The Experts below are selected from a list of 2235 Experts worldwide ranked by ideXlab platform

I V Shvets - One of the best experts on this subject based on the ideXlab platform.

Baptiste Gault - One of the best experts on this subject based on the ideXlab platform.

  • chemical segregation and precipitation at anti phase Boundaries in thermoelectric heusler fe2val
    Scripta Materialia, 2020
    Co-Authors: Leonie Gomell, Shyam Katnagallu, Abou Diackrasselio, Stefan A Maier, Loic Perriere, Christina Scheu, Eric Alleno, Baptiste Gault
    Abstract:

    Abstract Fe2VAl exhibits promising properties for thermoelectric applications. Here, we investigated the microstructure of melt spun Fe2VAl using electron microscopy, atom probe tomography and field ion microscopy. We observe platelet-shaped VCxNy precipitates in the vicinity of Antiphase Boundaries (APB) oriented along the {100}-plane. The mean distance between these precipitates is (140 ± 40) nm. This distance is shorter than the mean free phonon path at room temperature in Fe2VAl. Thus, these VCxNy precipitates, combined with the APB may efficiently lower the thermal conductivity of the alloy.

Minoru Umemoto - One of the best experts on this subject based on the ideXlab platform.

  • martensitic stabilization and defects induced by deformation in tini shape memory alloys
    International Journal of Minerals Metallurgy and Materials, 2011
    Co-Authors: Shuai Wang, Koichi Tsuchiya, Lei Wang, Minoru Umemoto
    Abstract:

    Martensitic stabilization caused by deformation in a TiNi shape memory alloy was studied. Special attention was paid to the deformed microstructures to identify the cause of martensitic stabilization. Martensitic stabilization was demonstrated by differential scanning calorimetry for the tensioned TiNi shape memory alloy. Transmission electron microscopy revealed that Antiphase Boundaries were formed because of the fourfold dissociation of [110]B19’ super lattice dislocations and were preserved after reverse transformation due to the lattice correspondence. Martensitic stabilization was attributed to dislocations induced by deformation, which reduced the ordering degree of the microstructure, spoiled the reverse path from martensite to parent phase compared with thermoelastic transformation, and imposed resistance on phase transformation through the stress field.

  • deformation mechanism and stabilization of martensite in tini shape memory alloy
    Journal of Materials Science & Technology, 2010
    Co-Authors: Shuai Wang, Koichi Tsuchiya, Lei Wang, Minoru Umemoto
    Abstract:

    The deformed microstructures of a TiNi shape memory alloy were investigated in present study to clarify the deformation mechanism. It is found that the stress-strain curve was divided into three stages based on the deformation modes. The cause of martensitic stabilization effect was also interpreted by paying special attention to the deformed microstructures. Transmission electron microscopic examination revealed that at the early stage of deformation martensitic reorientation and compound twinning relieved some of the elastic strain energy stored in martensite, and this contributes to the martensitic stabilization effect. However, when deformation strain became larger, the density of dislocations increased correspondingly. Antiphase Boundaries were also found. The degree of ordering was therefore decreased due to dislocations and Antiphase Boundaries. So disordering was another cause of martensitic stabilization effect. In the middle stage of deformation martensitic stabilization was attributed to the two reasons above.

Sunil K Arora - One of the best experts on this subject based on the ideXlab platform.

J P Srivastava - One of the best experts on this subject based on the ideXlab platform.

  • influence of Antiphase boundary density on the conduction noise properties of epitaxial magnetite thin films
    Journal of Applied Physics, 2005
    Co-Authors: Sunil K Arora, I V Shvets, R G S Sofin, Ravi Kumar, Wasi M Khan, J P Srivastava
    Abstract:

    Low frequency conduction noise (1∕f noise) properties of epitaxial magnetite (Fe3O4) thin films having a varying density of Antiphase Boundaries (APBs) were investigated as a function of temperature and frequency. Temperature dependence of noise exhibits a similar behavior to that of resistivity for all the films. The magnitude of normalized noise (Sv∕V2) decreases with the increasing film thickness, which correlates well with the density of APBs. The quantitative feature of noise, i.e., Hooge parameter has a strong thickness dependence at low temperatures which implies that the APBs play an important role in determining the transport mechanism in epitaxial Fe3O4 films.