Question

It is desired to evaluate the tensile properties of an aluminum alloy. A tensile test is performed using a standard cylindrical tensile specimen with a diameter of 12.8 mm and a gauge length of 50.800 mm. The gage length and final diameter of the sample are measured after the sample is removed from the testing machine. The gage length and the diameter of the necked region after the specimen was removed from the testing machine are 60 mm and 9 mm, respectively. The following data was generated during the tests. 7. Use the information in the following table and the load – elongation curve to calculate:

A. Calculate the engineering stress at rupture (point 16)

B. Calculate the engineering strain at rupture (point 16)

C. Calculate the true strain at the maximum load (point 12).

D. Calculate the true stress at the maximum load (point 12).

Using points 8 and 12 in the following table, determine the values of the strength coefficient and the strain hardening exponent.

A. Strength Coefficient (K)

B. Strain Hardening Exponent (n)

Point on Curve, length (mm), load (N)

1 50.800 0

2 50.851 7,330

3 50.902 15,100

4 50.952 23,100

5 51.003 30,400

6 51.054 34,400

7 51.308 38,400

8 51.816 41,300

9 52.832 44,800

10 53.848 46,200

11 54.864 47,300

12 55.880 47,500

13 56.896 46,100

14 57.658 44,800

15 58.420 42,600

16 59.182 36,400

Answer 1