Material Properties & Classifications

Understanding Material Properties and Types

Material Classification by Origin

• Raw Materials: Substances used for crafting objects or other materials.
• Natural Materials: Found in nature.
• Manufactured Materials: Obtained after an industrial process.
• Recycled Materials: Can be reused after initial use.

Material Families: A Technological Perspective

From a technological point of view, materials are categorized into five main families:

• Wood: Includes all types of wood, paper, and cardboard.
• Metals:
  • Natural: Such as iron (Fe), tin (Sn), aluminum (Al), copper (Cu), gold (Au), silver (Ag), platinum (Pt), lead (Pb), and zinc (Zn).
  • Artificial (Alloys): Like steel (Fe+C), bronze (Cu+Sn), or brass (Cu+Zn).
• Plastics: Mostly artificial, with exceptions like natural rubber.
• Stone/Ceramics: Examples include marble, granite, slate, quartz, sandstone, limestone, and various gemstones.
• Fabrics: Comprises materials like wool, linen, cotton, animal skin, and leather.

Technological Properties of Materials

The technological properties of materials include, among others:

• Malleability: The ability to be transformed into thin layers or sheets. This is typical in metals, such as aluminum foil.
• Ductility: The ability to be drawn into threads or wires. Common in metals, like copper wires or steel wire used for fences.
• Weldability: The ability to join with other materials when heated. For example, the tin used in electronic circuits.
• Fusibility: The ability to be melted under heat and then molded into a specific shape.

Physical Properties of Materials

The physical properties of materials are:

• Hardness: The ability of one material to scratch another. It classifies materials from hard to soft. The most famous scale for hardness is the Mohs Scale, where talc is the softest (level 1) and diamond is the hardest (level 10).
• Tenacity: The ability to resist impact. It categorizes materials from resistant to fragile. Glass, for instance, is hard but fragile.
• Elasticity: The capacity of materials to return to their original shape once the deforming stress is removed. This divides materials into elastic (they return to their original shape) and plastic (they do not recover their shape).
• Density: Expresses the ratio between mass and volume, defined by the formula D=m/V. When considering "What is heavier, a kilogram of iron or a kilogram of straw?", the answer is that they have the same weight. However, a kilogram of iron occupies less space than a kilogram of straw, meaning iron is denser than straw. The standard unit for density is kg/m³ (kilograms per cubic meter). For smaller quantities, g/cm³ can be used. To convert g/cm³ to kg/m³, multiply by 1000.

  Remember: Cubic units scale by factors of one thousand (e.g., 1 m³ = 1000 dm³ = 1,000,000 cm³).