The lattice dynamic of some binary and quaternary alloys

THE LATTICE DYNAMIC OF SOME BINARY AND QUATERNARY ALLOYS (Ph. D. Thesis) Mustafa ÖZDURAN GAZİ UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY January 2004 ABSTRACT In this work, the lattice dynamic of some binary and quaternary alloys are studied. The parameters defining the MBP for the examined binary [Ni(i_X) - Crx (x=0.196), Co(i.x)-Nix (x=0.50, 0.32, 0.25, 0.10)] and quaternary (Fe-18%Cr- 10%Mn-16%Ni, Fe-18%Cr-12%Ni-2%Mo) alloys have been computed following the method defined by Akgün and Uğur (1, 2). The phonon frequencies of the alloys along the principal symmetry directions have been computed using the calculated two-and three-body force constants. Some elastic properties of the alloys; such quantities as the second-order (Cn, Cn, C44) and third-order (Cm, Cm-Cm, Cns=Cu*) elastic constants, the thermal expansion coefficient (at), the pressure derivatives of the bulk modulus (B) and second- order clastic constants (dB\ dCtJ ve dP J-i dp the Young's modulus (E), the anisotropy multiplier (A), and the shear modulus (G) have been computed using the crystal model defined by Akgün (3). Science code Key words Page number Adviser 404.05.01 Elastic constants, phonon frequencies, force constants 71 Prof. Dr. İrfan AKGÜN