THE INVESTIGATION OF THE MECHANISM OF SUBSTRUCTURAL FORMATION IN REFRACTORY METALS AND THE RELATION TO THE OBSERVED MECHANICAL PROPERTIES. Period covered June 15, 1958 to June 15, 1959

The formation of substructure in molybdenum as a function of prestrain and polygonization anneal temperature has been demonstrated by metallographic and x-ray techniques. The x-ray-diffraction line width is markedly increased by the presence of substructure. In both polycrystalline and single crystal creep tests the creep resistance increased as a function of prestrain. In single crystal tests the creep resistance decreased with increased polygonization anneal time. (auth)