Figure 5

TEM characterization of melt-spun ribbons. TEM images of an Al-BNNT (3 wt.%) composite ribbon near the fractured surface after a tensile test. (a) The smallest Al grains found in the melt-spun Al-BNNT matrix; the inset depicts an EDS pattern recorded from this area. (b, c) A triple grain boundary in the Al-BNNT matrix at various magnifications; the central inset in (b) shows a representative X-ray spectrum confirming no other phases formed in the matrix except Al; the (110). (200), (220), and (311) Al peaks are marked. (c) In this case, the Al matrix is nicely oriented along the [110] zone axis of the fcc Al lattice. (d to f) A fading contrast peculiar to images relevant to individual multiwalled BN nanotubes present in the fractured ribbons either within the grains (d to e) or along the grain boundaries (f).