Low permeability molds and low pouring temperature of the molten metal causes ......................... defect in castings.

The problem of shrinkage cavity is more likely to occur while casting ......... A ............ B.......... a chill block

(A.) metal / plastic , (B.) with / without.

For casting of turbine blades made of high temp and high strength alloys, the most suitable process is

For the same material, powder metallurgy process is superior to casting for