Understanding Material Properties: Mechanical, Physical & More

Posted on Mar 13, 2025 in Technology

Mechanical Properties

Hardness: Resistance to being scratched or penetrated by another material.
Toughness: Resistance to breakage when subjected to deformation.
Ductility: Ability to be stretched into threads.
Malleability: Ability to be spread into sheets.
Fatigue: Deformation subjected to repeated loads.
Brittleness: Increased strength and fragility as a result of cold deformation.
Castability: Ability to fill a mold.
Machinability: Ability to be cut by machine tools.

Density: Mass per volume.
Melting Point: The energy required to separate atoms.
Specific Heat: Energy required to raise the temperature by one degree.
Thermal Conductivity: The rate of heat flowing into and through a material.
Resilience: The ability to absorb energy when elastically deformed and release this energy when the load is removed.

Tensile Test: Destructive test measuring the sense of lengthening of the piece.
Hardness Testing:
- Vickers (Pyramid)
- Rockwell (Hardness as a function of tread depth, less precise)
- Mohs (Scratch resistance)
- Brinell (Compresses a steel ball for a while)
Compression Test: Measures the shortening of the piece.
Torsion Test: Measures properties under rotational loads; shear properties are usually determined in this test.
Impact Test: Dynamic test, by shock.
- Charpy (Probe horizontally)
- Izod (Probe vertically)
Fatigue Testing: Subjecting materials to repeated variable loads over time.

Paramagnetic Materials: Do not alter the magnetic field lines of force.
Diamagnetic Materials: Repel force lines, diminishing the magnetism of the magnet.

Medulla: Central part of the tree with a porous, spongy texture. It has a very small diameter, is often cracked in old wood, and is usually discarded during processing.
Heartwood: Innermost and hardest part, with maximum development and strength. Compact, mature wood that is usable. Duraminization process: transformation of sapwood to heartwood.
Sapwood: Outside of the trunk, under the bark. Young tissues during growth (living area), containing sap with organic matter.
Cambium: Base of growth, producing two types of cells: into the interior (wood, sapwood) and out (released).
Liber: Inner part of the bark, stringy and very resistant.
Cortex: Outer layer of the trunk, waterproof fabric that covers the liber and protects the tree.
Radio and Rings:
- Woody rays (radial direction, perpendicular to the growth rings, and disseminate stored nutrients)
- Annual rings (each ring corresponds to annual growth, with two areas formed: light-colored and thin-walled in spring, and dark, dense, thick-walled in summer).