Question

For a lead�tin alloy of composition 80 wt% Sn�20 wt% Pb and at 180�C (355�F) do the following: (a) Determine the mass fractions of the ? and ? phases. (b) Determine the mass fractions of primary ? and eutectic microconstituents. (c) Determine the mass fraction of eutectic ?.

Answer 1

a). W_$\alpha$ = 97.8 - 80 / 97.8 - 18.3

= 0.224

W_$\beta$ = 1 -  W_$\alpha$

= 1 - 0.224

= 0.776

b). mass fraction of primary, W_$\beta$' = 80 - 61.9 / 97.8 - 61.9

= 0.504

mass fraction of eutectic, We = 1 - W_$\beta$'

= 1 - 0.504

= 0.496