The structural, elastic and electronic properties of Cu-X compounds in the Cu-X(X =Al, Be, Mg, Sn, Zn and Zr) systems were predicted systematically by first-principles calculations. The ground state properties such as lattice constant, bulk modulus(B)and it's pressure derivative(B') were predicted by fitting a four-parameter Birch–Murnaghan equation and the elastic constants(cij′s)are determined by an efficient strain-stress method. The calculated lattice parameters and cij′s of these binary compounds agree well with the available experimental data in the literature. In addition, elastic properties of polycrystalline aggregates including bulk modulus(B), shear modulus(G), elastic modulus(E), B/G(bulk/shear) ratio, and anisotropy ratio(AU) are calculated and compared with the experimental and theoretical results available in the literature. Based on electronic density of states(DOS) analysis, it can be revealed that all the compounds in the present work are metallic in nature.
A solid state synthesis of ultrafine/nanocrystalline WC-10Co composite powders was reported from WO3 , Co3O4 and carbon powders after reduction and carburization at relatively low temperatures in a short time under pure H2 atmosphere. The effects of ball milling time and reaction temperature on the preparation of ultrafine/nanocrystalline WC-Co composite powders were studied using X-ray diffraction and scanning electron microscope (SEM). The results show that fine mixed oxide powders (WO3 , Co3O4 and carbon powders) can be obtained by long time ball milling. Increasing the reaction temperature can decrease the formation of Co3W3C and graphite phases and increase the WC crystallite size. Long-time ball milling and high reaction temperature are favorable to obtain fine and pure composite powders consisting of nanocrystalline WC from WO3 , Co3O4 and carbon powders.
