Material Properties: Mechanical, Physical, and More

Posted on Feb 11, 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 resulting from 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.

Physical Properties

  • Density: Mass per volume.
  • Melting Point: The temperature at which a solid changes to a liquid.
  • Specific Heat: Energy required to raise the temperature of a substance by a certain amount.
  • Thermal Conductivity: The rate of heat flow through a material.
  • Resilience: The ability to absorb energy when elastically deformed and release that energy upon unloading.

Material Tests

  • Tensile Test: Destructive test measuring the resistance of a material to a pulling force.
  • Hardness Testing:
    • Vickers: Pyramid indentation method.
    • Rockwell: Hardness based on indentation depth (less precise).
    • Mohs: Scratch resistance scale.
    • Brinell: Compresses a steel ball into the material.
  • Compression Test: Measures the resistance of a material to a compressive force.
  • Torsion Test: Measures the shear properties of a material under rotational loads.
  • Impact Test: Dynamic test involving sudden shock.
    • Charpy: Specimen is horizontal.
    • Izod: Specimen is vertical.
  • Fatigue Testing: Subjecting a material to repeated stress cycles over time.

Electrical, Magnetic, and Optical Properties

  • Paramagnetic Materials: Do not significantly alter the magnetic field.
  • Diamagnetic Materials: Repel magnetic field lines, diminishing the magnetism.

Wood Structure

  • Medulla: Central, porous part of the tree, often discarded.
  • Heartwood: Innermost, hard, and mature wood, providing maximum strength.
  • Sapwood: Outer part of the trunk, containing living tissues and sap.
  • Cambium: Growth layer producing wood (sapwood) and bark.
  • Liber: Inner bark, fibrous and resistant.
  • Cortex: Outer bark layer, protecting the tree.
  • Radio and Rings:
    • Woody Rays: Radial direction, for nutrient transport.
    • Annual Rings: Indicate annual growth, with spring and summer wood.

Plastic Types

  • PET: Polyethylene Terephthalate – Used for soda, water bottles, etc.
  • HDPE: High-Density Polyethylene – Used for milk jugs, detergent bottles, etc.
  • PVC: Polyvinyl Chloride – Used for pipes, hoses, cables, etc.
  • LDPE: Low-Density Polyethylene – Used for bags, films, etc.
  • PP: Polypropylene – Used for food packaging, automotive parts, etc.
  • PS: Polystyrene – Used for food containers, toys, etc.
  • PC: Polycarbonate
  • PA: Polyamide
  • PU: Polyurethane
  • ABS: Acrylonitrile Butadiene Styrene
  • PMMA: Polymethyl Methacrylate