Toughness

Toughness is the total amount of energy a material can absorb until fracture. This feature represents the material’s coup like capacity to absorb energy under external loads. Toughness is directly related to the area under the stress-strain curve, which indicates the energy absorbed per unit volume.

A material with high toughness is expected to have both high ductility and high strength. Brittle materials with high strength but low ductility, and materials with low strength but high ductility, are not tough. Toughness depends on both parameters being high.

The unit of toughness is joule per cubic meter (J·m⁻³).

Materials with High Toughness

• Structural steel
• Stainless steel
• Titanium
• Aluminum alloys
• Copper
• Brass

Materials with Low Toughness

• Ceramics
• Glass
• Concrete
• Cast iron
• Hardened steel

Toughness Test

The notch impact test can be used to determine a material’s toughness value. For this, rectangle a specimen is prepared with a notch at its center. The specimen is then fixed to a specific base. A pendulum hammer is released from a specified height to strike the specimen. The energy absorbed during fracture is measured to calculate the material’s toughness.

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