UBC Theses and Dissertations
High temperature creep deformation in solid solution alloys of lead Clark, Malcolm Arthur
Some high temperature creep properties of two alloy systems, Pb-Bi and Pb-In, have been studied. Three compositions in each system were used with all alloys being solid solutions at the deformation temperature. Solid solutions are usually divided into two groups, Class I and Class II, because of differences in certain creep properties. Attempts were made to classify the six alloys on the basis of the stress dependence of the steady state strain rate. Emphasis was also placed on the transient strain rate behaviour. Both initial transients from application of the load to attainment of steady state and transients in response to small increases or decreases in stress were studied as functions of stress, temperature and solute content. Significant differences were found in the shapes of the transients between the two alloy systems at some stresses and temperatures. These differences did not always coincide with the classification based on the steady state strain rate results. In Class I alloys, the glide of dislocations is usually considered as controlling the deformation, whereas in Class II dislocation climb is the recognized controlling mechanism. Two commonly accepted glide and recovery theories were evaluated for the present alloys but were found inadequate for some of the results. Two more recent theories of creep, the combined glide-recovery theory and the rearrangement theory, provided better theoretical characterizations for the two classes of alloy.
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