Burgers vector transition

However, the monolithic compounds possess a lack of room temperature ductility and toughness because of their complex lattice structures and sessile superdislocations with large Burgers vectors. The brittle-ductile transition temperatures of these silicides are quite high of the order of 800 to 1050 °C, respectively. 

The interfaces between finescale exsolution lamellae of ilmenite in hematite have been investigated and most were shown to be coherent and dislocation free [251]. Due to differences in lattice parameters, dislocation arrays decorate the interface [Fig. 8(b)]. Contrast analysis revealed a hexagonal grid of rhombohedral dislocations [250] rather than dislocations with basal Burgers vectors [252]. The ordering phase transition in ferrian ilmenite from the high-temperature R3c disordered structure to a R3 lower-temperature ordered structure results in the creation of twin domains [253,254]. No dislocations were involved. 

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