KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Subject: search.filters.subject.Elastic constant

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    A first principles investigation on the structural, elastic, and mechanical properties of MAX phase M3AlC2 (M= Ta, Ti, V) as a function of pressure
    (2022-03-01)
    Sailuam, Wutthigrai
    ;
    Fongkaew, Ittipon
    ;
    Limpijumnong, Sukit
    ;
    Phacheerak, Kanoknan
    This study investigated the structural, elastic, and mechanical properties of hexagonal M<inf>3</inf>AlC<inf>2</inf> (M = Ta, Ti, and V) within MAX phases by first-principles calculations. The considered properties of M<inf>3</inf>AlC<inf>2</inf> (M = Ta, Ti, and V) compounds at 0 GPa were in reasonable agreement with available experimental and other theoretical data. The elastic stability shows that no structural phase transition occurred in pressure up to 20 GPa for all compounds. The resistances to linear compression were more forceful than the resistances to compression in shape. The bulk modulus, shear modulus, and Young's modulus for M<inf>3</inf>AlC<inf>2</inf> (M = Ta, Ti, and V) compounds follow the order Ta<inf>3</inf>AlC<inf>2</inf> > V<inf>3</inf>AlC<inf>2</inf> > Ti<inf>3</inf>AlC<inf>2</inf>. The Bader charge analysis result shows the increasing of covalence bond in their structure after the pressure increased. Furthermore, Pugh's criterion B/G and Poisson's ratio v confirmed that the M<inf>3</inf>AlC<inf>2</inf> (M = Ta, Ti, and V) compounds had intrinsic brittleness. The sound velocity and Debye temperature of all compounds increased with pressure increasing. The bond stiffness and the shear anisotropy affected by pressure were reported and discussed.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Elastic and mechanical properties of hydroxyapatite under pressure: A first-principles investigation
    (2020-09-01)
    Sailuam, Wutthigrai
    ;
    Phacheerak, Kanoknan
    ;
    Atipong bootchanont
    ;
    Fongkaew, Ittipon
    ;
    Limpijumnong, Sukit
    The structural, elastic, and mechanical properties of hydroxyapatite (HAp) were investigated by generalized gradient approximation (GGA) in the functional form by Perdew, Bruke, and Ernzerhof (PBE) exchange-correlation functional using density-functional theory. Our calculated equilibrium lattice parameters at ambient pressure are in good agreement with the experimental and previous theoretical results. The details of the structural, mechanical, and electrical properties such as elastic constants, bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratioν, Cauchy pressure, shear anisotropic factor A, and total density of states under pressure ranging 0 GPa to 10 GPa are studied. The lattice parameters a and c are found to be decreased with increasing pressure. Moreover, the lattice parameter a is more sensitive to external pressure than c. The calculated elastic constants of hexagonal HAp increase with increasing pressure. The elastic constants C<inf>11</inf> and C<inf>33,</inf> which represent the elasticity in length are larger than the elasticity in shape, which represent by the elastic constants C<inf>12</inf>, C<inf>13</inf>, C<inf>44</inf>, and C<inf>66</inf>. The deformation resistances along the axial direction are stronger than the deformation resistances in shape. The calculated B/G, Poisson's ratio ν, and Cauchy pressure show that the hexagonal HAp behaves as a ductility material at ambient pressure and has more ductile under pressure. While the calculated shear anisotropic factor A indicate that the HAp shows elastic anisotropy under pressure. Moreover, calculated total density of states (DOS) show that HAp becomes more insulator property with increasing pressure.