This document discusses alloys and phase diagrams. It defines a binary alloy as a mixture of two metals and describes an isomorphous system as one where the two metals are completely soluble in both the liquid and solid states, forming a single crystal structure. The phase diagram for a binary isomorphous alloy system is divided into three zones by the liquidus and solidus lines: a liquid zone above the liquidus line, a liquid+solid zone between the lines, and a solid zone below the solidus line. Examples of isomorphous systems given are copper-nickel, antimony-bismuth, gold-silver, and chromium-molybdenum. Questions at the end ask to differentiate isomorphous and e

1. ME 8491 ENGINEERING METALLURGY
M.KARTHIKEYAN
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
AAA COLLEGE OF ENGINEERING & TECHNOLOGY, SIVAKASI
karthikeyan@aaacet.ac.in

2. Constitution of alloys – Solid solutions, substitutional
and interstitial – phase diagrams, Isomorphous,
eutectic, eutectoid, peritectic, and peritectoid reactions,
Iron – carbon equilibrium diagram. Classification of steel
and cast Iron microstructure, properties and application.
UNIT I ALLOYS AND PHASE DIAGRAMS

3. A mixture of two metals is called a binary alloy.
Isomorphous system:
 Two metals completely soluble in the liquid state and solid state.
 Single type of crystal structure exists.
The phase diagram is divided into three separate areas
 Liquid zone
 Liquid + Solid zone
 Solid zone
ISOMORPHOUS SYSTEM OR PHASE DIAGRAM FOR BINARY
ISOMORPHOUS ALLOY SYSTEM

5. The phase diagram is divided into three separate areas by two phase
boundaries namely
 Liquidus line.
 Solidus line.
 Above the Liquidus line – uniform liquid solution.
 Below the Solidus line – single solid solution.
 Between the Liquidus & Solidus line – liquid and solid solution
solution coexist.
Examples of Isomorphous system:
 Copper – nickel system.
 Antimony – Bismuth system.
 Gold – silver system.
 Chromium – Molybdenum system.

6. 1. Differentiate isomorphous and eutectic reaction
2. Draw a typical phase diagram of isomorphous alloy system
3. Explain the isomorphous system and peritectoid reaction
QUESTIONS