Yazar "Dispinar, Derya" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    Determination of effect of hydrogen on strength of aluminum by MD simulation
    (Springer Heidelberg, 2022) Tigli, Ahmet; Sahin, Hayati; Dizdar, Kerem Can; Dispinar, Derya
    The determination of types of defects that may be present in aluminum alloys has been a long-going discussion. Porosity has been held responsible for many of the failures in cast aluminum alloys. Due to the dramatic decrease in the solubility of hydrogen from liquid to solid aluminum, hydrogen is believed to be released from the solidification front and nucleate to form porosity. In this work, the diffusivity of hydrogen at different temperatures were investigated by means of Molecular Dynamic (MD) simulations. Dislocation density, crystal lattice deformation, and related changes in the tensile properties were determined in the presence of hydrogen for mono and nanocrystalline aluminum structures. The findings were correlated with the experimental and simulation data found in the literature where different tensile results were reported at different casting conditions.
  • [ X ]
    Öğe
    Water-aluminum reaction by MD simulations and its interpretation defect formation
    (Elsevier, 2023) Tigli, Ahmet; Dispinar, Derya
    Many of the aluminum and its alloys are produced by casting methods. During casting, aluminum is heated to temperatures above melting point. In the liquid state, aluminum reacts with water vapor to form aluminum oxide on the surface and hydrogen is dissolved in the melt. These are the two most critical defects that deteriorate the properties of the cast part. Therefore, it is important to investigate the possible reactions of water vapor with liquid aluminum in order to understand the formation of these defects. In this work, Molecular Dynamic (MD) analysis was used to evaluate the reactions of water vapor with aluminum at various temperatures (300, 500, 700, 900 and 1100 K). It was found that when aluminum reacts with water vapor, aluminum oxide layers form on the surface of the aluminum block. In addition, mono and di-atomic hydrogen are released due to the reaction between aluminum and water. These free hydrogen atoms are distributed homogeneously and rapidly in the aluminum block and gap between two aluminum blocks.