During Vickers hardness testing, the pyramid indenter point angle is__________________?
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Answer: C. 136°
Explanation
The Vickers hardness test employs a diamond indenter shaped into a square pyramid geometry. The included apex angle between opposite faces of this diamond pyramid measures exactly 136 degrees. This specific angle produces geometrically similar indentation impressions across varied testing loads. Hardness testing evaluates a material resistance to permanent plastic surface deformation. Robert L. Smith and George E. Sandland developed the Vickers test in nineteen twenty four. Indentation diagonals are measured optically under a microscope to calculate the final hardness number.
Vickers testing is widely used in metallurgy because it creates a single continuous hardness scale. The test accommodates very soft materials and extremely hard ceramics by altering test loads. Quality control laboratories rely on Vickers hardness data to verify heat treatment effectiveness. An angle of 40 degrees is far too sharp and would cause excessive penetration splitting. Angles like 122 or 152 degrees do not conform to standard Vickers diamond geometry. Geometric similarity across loads depends strictly on the standard 136 degree pyramid configuration.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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