casting of superalloys

Question 1

what are the types of casting in super alloys

Answer 1

conventional casting-
uses ceramic mold were the solidutcation starts at the walls and stops when the grains meet each other
directionally solidified casting-
mould is heated and supported on water bed
grains nucleate from chilled end upwards giving no transverse boundaries
single crystal casting-
similar to Ds but has pig tail constriction on the feed that allows only the most favourably orientated grains grow through, this gives a full single grain which gives high resistance to creep and thermal shock.