CYCLE DEPENDENT DEFORMATION BEHAVIOR OF CLOSEPACKED METALS.
Rept. for 1 Apr 61-July 63,
ILLINOIS UNIV URBANA
Pagination or Media Count:
Deormation effects associated with combined creep and fatigue loading are investigated for several metals over a range of homologous temperatures. Three fundamentally different but related sets of experiments are included. The phenomenon of cyclic stress induced creep is investigated for copper, aluminum and cadmium at room temperature and 78K. For combined creep and fatigue, a clear delineation is established between deformation processes which are timedependent and those which are cycle-dependent. Transmission electron microscopy is used to study the dislocation arrangements formed in aluminum at 78K by the action of repeated tensile stresses. Finally a study is made of the low temperature yield point effect in fcc metals and its enhancement by cyclic straining. Combined with an interpretation and critical analysis of the current experimental and theoretical situation, the results and conclusions of the three experimental programs are used to define the necessary constituents of dislocation models which are applicable to cycle-dependent deformation problems. Author