A turbine wheel e is being manufactured using a die casting

A turbine wheel (e) is being manufactured using a die casting operation. Identify the four defects shown in the following figures:

a. the first one is porosity which occurs due to air entrapment

b. voids which occurs due to incomplete filling of cavity.

c. scars which occurs due to insufficient hardness of the mould cavity.

d. craks. it occurs due to hydrogen imbrittlement because hydrogen gets entrapped during casting.