Cite the phases that are present and the phase compositions for the following alloys: (a) 90 wt% Zn-10 wt% Cu at 400C (750F) (b) 75 wt% Sn-25 wt% Pb at 175C (345F) (c) 55 wt% Ag-45 wt% Cu at 900C (1650F) (d) 30 wt% Pb-70 wt% Mg at 425C (795F) (e) 2.12 kg Zn and 1.88 kg Cu at 500C (930F) (f) 37 lbm Pb and 6.5 lbm Mg at 400C (750F) (g) 8.2 mol Ni and 4.3 mol Cu at 1250C (2280F) (h) 4.5 mol Sn and 0.45 mol Pb at 200C (390F)

Steel balls 12 mm in diameter are annealed by heating to 1150 k and then slowly cooled to 400 k in an air att 325 k and h -20 w/m2 k. assume the properties of the steel to be k- 40 w/m k,p 7800 kg/m3, and cp 600 j/kg k. a. determine whether lumped system method can be used to analyze this problem and if so why" b. determine the time required for the cooling process. c. determine the total amount of heat lost from each ball to the ambient air