Ductile Material vs Brittle Material: Difference and Comparison

Key Takeaways

1. Ductile materials can deform under tension, brittle cannot.
2. Ductile retains shape after stretching, brittle fractures.
3. Ductile fails gradually, brittle suddenly.

What is Ductile Material?

Ductile materials are defined as materials that show plastic deformation before fracture. In other words, these materials are known to go through substantial plastic deformation when the load is applied without fracturing. 

Unlike brittle materials, which are not able to withstand the load and break down, ductile material has a significant property to withstand the applied load beyond their yield points and is able to elongate into thin wires and sheets.

Ductile materials exhibit high energy absorption under tensile testing. Also, the fracture behaviour delineated by the ductile materials tends to undergo necking before fracture. Some examples of ductile materials are – copper (Cu), mild steel, rubber, aluminium (Al), and most plastics. 

What is Brittle Material?

Brittle materials are defined as materials that show imperceptible plastic deformation. In other words, these are the materials on which, when applied, the load breaks down abruptly or stressfully. 

Unlike ductile materials that have the ability to undergo substantial deformation before failure, brittle materials fail to do so. This is due to the atomic and microstructural arrangement of the materials that do not have the ability to incorporate plasticity. 

Brittle materials exhibit low energy absorption under tensile testing. Also, the brittle materials advertise the fracture behaviour where fractures occur suddenly and without significant deformation. Some examples of brittle materials are cast iron (Fe), stone, ceramics (cement, glass, concrete, etc.), and ice. 

Difference Between Ductile Material and Brittle Material

1. Ductile materials are defined as materials that show plastic deformation before fracture. Whereas on the other hand, brittle materials are defined as materials that show imperceptible plastic deformation.
2. Considering the percentage elongation in the case of ductile materials is higher before fracture under the tensile strength. While comparatively, on the other hand, the percentage elongation in the case of brittle materials is less before fracture under the tensile strength.
3. Ductile materials exhibit high energy absorption under tensile testing. At the same time, brittle materials exhibit low energy absorption under tensile testing.
4. In the case of fatigue loading, ductile materials show a longer lifespan. On the other hand, it shows a shorter lifespan for brittle materials.
5. Some examples of ductile materials are – copper (Cu), mild steel, rubber, aluminium (Al), and most plastics. While, comparatively on the other hand, some examples of brittle materials are – cast iron (Fe), stone, ceramics (like – cement, glass, concrete, etc.), and ice.
6. Ductile materials can undergo varied forming operations such as rolling, drawing, forging, bending, etc. Whereas on the other hand, brittle materials cannot undergo any forming operations. For example – Cast iron cannot be drawn into wires.
7. Talking about Young Modulus, ductile material has a low modulus, while in the case of brittle material, it is high.
8. The fracture behaviour delineated by the ductile materials tends to undergo necking before fracture. At the same time, the brittle materials advertise the fracture behaviour where fractures occur suddenly and without significant deformation. 

Comparison Between Ductile Material and Brittle Material

Parameter of Comparison	Ductile Material	Brittle Material
Definition	The materials that show plastic deformation before fracture	The materials that show imperceptible plastic deformation
Percentage elongation	Higher	Lower
Energy Absorption	More	Less
Fatigue Loading	They show a longer lifespan	They exhibit a shorter lifespan
Examples	Copper, Mild steel, rubber, aluminium, and most plastics	Cast iron, stone, ceramics (like – cement, glass, concrete, etc.), ice
Forming Operations	Such as rolling, bending, forging, etc., can be formed on materials	It cannot be performed on the materials. For example – Cast iron cannot be drawn into wires
Young Modulus	It shows the low modulus	It shows the high modulus
Fracture Behaviour	Tend to undergo necking before fracture	The fracture occurs suddenly and without significant deformation

References

1. https://www.sciencedirect.com/science/article/abs/pii/S0142112318301208
2. https://www.sciencedirect.com/science/article/abs/pii/S0142112309000073