Malleability is a mechanical property that describes a material’s ability to undergo plastic deformation under compressive stress without fracturing. It reflects how easily a material can be shaped into thin sheets or other forms by processes such as rolling, hammering, or pressing. Malleability is especially important in manufacturing operations like forging, extrusion, and sheet metal forming.
Characteristics of Malleability
- Plastic Deformation Under Compression
- Malleability is specifically concerned with a material’s response to compressive forces, distinguishing it from ductility, which pertains to tensile forces.
- Highly malleable materials can undergo extensive deformation without cracking or breaking.
- Material Dependence
- Malleable materials typically have a high degree of plasticity and low internal resistance to dislocation motion.
- Examples of highly malleable materials include gold, silver, aluminum, and copper.
- Temperature Effects
- Many metals become more malleable at higher temperatures due to increased atomic mobility. This principle is exploited in processes like hot rolling and hot forging.
Malleability vs. Ductility
- While both properties are forms of plasticity, their distinction lies in the type of stress:
- Malleability: Response to compressive stress (e.g., hammering into sheets).
- Ductility: Response to tensile stress (e.g., stretching into wires).
- Some materials are highly malleable but not very ductile. For example, lead is extremely malleable but has low tensile strength and ductility.