Millwright Level 1 Practice Exam

As the hardness of a metal increases, what other property tends to increase?

1. Toughness

2. Ductility

3. Brittleness

4. Corrosion resistance

The correct answer is: Brittleness

As the hardness of a metal increases, brittleness tends to increase. Hardness refers to a material's resistance to deformation, typically characterized by its ability to withstand pressure and scratching. However, as metals become harder, their internal structure often changes in a way that reduces their ability to absorb energy before failing. This is where brittleness comes into play; it describes a material's tendency to fracture or break easily without significant deformation. In metallurgy, there is often a trade-off between hardness and other mechanical properties. For instance, tougher materials can absorb more energy and deform without breaking, whereas harder materials that are very resistant to deformation can become more brittle. Therefore, the relationship between increasing hardness and brittleness is significant in understanding the behavior of metals under stress.