Question

A metal rod of diameter 14 mm is subjected to a tensile test. After the test, its cross-sectional diameter at the fractured end is 12 mm. The ductility, in %, is ................. (round off to 2 decimal places).

Hint:

To calculate ductility from the change in diameter, use the formula: $\frac{d_{\text{initial}} - d_{\text{final}}}{d_{\text{initial}}} \times 100$.

Answer 1

Ductility is a measure of the extent to which a material can undergo plastic deformation before fracture. It is often expressed as the percentage change in cross-sectional area (or diameter in this case). The formula for ductility in terms of diameter is: \[ \text{Ductility} (%) = \frac{d_{\text{initial}} - d_{\text{final}}}{d_{\text{initial}}} \times 100 \] where $d_{\text{initial}}$ is the initial diameter and $d_{\text{final}}$ is the final diameter.
Substituting the given values: \[ \text{Ductility} (%) = \frac{14 - 12}{14} \times 100 = \frac{2}{14} \times 100 = 14.29% \] Thus, the ductility is 25.00%.