Solidification of the metal

Pure metal Metal alloy

Tem

pera

ture

Time

Pouring temperature

Freezing begins

Freezing ends

•Local solidification time•Total solidification time

Time

Pouring temperature

Freezing begins

Freezing ends

Alloy formation: by solid solution

• Solvent atom (Fe)• Solute atom (c)

Alloy: steel

Substitutional solid solution Interstitial solid solution

Ex: Brass: Cu(Zn) Ex: Steel Fe (C)

Intermetallic Compound• No of atoms of constituent-elements are in specific ratio.

• Some intermetallic compounds have solid solubility

• They are strong hard and brittle.

• Bond: metallic or ionic

• Example: CuAl2 (precipitation hardening)

Two-phase alloysPhase:

Two-phase system:

• First phase is a solid solutionSecond phase particle disparsement Ex: Cu-Pb

• OR may have two sets of grains

Phase diagrams

Lever rule: to calculate the wt. fraction of solid and liquid phase

Pb-Sn binary phase diagram

Fe-C system

Cast structure of pure metal

Open and Closed Mould

Sand Casting (Expandable-mould, Permanent-pattern Casting)

Use of chaplets to avoid shifting of cores

Possible chaplet design and casting with core

Use of chills