Material Properties: Mechanical, Thermal, and Technological Characteristics

Previous Concepts

Stress: The applied force per unit area.

Elongation: Deformation of a material under the action of a force.

Reduction in Area: The decrease in cross-sectional area.

General Properties

• Impenetrability: The volume occupied by a body cannot be occupied by another simultaneously.
• Severability: Divisible parts can be increasingly smaller.
• Porosity: Having pores.
• Compressibility: The ability of bodies to decrease their volume by applying pressure.
• Affinity: The force that unites similar materials.
• Adhesion: Attraction established between bodies whose surfaces are in contact.
• Solubility: The ability to dissolve and disperse within a liquid.
• Specific Gravity: The ratio of a body's weight to the weight of an equal volume of a reference substance.

Mechanical Properties

• Resistance: The ability of a material to resist deformation.
• Tenacity: The ability to deform without breaking.
• Hardness: Resistance to penetration by another hard body.
• Resilience: A metal's resistance to impact.

Technological Properties

• Malleability: The ability of a metal to take a given form.
• Ductility: The ability to be drawn into a wire.
• Machinability: Breaking the molecular cohesion by applying a force.
• Solderability: The ability of parts to be joined by adhesion (e.g., welding).
• Hardenability: The capacity of hardness to be modified by particle rearrangement.
• Fusibility: The ability to melt.

Thermal Properties

• Heat of Fusion and Heat of Evaporation: The heat required to produce melting and evaporation, respectively.

Destructive Testing

Static

Tension, compression, shear, flexure, torsion, and roll forming.

Dynamic

Impact resistance, resilience.

Additional Tests

Hardness and wear (e.g., Brinell).

Hardness Testing

Rockwell, Vickers, Shore.

Trial Work

Cold, hot, and bending folds; punching; flattening; drawing.

Chemical Tests

Determine qualitative and quantitative composition.

Non-Destructive Testing

Detects faults without disrupting operation, e.g., liquid penetrant, magnetic particle, ultrasound, and radiography.

Concept of Crystalline Materials

Crystal Structure

The geometry of how atoms are arranged.

Lattice

A three-dimensional arrangement of points where every point has identical neighbors.

Unit Cell

The smallest group of atoms representing a particular crystalline structure.

Coordination Number

The number of atoms that touch a given atom.

Network Parameter

Lengths of the sides of the unit cell.