It is shown that in polycrystalline Al samples, having subgrain and large-angle boundaries, the grain boundary part of the penetration plots (1n I Approximately y**6**/**5) determined by sectioning can be decomposed into two regions. The time dependence of the slopes of both segments can be described well with the Whipple's solution of the diffusion equation if the lattice penetration length is small compared to the subgrain diameter. At larger annealing times the grain boundary part of the penetration plot - similarly to Haessner's measurements - was linear with one effective slope. The subgrain and large-angle grain boundary coefficients at 574. 5 K are P//1 equals K//1D//1 . delta equals (1. 9 plus or minus 0. 6) multiplied by 10** minus **2**0m**3/s and P//2 equals K//2D//2. delta equals equals (1. 2 plus or minus 0. 5) multiplied by 10** minus **1**9m**3/s respectively, where delta is the grain boundary width, K is the solute segregation factor and D is the diffusion coefficient. From the temperature dependence of P//2 it was obtained that P//2 equals (3. 1 plus or minus **4**. **2//1//. //8) multiplied by 10** minus **1**5 exp left bracket -(0. 51** plus -0. 04) (eV)//kT right bracket (m**3/s.
|Number of pages||7|
|Publication status||Published - Dec 1 1986|
ASJC Scopus subject areas