Question

3. Specify the amount of each phase present at 150°C for 7.5 kg of a Pb-30% Sn alloy. Composition a n 0 20 40 Temperature (°F) Composition

Answer 1

Initial conditions

Temperature T (Point B) = 150°C

Wt% of Pb = 30%

Wt% of Sn(Point A) = 70%

Mass of alloy = 7.5 kg

Intersection point C occurs from point A and point B

At this point C only two phase exists α and β phase

Composition of β phase at point E

Wt% of Sn = 98%

Wt% of Pb = 2%

Mass of Sn = 0.98*7.5 = 7.35 kg

Mass of Pb = 0.02*7.5 = 0.15 kg

Composition of α phase at point F

Wt% of Sn = 10%

Wt% of Pb = 90%

Mass of Sn = 0.10*7.5 = 0.75 kg

Mass of Pb = 0.9*7.5 = 6.75 kg

Componition (at% Sn) 100 20 40 60 80 327C 600 300 Liquid 500 232'C 400 200 163'C 619 143 97 50 300 00 200 100 0 100 40 60 구0, 80 981 (Sn) Compostion (wt% Sn (4aungruadu &Phne 20