s 70th birthdayThe effective resistivity is calculated for a simple cell structure by means of the Boltzmann equation. I n less heavily deformed metals the cell structure has only a negligible effect on the residual resistivity. In heavily deformed metals the observed DMR is in the same order of magnitude as that arising from the presence of the cell structure. Oleo decreases with increasing amount of cold work and this experimental result suggests that the DMR arising from the anisotropic dislocation scattering is larger than the DMR due to the cell structure.Wt Hilfe der Boltzmann-Gleichung wird der spezifische Widerstand einer einfachen Zellstruktur bestimmt. I n maRig verformten Metallen ist der EinfluR der Zellstruktur auf den Restwiderstand zu vernachlassigen. I n stark verformten Metallen liegt die Abweichung von der M E in derselben GroBenordnung, wie sie der inhomogenen Versetzungsverteilung entspricht. A/@, nimmt mit zunehmender Verformung ab, woraus geschlulfolgert wird, daR die Abweichung, die von der Anisotropie der Versetzungsstreuung stammt, groBer ist als die, die von der Zellstruktur hervorgerufen wird.

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Segregation and solution of iron is followed up on a commercial WFe dilute alloy by measuring electrical resistivity, thermopower and — on the fracture surface — AES. The thermopower measures practically only the solute iron concentration in this alloy. At the same time the excess electrical resistivity is sensitive mostly to the concentration of grain boundaries and the AES measures the iron accumulated on the surface of the grain boundaries. According to these measurements grain boundary segregation occurs at temperatures where the bulk diffusion is negligible yet. So this segregation can be explained only by moving grain boundaries, which “sweep over” the crystallites, accumulating the iron atoms. It turned out that only a part of the iron segregated onto the grain boundaries, the larger part segregated onto the second phases, although their total surface is about ten times less. Supposing a state close to the equilibrium, the heats of segregation is estimated to be 50 and 100 to 120 kJ/mol for segregation to grain boundaries and to second phases, respectively.