UNIT I CONSTITUTION OF ALLOYS

1. 20ME304--ENGINEERING
METALLURGY

2. UNIT I --CONSTITUTION OF ALLOYS
• Constitution of alloys – Solid solutions,
substitutional and interstitial – phase
diagrams, Lever rule, Isomorphous, eutectic,
eutectoid, peritectic and peritectoid reactions,
Iron – Iron carbon equilibrium diagram –
Classification of steels and cast irons,
microstructure, properties and applications –
Ferrite and austenite stabilizers.

3. UNIT-I
CONSTITUTION OF ALLOYS

4. IMPURITIES IN SOLIDS
• Impurities are always present in all materials.
ALLOY:
• It is a mixture of two or more metals. Metal and
a non metal.

5. SOLID vs LIQUID SOLUTON

6. HUME ROTHERY’S RULES
• The solute and solvent follows the following
general rules:
1. Size factor (similar size)
2. Crystal structure(same crystal structure)
3. Valence (same valence)
4. Electronegativity (approximately same electro
negativity)

7. TYPES OF SOLID SOLUTIONS
1. Substitutional solid solutions
(mixture of two elements, substitute for a
parent element)
a) Random b)Ordered
2.Interstital solid solutions
(the solute atom fit in to the space between
solvent and parent atom)

10. PHASE DIAGRAM

11. PHASE DIAGRAM OF PURE SUBSTANCE
(ONE COMPONENT PHASE DIAGRAM)

12. GIBBS PHASE RULE
• F=C-P+2
• Where, c= number of components
• P= number of phases

13. PHASE DIAGRAM FOR PARTIALLY SOLID
SOLUTION (16 mark)
• SIX PHASES IN THE REGION
1. LIQUID PHASE
2. ALPHA SOLID SOLUTION PHASE
3. BETA SOLID SOLUTION PHASE
4. ALPHA + LIQUID PHASE
5. BETA + LIQUID PHASE
6. ALPHA + BETA SOLID SOLUTION PHASE (eutectic
point)

14. PHASE DIAGRAM FOR PARTIALLY SOLID
SOLUTION