Status Chapter 03, Phase Diagrams

Well hello everyone,

   I worked a little on chapter Phase Diagrams. I have put up some posts related to the same on this blog. The posts mentioned below

• Introduction
• Basics of Phase diagrams
• Eutectic reaction
• Tie Line
• Old Questions, Material Science, Chap 3
• Phase diagrams & Lever Rule
• Triple Points & Gibbs Rule
• Presentation on Binary Isomorphous System
• Eutectic Systems

There is lot more to be covered and shall do the same at the earliest. The schedule for exams is out also. So gonna hurry up from now on.

Hope your preparation is going on at good pace

Don't forget to grab a copy of Material Science and Engineering book, which is essential for preparing for AMIE, Material Science.

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Elasticity and Plasticity

Elasticity:

       External loads tend to deform materials from their original shape and size. Elasticity is the ability of a material to return to its original shape and size after removing the load applied. Elastic deformation (change of shape or size) lasts only as long as a deforming force is applied to the object, and disappears once the force is removed.This is so because the atoms in the metal change their position due to external stress but can't take new positions because the change of position is too small (or in acceptable range)

     Steels and other such materials are elastic over good range.

Plasticity:

     External loads tend to deform materials from their original shape and size. Plasticity is the ability of a material to retain the deformation even after external load is removed.In plastic deformation, the atoms in the material due to external force are displaced and take up new positions. They cannot come back to their natural positions once force is removed.

     This is very desirable property in machine tools. Lead has good plasticity at room temperature. Cast Iron has no plasticity even at very high temperature.    

PS: Some of the info here is taken from science.jrank.org & from Wikipedia. Please do refer to them for further info

with warm regards

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Poisson's Ratio

Poisson's ratio (ν), is the ratio, when a sample object is stretched, of the contraction or transverse strain (perpendicular to the applied load), to the extension or axial strain (in the direction of the applied load).

When a material is compressed in one direction, it usually tends to expand in the other two directions perpendicular to the direction of compression. This phenomenon is called the Poisson effect. Poisson's ratio ν (nu) is a measure of the Poisson effect

In the above picture, the stress is acting in X axis, but change in object is evident in Y and Z axes also. Poisson's effect is all about this change and Poisson's ratio is a measure of this effect and is given by 

For ideal material, the ratio is 0.5. But in general it ranges from 0.25 to 0.40.

with warm regards

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PS: Some of the info here is taken from Wikipedia. Please do consult them for more info

Mechanical Properties of Materials

Hello Everyone,

  Well I am a little tensed. Exam dates have been released. My preparation till now amounts to almost nothing and the pressure is huge. So started serious study from today morning itself.

  So stated with chapter called as Mechanical Properties of Materials. So the important topics to be studied here include:

• Tensile strength
• Poission's Ratio
• Yield strength
• Elastic and viscoelastic properties
• Creep, stress relaxation and impact.
• Fracture behaviour.
• Ductile fracture
• Griffith theory
• effect of heat treatment and temperature on properties of metals.

Well I stated at-last. Will see what is gonna happen at the D-Day

with warm regards

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Summer Schedule for 2011

The IEI has released dates for the examinations of Summer 2011. Please do find the same here:

Amie 2011 Summer Tt

with warm regards

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