Experimental prediction of lead failure under tensile load using scanning contact potentiometry technique
The issue of accurate identifying in advance structural nonhomogeneities of metals is one of the main factors in improving the manufacturing efficiency and safety during service. This paper illustrates the conventional uni-axial tensile test that is carried out on the diffuse and localized necking stages of dog-bone shape lead specimen. The scanning contact potentiometry method was used to locate the rupture zone. Infrared radiation was used to heat the specimen up to 40°C, in order to excite structural nonhomogeneities in the bulk of the tested specimen. It was found that the infrared radiation increases the predictable nonhomogeneity zone. A ductile rupture occurs in the same nonhomogeneity zone that was previously exactly identified using the scanning contact potentiometry method. The formed diffused necking was observed to initiate from the right where the rupture spread diagonally, at an angle of 70° between the tensile axis and the rupture plane. However, the angle between the tensile axis and the hexagonal singular reflex plane was 69°, which was slightly different from the rupture angle. Both results of the rupture angles of the tensile test and the SCP are relatively matching and diverse from the theoretical calculations. The results shown in this work highlight the importance and the efficiency of the experimental SCP method in prediction of the material failure behaviour.