MECH Dept Engineering Topics List

Definition, Formula, Calculation | Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

Atomic packing factor is defined as the ratio of the volume of the atoms per unit cell to the total volume occupied by the unit cell.

Definition, Formula, Calculation | Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

Atomic radius is defined as half the distance between the nearest neighbours in a crystal of a pure element.

Definition, Calculation | Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

The coordination number is defined as the number of nearest atoms which are directly surrounding a given atom.

Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

A unit cell is characterised by 1. An effective number of atoms, 2. Coordination number, 3. Atomic radius, 4. Atomic packing factor, and 5. Void space and density. 1. An effective number of atoms, 2. Coordination number, 3. Atomic radius, 4. Atomic packing factor, and 5. Void space and density.

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

It has been found that most of the common metals possess cubic or hexagonal structures only.

Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

Crystals possess different external symmetries which are described by certain mental operation.

Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

The Table 0.2 shows the 14 basic Bravais lattices along with their characteristics.

Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

In 1848, Bravais showed that there are only fourteen different ways of arranging lattice points in space such that all the points have exactly the same environment.

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

All crystals are classified into seven systems on the basis of the shape of the unit cells.

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

The various terms associated with crystallography are:

Crystal Physics

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

From the point of view of crystal structure, materials can be broadly classified into : 1. Crystalline, and 2. Non-crystalline or Amorphous.

Introduction

Subject and UNIT: Engineering Materials and Metallurgy: Unit 0: Review of Crystal Physics

The matter is usually found to exist in solids and fluids (i.e., liquids and gases). All these materials consist of atoms and molecules.