1. Ex: Phase Diagram: Water-Sugar System THE SOLUBILITY LIMIT

2. Components: The elements or compounds which are mixed initially (e.g., Al and Cu) Phases: The physically and chemically distinct material regions that result (e.g.,  and  ). Aluminum- Copper Alloy COMPONENTS AND PHASES

3. Changing T can change # of phases: path A to B. Changing C o can change # of phases: path B to D. water- sugar system EFFECT OF T & COMPOSITION (C o )

4. Tell us about phases as function of T, C o, P. PHASE DIAGRAMS For this course: --binary systems: just 2 components. --independent variables: T and Co (P = 1atm is always used).

5. PHASE DIAGRAM FOR Cu-Ni SYSTEM

6. Rule 1: If we know T and C o, then we know: --the # and types of phases present. Cu-Ni phase diagram PHASE DIAGRAMS: # and types of phases

7. Rule 2: If we know T and C o, then we know: --the composition of each phase. Cu-Ni system PHASE DIAGRAMS: composition of phases

8. Rule 3: If we know T and C o, then we know: --the amount of each phase (given in wt%). Cu-Ni system Examples: PHASE DIAGRAMS: weight fractions of phases

9. Sum of weight fractions: Combine above equations: A geometric interpretation: THE LEVER RULE: A PROOF

10. Phase diagram: Cu-Ni system. System is: --binary i.e., 2 components: Cu and Ni. --isomorphous i.e., complete solubility of one component in another;  phase field extends from 0 to 100wt% Ni. Consider C o = 35wt%Ni. Cu-Ni system EX: COOLING IN A Cu-Ni BINARY

11. Effect of solid solution strengthening on: --Tensile strength (TS)--Ductility (%EL,%AR) --Peak as a function of C o --Min. as a function of C o MECHANICAL PROPERTIES: Cu-Ni System

12. 2 components has a special composition with a min. melting T. Cu-Ag system BINARY-EUTECTIC SYSTEMS

13. C o < 2wt%Sn Result: --polycrystal of  grains. MICROSTRUCTURES IN EUTECTIC SYSTEMS-I

14. 2wt%Sn < C o < 18.3wt%Sn Result: --  polycrystal with fine  crystals. Pb-Sn system MICROSTRUCTURES IN EUTECTIC SYSTEMS-II

15. C o = C E Result: Eutectic microstructure --alternating layers of  and  crystals. Pb-Sn system MICROSTRUCTURES IN EUTECTIC SYSTEMS-III

16. Pb-Sn system 18.3wt%Sn < C o < 61.9wt%Sn Result:  crystals and a eutectic microstructure MICROSTRUCTURES IN EUTECTIC SYSTEMS-IV

17. HYPOEUTECTIC & HYPEREUTECTIC

18. INTERMEDIATE PHASES

19. INTERMEDIATE COMPOUND

20. H 2 O – NaCl PHASE DIAGRAM

21. IRON-CARBON (Fe-C) PHASE DIAGRAM

22. HYPOEUTECTOID STEEL

23. HYPEREUTECTOID STEEL