MATS 3011 Lecture Notes - Lead
Document Summary
Solvous (locus of solubility limit of pb in sn) Consider a composition: 40% sn-60% pbthis is composition @ a. Cool down really slowly (eqbm) to point b --> mostly liquid (40%) and traces of alpha (10ish %) @ c --> l (61. 9%) + alpha (18. 3%) + trace of beta (97. 8%) @ point just above c, have l + alpha (almost the same compositions as c) for l, ce = 61. 9% sn for alpha, calpha,e = 18. 3% sn. There"s quite a lot of liquid just above c (use lever rule) Wl just above c = (40 - 18. 3)/(61. 9 - 18. 3) = 0. 4977. Walpha just below c = (97. 8 - 40)/(97. 8-18. 3) = 0. 727. Matsci page 2 no microstructure in a b/c all liquid alpha is rich in lead beta is rich in tin beta most likely forms @ grain boundaries of alpha. For ce just below b, all the liquid is gone alpha is pd rich beta is very rich in sn.
