Below shown binary phase diagram describes the system Sn-Bi. T (C) 300- 250- 200- 150- 100- 50- 0+ 0 Sn B X 3 N Y 10 20 30 40 50 60 70 80 90 100 Mass % Bi Bi a) Which phases are present in areas W, X, Y and Z ? What does stand for? (5P)