Teach lesson
Hardness Measurement: indentation evidence in Materials
Students use the Materials remote lab to compare Vickers and Brinell hardness evidence, connect indentation size with hardness, and distinguish surface hardness from toughness or tensile strength.
Learning Outcomes
Explain hardness as resistance to localized plastic indentation.
Compare Vickers and Brinell methods at an introductory level.
Use indentation-image evidence to reason about relative hardness.
Separate hardness claims from toughness and tensile-strength claims.
Identify method/load information needed for a defensible hardness comparison.
Student activity preview
Activity Content
Preview only. In a class session, students can fill in responses and submit their work to the teacher.
1. What hardness means
14 min
Hardness is a material's resistance to localized plastic deformation. In indentation hardness tests, a shaped indenter is pressed into the surface under a known load. The size of the indentation is then used to infer hardness.
Hardness measurement in Materials
Hardness tests probe the surface near the indentation. They do not by themselves prove impact toughness or tensile ductility.
Two common indentation methods are:
- Vickers hardness (HV): a diamond pyramid indenter; useful over a wide range of loads.
- Brinell hardness (HB): a ball indenter; often leaves a larger circular impression.
For the same method and load, a smaller indentation generally means a harder surface. Vickers hardness is derived from the applied load and the indentation diagonal. Brinell hardness is derived from the applied load and the indentation diameter. Comparing different methods or loads requires caution because the geometry and scale change.
Define hardness for this activity, and explain why hardness is not the same as toughness.
For the same hardness method and load, what does a smaller indentation usually indicate?
2. Run hardness observations
24 min
Use the Materials route for Hardness measure. Start with the demo-safe route steel / 1.4301 / as delivered / HV1. If your access allows more routes, compare a second treatment or method while keeping the comparison controlled.
Example indentation image
Record what the image actually supports: indentation shape, relative size, method, load label, and visibility.
Open Materials and run a hardness measurement
Open Materials from this activity.
Choose Hardness measure.
Select steel / 1.4301 / as delivered / HV1 for the first run.
Observe the indentation image and any hardness value or method label shown by the interface.
Record the method, load/submethod, visible indentation shape, value if visible, and confidence.
If your session allows a second route, compare only one changed factor at a time: method/load, treatment, or material.
Hardness evidence table
Use one row per hardness route. The first row is enough if your session only exposes the demo-safe HV1 route. For a fair comparison, keep method/load the same when comparing materials or treatments. If you change method/load, explain that the comparison is method-sensitive.
| Material / alloy / treatment | Method/load | Hardness value if visible | Diagonal/diameter if visible | Unit or hardness scale | Indentation observation | Fair comparison? | Confidence and reason |
|---|---|---|---|---|---|---|---|
If you compare two hardness rows, what changed and what stayed the same? Explain why that matters.
3. Interpret indentation evidence
22 min
Use your table to make the strongest relative-hardness statement you can. Include the method/load and at least one visual or numeric evidence detail.
Why is it risky to say that an HV1 result and an HB2.5 result are directly comparable without further method discussion?
What can your hardness result say about the material, and what can it not say without additional tensile or impact tests?
4. Hardness report
10 min
Write a short hardness-measurement report paragraph. Include specimen route, method/load, hardness evidence, a controlled comparison if you made one, and a clear limit on what hardness can prove.