ISSN:
1432-0630
Keywords:
66.30Jt
;
61.80J
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract Volume and grain boundary diffusion of 113Sn in aluminium was investigated with the radiotracer method. The implantation technique was used for tracer deposition to avoid problems of tracer hold-up caused by the oxide layer always present on aluminium. The diffusion penetration was chosen large enough to permit serial sectioning of samples with the aid of a microtome. The temperature dependence of the volume diffusivity was determined as D(T)=4.54×10−5×exp[−(114.5±1.2)kJmol−1/RT] m 2 s −1. This confirms previous measurements from our group which already showed that Sn is the fastest foreign metal diffusor so far investigated in aluminium. Grain boundary diffusion of 113Sn in Al polycrystals was measured in the type-B kinetic regime. The grain boundary diffusion product P=sδD gb (s=segregation factor, δ=grain boundary width, D gb=grain boundary diffusivity) was found to be strongly affected by the impurity content of aluminium. For Al polycrystals of 99.9992% nominal purity we obtained P 5N(T)=1.08×10−8exp [−(96.9±7.5) kJ mol−1/RT] m3 s−1 and for less pure Al polycrystals of 99.99% nominal purity P 4N(T)=3.0×10−10 exp [−(90.1±4.2) kJ mol−1/RT] m3 s−1 was determined. The grain boundary diffusion product in the purer material is more than one order of magnitude higher than in the less pure material. Very likely this is an effect of co-segregation of non-diffusant impurities into the grain boundaries.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00357191
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