Dislocation Structures in Single‐Crystal Al2O3

摘要: Abstract : Chemical polishing and etching techniques were usedto reveal the dislocation structures of sapphire ruby crystals grown by flamefusion flux techniques. The average density edge dislocations lying in prism planes was 3.0 X 10 to 5th power/sqcm which could be changed only slightly chromium additions annealing at 2000 C. An basal 2 6th decreased 35 80% on annealing. Crystal orientation (i.e., angle between c axis growth axis) showed no effect but a pronounced subboundary arrangement density. substructure 0 degree more complex than that 90 crystals; 60 possessed structure intermediate degree. Principal observations included (1) prismatic slip all as-grown (2) profuse slip, readily polygonized annealing; (3) densities lower those Verneuil (4) rare form twinning, crystals. (Author)