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

Poor collapsibility of the mold leads to .......... type of casting defect in aluminium castings.