کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1450863 | 988749 | 2007 | 11 صفحه PDF | دانلود رایگان |
The effect of grain boundary (GB) type on precipitate-free zone (PFZ) width in friction stir-processed 7075-T7 Al alloy is investigated by transmission electron microscopy (TEM) and stereology. The average half width of PFZs at random GBs is 70.4 ± 0.7 nm. For low-angle GBs, an apparent transition of PFZ half width is observed at a misorientation of 11°. For coincidence site lattice (Σ) GBs, only Σ1, Σ3 and Σ5 have smaller PFZ width than that of random GBs. Crystal-frame stereology is used to recover the GB plane distribution. It is found that the GB plane distribution is relatively isotropic for most Σ GBs. Low/high index plane combinations are observed for most Σ GBs; furthermore, most Σ GBs have both tilt and twist components. The combined results of TEM and stereology suggest that smaller PFZ width is associated only with low Σ GBs since the formation and growth of PFZs at GBs depends closely on the core structure, in addition to the geometric structure of GBs.
Journal: Acta Materialia - Volume 55, Issue 5, March 2007, Pages 1543–1553