Why is it preferable to precipitationharden alloys such as A

Solution

it is preferable to first quench the alloy to a lower temp becouse after quenching to a lower temp the grain size of the alloy becomes very small and the alloy becomes hardand brittle. Now we will reheat upto the aging temperature becouse it will enhances grain growth and alloy becomes soft and gains ductility and losses brittleness which is very essential.

However if directly quench the material to the aging temperature the alloy will becomes hard and brittle and will be of limited use. So to make the alloy soft and ductile and with appropriate hardness,reheating is neccessary.