Enhancement of the diffusional creep of polycrystalline Al2O3 by simultaneous doping with manganese and titanium |
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Authors: | Yasuro Ikuma Ronald S Gordon |
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Affiliation: | (1) Department of Materials Science and Engineering, 84112 Salt Lake City, Utah, USA |
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Abstract: | The effect of simultaneous doping with manganese and titanium on diffusional creep was studied in dense, polycrystalline alumina over a range of grain sizes (4–80 m) and temperatures (1175–1250° C). At a total dopant concentration of 0.32–0.37 cation %, diffusional creep rates were enhanced considerably such that the temperature at which cation mass transport was significant was suppressed by at least 200° C compared to that observed in undoped material. The Mn-Ti (and Cu-Ti) dopant couple was far more effective in enhancing creep rates and suppressing sintering temperatures than the Fe-Ti couple. The enhanced mass transport kinetics are believed to be caused by significant increases in both aluminium lattice and grain-boundary diffusion. When aluminium grain-boundary diffusion is enhanced by increasing the concentration of divalent impurity (Mn2+, Fe2+) or by creep testing at low temperatures, creep deformation is Newtonian viscous. |
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