (Springer Heidelberg, 2022) Ozkul, Iskender; Karaduman, Oktay; Simsek, Telem; Simsek, Tuncay; Canbay, Canan Aksu; Ibrahim, Pshdar Ahmed; Arpa, Ipek Ak
    [Abstract No tAvailable]
  • [ X ]
    Öğe
    Investigation of shape memory characteristics and production of HfZrTiFeMnSi high entropy alloy by mechanical alloying method
    (Elsevier, 2022) Guler, Omer; Simsek, Tuncay; Ozkul, Iskender; Avar, Baris; Canbay, Canan A.; Chattopadhyay, Arun K.; Guler, Seval H.
    High entropy alloy (HEA) with shape memory effect (SME) has been the subject of great interest for the past few decades. However, with the increased demands for new materials for high thermal applications, the research activities on the multi elemental high entropy shape memory alloys (HESMA) have been increased by many folds recently. The nano crystalline HEA powder with shape memory effect developed in this study, HfZrTiFeMnSi, was produced by mechanical alloying (MA) for the first time. In this method equiatomic ratio of Hf, Zr, Ti, Fe, Mn, and Si were mixed together and milled by MA process for 100 h. The powder formed was of amorphous in nature. Elemental mapping of the powder from SEM-EDS revealed homogeneity of the alloying elements confirming successful fabrication of HfZrTiFeMnSi HEA powder. The DSC studies from ambient to 500 degrees C of the annealed alloy powders showed reversible austenitic to martensitic (A <-> M) transformations. The A <-> M transformation hysteresis seemed to vary with the milling time and annealing temperature. The enthalpy values, Delta H, for the transformation were calculated from the DSC plots using tangent method for peak area calculation. Regardless of the annealing temperature, the thermal analysis revealed that the Delta H, equilibrium temperature (T0), and crystallization temperature values decreased with the increasing milling time.