Final answer:
The surface area of indentation when performing the Brinell hardness test on an aluminum specimen with a 4.49 mm indentation diameter is 15.86 mm². The force applied, given a Brinell hardness value of 684, is approximately 132,648 N.
Step-by-step explanation:
To determine the surface area of indentation for the Brinell hardness test on an aluminum specimen:
- The indentation diameter is 4.49 mm.
- To find the surface area of a circle, use the formula A = π * (d/2)^2, where d is the diameter.
- The calculated area A = π * (4.49 mm / 2)^2 ≈ 15.86 mm².
To find the force applied in the Brinell hardness test:
- The Brinell hardness value (HB) is 684.
- Brinell Hardness is defined as HB = 2P / (πD( D - √(D^2 - d^2) )), where P is the force, D is the diameter of the indenter, and d is the diameter of the indentation.
- Rearrange to solve for P: P = HB * (πD( D - √(D^2 - d^2) )) / 2.
- Put in the respective values: P = 684 * (π * 12 mm * (12 mm - √(12^2 mm² - 4.49^2 mm²))) / 2
- The calculated force P is approximately 132,648 N.
Therefore, the surface area of indentation in mm² is 15.86 and the force applied in N is 132,648.