2.4. Hardness

Try these first

1. 1.

   What does hardness refer to in materials?

   Hint

   Think about how materials react to being scratched.

2. 2.

   Name one method to measure hardness.

   Hint

   One method measures indentation size, the other measures depth.

3. 3.

   What is hardness in the context of materials?

   Hint

   Think about how you would describe a very hard material.

4. 4.

   True or False: The Rockwell hardness test measures the diameter of an indentation.

   • True
   • False

   Hint

   Think about which measurement gives a better indication of hardness.

5. 5.

   You need to select an aluminum alloy for a structure that will face high wear and tear. Explain how you would determine the required hardness and which tests you might choose.

   Hint

   Consider both the application’s environment and expected stress.

6. 6.

   Given two aluminum alloys, one with a Brinell hardness of 60 HB and another with 120 HB, explain the impact this difference in hardness could have on their applications.

   Hint

   Think about the environments where each might be used.