Date of Award
Doctor of Philosophy (PhD)
Jeffrey L. Evans
Emanuel A. Waddell
Viola L. Acoff
Grain boundaries., Metallography., Nickel.
Commercially pure nickel (Ni200) was thermo-mechanically processed to promote an increase in Σ 3 special grain boundaries and to induce segregation to the grain boundaries. Type-specific grain boundaries (special and random) were characterized using electron backscatter diffraction (EBSD) and the segregation behavior of elements and oxides at the atomic level as a function of grain-boundary character was studied using atom probe tomography (APT). Local electrode atom probe (LEAP) studies show enrichment of impurities in the random grain boundaries but not in special, Σ3, grain boundaries. The influence of anneal time on random grain boundaries was analyzed and showed clear evidence of increased concentration of segregants as annealing time is increased. The influence of anneal time on special, Σ3, grain boundaries was analyzed and showed clear evidence of decreased concentration of segregants as annealing time is increased.
Welsh, Shery, "Atomic scale study of the influence of grain boundary character on segregation and oxidation in commercially pure nickel" (2014). Dissertations. 51.