Thermodynamics: Microstructure

What is a binary system? What is an isomorphous system?

In the Cu-Ni system: Microstructure development for: Co = 35wt%Ni.

Cu-Ni system

BINARY-ISOMORPHOUS SYSTEMS

• Fast rate of cooling: Cored structure

• Slow rate of cooling: Equilibrium structure

CORED VS EQUILIBRIUM PHASES

• How does solid solution affect tensile strength and ductility?

MECHANICAL PROPERTIES: Cu-Ni System

Cu-Ag system

BINARY-EUTECTIC SYSTEMS What is a eutectic system? In the Cu-Ag system: How many single phase regions? What is the major component in the α phase? What is the major component in the β phase? TE and CE

• For a 40wt%Sn-60wt%Pb alloy at 150C What are the phases present in the material? What is the composition for each phase?

Pb-Sn EUTECTIC SYSTEM (1)

What is the relative amount of each phase?

Pb-Sn EUTECTIC SYSTEM (2)

Pb-Sn system

MICROSTRUCTURES IN EUTECTIC SYSTEMS

Microstructure when Co < 2wt%Sn?

MICROSTRUCTURES IN EUTECTIC SYSTEMS-I

Microstructure when 2wt%Sn < Co < 18.3wt%Sn?

Pb-Sn system

MICROSTRUCTURES IN EUTECTIC SYSTEMS-II

Microstructure when Co = CE? Pb-Sn

system

Adapted from Fig. 9.11, Callister 6e.

MICROSTRUCTURES IN EUTECTIC SYSTEMS-III

The concept of microconstitutents?

Pb-Sn system

• Microstructure when 18.3wt%Sn < Co < 61.9wt%Sn?

MICROSTRUCTURES IN EUTECTIC SYSTEMS-IV

HYPOEUTECTIC & HYPEREUTECTIC