Tensile test is a fundamental experiment in material testing. It is used to determine how a material behaves when force is applied to it.
In this test, four different specimens; copper, brass, annealed copper and mild steel is deformed by applying uni-axial force. One end of the specimen is fixed while the other end is being pulled at a constant velocity. The behaviour of the material can be identified from the Force-extension graph above. At first, the graph forms a steep, straight line. This shows that the material behaves elastically and will spring back to its original length when unloaded. At the plastic deformation, material will not return to its original state but instead remain elongated (permanent deformation). Necking occurs after the material reaches the maximum force.
From the Force-extension graph, a stress-strain graph can be obtained. The…show more content… It also has a relatively low elongation and has the lowest Young’s Modulus. From Fig. 1, it is seen that the plastic region is long hence, the specimen is ductile. A longer plastic region means that it takes a longer time to fracture after permanent deformation.
In the case of brass, it has the lowest reduction area and the highest Young’s Modulus. It also has a high percentage of elongation. Hence, we can conclude that brass is a brittle material compared to the other specimens. As seen in Fig. 2, the material fractures right after the maximum force is applied and in Fig. 5, we can see that it has the steepest elastic region. It took a short time for brass to fracture and it made the loudest sound during fracture.
Annealed copper is also a ductile material as it have a long plastic region (see Fig. 3). Annealed copper has a low Young’s Modulus, lowest percentage of elongation and a relatively high percentage of reduction in area. It also has a low yield