Chapter 4, Problem 4.1QP

Name the two primary factors that make aluminum an attractive structural engineering material.

To determine

Two primary factors that make aluminum an attractive structural engineering material.

Explanation of Solution

List the two primary factors that make aluminum an attractive structural engineering material:

• Ability to resist corrosion
• High strength-to-weight ratio

Ability to resist corrosion:

Aluminum has a good resistance to corrosion. It produces a thin oxide film that establishes and protects the metal from oxidation. Aluminum is highly resistant to weathering. It is corrosion resistant to be attacked by some other acids. The high strength alloys are less resistant to corrosion. The alloys can be secured by various surface treatments or by cladding exposed surface with a thin coating of an aluminum alloy.

High strength-to-weight ratio:

It is also called as specific weight. The unit for specific weight is $\text{N}\cdot \text{m}/\text{kg}$. That is, the material’s strength is divided by its density.

• The tensile strength of pure aluminum is roughly $90\text{MPa}$ and improved to $180\text{MPa}$ by cold working. The heat treatable grades can improve a tensile strength of around $570\text{MPa}$. Aluminum alloys increase in strength without ductility and brittle failures at sub zero temperatures.
• The aluminum has a density of $2.7\times {10}^3\text{kg}/{\text{m}}^3$, which is $35\%$ that of the steel.