UBC Theses and Dissertations
Some aspects of the yielding and flow of lithium fluoride Martinson, Riho Hans
Tension tests have been performed on LiF single crystals. The results of strain rate change tests are not wholly consistent with current theories of deformation processes. The number of mobile dislocations appears to depend sensitively on the stress prevailing during straining. A short investigation of the effect of removing surface layers during deformation was undertaken. The surfaces of chemically polished LiF single crystals are not sites of strong work-hardening. The effects of magnesium-rich surface layers on the mechanical properties of LiF have been studied. The yield stress, critical tensile stress, and work-hardening slope increase linearly with layer thickness, while the strain to fracture decreases rapidly with increasing layer thickness. The results of tension tests, supplemented by metallographic evidence, indicate that the yield stress and the critical tensile stress are not determined by surface source operation.
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