Introduction:
To determine the properties of tensile test, Aluminum alloy, A6061 is used. In the figure you can see the Baldwin, the universal testing machine, through which tensile test is performed. Tensile test has the four properties, the YS that is the yield test, MOE, it is the modules of elasticity, UTS, it is the ultimate strength of tensile and RS, the rupture stress. These all four categories are created or determined throughout or during the lab period, by using the plot.
Figure (1) the universal testing machine “Baldwin” is shown in the image.
Experimental Procedures:
- By measuring the width and depth of the sample, the cross sectional area of the sample can be determines. The formula used for the cross sectional area, of Aluminum is:
A (area) = width (W) × depth (D).
- In the Baldwin universal testing machine, the aluminum rod is fixed by the instructor. The rod is fixed so that the sensor should be fixed carefully, so that damage cannot be take place. In the following figure (2) the sample of A6061 is showed, before the load applied on it.
- The data is collected and the load is applied in the sample of A6061, until the failure. The process is done on the designed computer and in the lab. The data is given have the strain and stress, the data can also be used as the initial length.
- Before starting the experiment, the student required to have or need to calculate the width and depth of the sample.
- Through dividing the force (IB) by the cross sectional area, the stress is given.
- The strain (e) can be given by the change in the length, which is when divided by the original length.
- During the lab, the plot can be automatically done.
Figure (2), the sample of the Baldwin universal testing machine.
Results:
The whole experiment of Aluminum alloy A6061 is showed in the graph. In the following plot, the values of MOE, YS, UTS are written, which are defined as graphically and numerically.
| Property | Measured Value | Text Book Values |
| YS | 19500 + 200 psi | 47,000 psi |
| UTS | 24200 + 200 psi | 45,500 psi |
| MOE | 6.1 x 106 + 0.1 x 106 | 10 x 10^6 |
Graph 1 – Stress vs. Strain for Untreated Al 6061 Alloy
Discussion:
The values that are given theoretically have the big difference between the text book values and the values that have obtained by the experiment. In the textbook the value given is 10 x 10^6, but through the experiment the value get is (6.1 + 0.1) x 106. The YS also have the different value, in the text book it 47,000 psi, however, the value get is 19500 + 200 psi. The values are slightly different from the value of the book. There is also difference in the UTS; the textbook value is 45,500 psi while the value determined is 24200 + 200 psi.
There is the difference between the values of the book and the values determined. The theoretical and experimental values are different, the values that is written in the literature, are connected to the treated aluminum, so the values are stronger than the untreated aluminum.