Now showing 1 - 2 of 2
  • Placeholder Image
    Publication
    First-Principles Investigations into the Electrochemical Behavior of Mg-Based Intermetallics
    (01-01-2023)
    Mishra, Pragyandipta
    ;
    Kumar, Pranav
    ;
    ;
    Magnesium alloys have drawn considerable attention for several engineering applications, owing to their excellent properties like low density and high specific strength. The room temperature ductility and mechanical properties of Mg are usually enhanced by alloying additions. Based on the thermomechanical processing, the presence of critical concentration of alloying element typically leads to the formation of stable binary intermetallic phases with Mg, thereby distinctly altering the microscopic electrochemical properties of the alloy. However, the secondary intermetallic phases in Mg alloys are typically of sub-micron size; thus, accurate electrochemical characterization is a challenging issue. Using first-principles calculations, the electrochemical behavior of various Mg intermetallics was comprehensively quantified. The electrochemical polarization behavior of the intermetallics was strongly dependent on surface-mediated properties and chemical bonding characteristics. Finally, the computational framework provides an accurate screening tool that can assist in alloy design and development of coatings.
  • Placeholder Image
    Publication
    First-Principles Investigation of the Effect of Solutes on the Ideal Shear Resistance and Electronic Properties of Magnesium
    (01-01-2019)
    Garg, P.
    ;
    ;
    Solanki, K. N.
    Solute addition is an effective way to enhance mechanical properties, especially in magnesium based alloys due to the limited number of slip systems available for deformation at the room temperature. Hence, the effects of various alloying elements on ideal shear resistance (ISR) across different slip systems of Mg were investigated using first-principles calculations. The addition of a Ce, Y, or Zr solute atom was found to decrease ISR, whereas the substitution of a Sn, Li, Al, or Zn atom increased the ISR of Mg. The most active slip system in Mg changed from the basal partial (0001) to prismatic upon substitution of a Ce, Y, or Zr solute atom, whereas the addition of Sn, Li, Al, or Zn solute atom had negligible effect on the plastic anisotropy. Furthermore, the electronic density of states and valence charge transfer provides a quantum insight into the underlying factors influencing the observed softening/strengthening behavior. For instance, the electronic density of states calculation shows that the contribution from d states of Ce, Y, and Zr solute atoms decreases the electronic structure stability of their respective solid solution, thereby enhancing slip activities. Theoretical analyses were also performed, and a shearability parameter was introduced to understand the implications of the observed variation in ideal shear resistance on the macroscopic behavior of Mg alloys.