University:
McMaster University
Course:
MATLS 2H04 | Introduction to Materials Engineering
Academic year:

2023
Views:

335

Pages:

2
Author:

Sabrina S.

Hume Rothery Rules for Substitutional SS For 2 elements to easily dissolve in each other they should have similar: atomic size (eg. Ni and Cu) crystal structure electronegativity valence Phase Diagram Example A phase diagram is a thermodynamic map to the equilibrium phases present in an alloy e.g. 40% Sn & 60% Pb at 200°C alpha phase: Pb (solvent phase) - Sn (solute phase) beta phase: Sn (solvent phase) - Pb (solute phase) 7.9 Phase Diagrams: Alloy Constitution Alloy constitution is described by: phases present composition of each phase weight fraction of each phase Binary Phase Diagram Cu-Ni system is termed isomorphous due to the complete liquid & solid solubility of 2 components alpha phase: substitutional solid solution of Cu & Ni liquid phase: homogeneous liquid solution of Cu & Ni Composition Lo determined by the lines Lo metal at 1250°C with 35% Nickel Solidus line Liquidus line 32% Ni 68% Cu 100% solid 43% Ni 57% Cu 100% liquid Weight Fraction - Lever Rule Lo used to determine the amount of each phase present Lo for the amount of each phase present at B construct the line distance to solidus S = 8 distance to liquidus L = 3 Wo (fraction of solid phase) = S / (S+L) = 8 / (8+3) x 100 = 73% WL (fraction of liquid) = L / (S+L) = 3 / (8+3) x 100 = 27% Temperature (°C) 1300 1250 1200 1100 1000 900 800 700 600 500 400 300 200 100 Composition (wt% Cu) 0 10 20 30 40 50 60 70 80 90 100