Dislocation structures in the yttrium aluminum garnet phase of the directionally solidified composites were investigated by means of transmission electron microscopy. In as-grown specimens, dislocation networks which were composed of dislocations with Burgers vectors parallel to <100>, <110> and <111> were observed. In specimens which were deformed at 1773K, both dislocation networks and isolated dislocations with Burgers vectors of a<100> and a/2<111> were observed; but neither of them were glide dislocations. In specimens which were deformed at room temperature, isolated dislocations with a Burgers vector of a/2<111> were observed. They were identified as being glide dislocations which lay on {110} planes.

Dislocations in the YAG Phase of Directionally Solidified Al2O3/YAG Deformed at Room and High Temperatures. W.Moon, H.Saka, Y.Waku: Materials Transactions, 1999, 40[7], 627-33