Definition: Energy stored in a material up to the elastic limit.
Key Idea: Fully recoverable when the load is removed.
Importance: High resilience means the material can absorb shocks without permanent deformation.
Examples: Spring steel, rubber bands.
Definition: Energy absorbed beyond the yield point until fracture.
Key Idea: Causes permanent deformation.
Importance: Indicates how much a material can plastically deform before breaking.
Examples: Copper, aluminum.
Definition: Total energy absorbed until fracture (entire area under curve).
Key Idea: Measures ability to absorb energy before breaking.
Examples: Mild steel (high toughness), glass (low toughness).
Definition: Maximum stress a material can withstand without permanent deformation.
Key Idea: Beyond this, the material will not return to its original shape.
Examples: Low‑carbon steel has a clear elastic limit.
Definition: Stress at which noticeable plastic deformation begins.
Key Idea: Material starts to flow permanently without much increase in load.
Examples: Mild steel shows a distinct yield point.
Definition: Maximum stress the material can withstand.
Key Idea: Beyond this, necking begins and engineering stress decreases.
Examples: Structural steels, aluminum alloys.
Definition: Final breaking point of the material.
Key Idea: Specimen fails and separates into pieces.
Examples: Brittle fracture in glass, ductile fracture in mild steel.
| Property | Ductile Materials | Brittle Materials |
|---|---|---|
| Definition | Materials that undergo significant plastic deformation before fracture. | Materials that fracture with little or no plastic deformation. |
| Stress–Strain Curve | Long curve with clear yield point, large plastic region, high toughness. | Short curve, almost linear until sudden fracture, low toughness. |
| Energy Absorption | Absorb large amounts of energy before breaking. | Absorb very little energy before breaking. |
| Fracture Behavior | Necking and gradual failure. | Sudden, catastrophic failure. |
| Examples | Mild steel, copper, aluminum. | Glass, cast iron, ceramics. |