Not OK defective part showing cracks (left) and an OK part (right)

Small closure parts of a cosmetic packaging product were analysed by Aludium via chemical composition and metallographic tests.

The Miniaturised Tensile Test (MTT) was applied to obtain the local mechanical properties of the material in real parts with insufficient amount of material available for conventional testing. This test, offered as part of FormPlanet service offering, made it possible to determine the mechanical properties – yield strength, ultimate tensile strength, uniform elongation, total plastic elongation and reduction of cross-sectional area – of both parts with and without cracks from three different areas of the packaging product.

MTT was able to detect deviations on material homogeneity in the closure parts in comparison to the flat rolled material. Non-cracked parts showed a very low strengthening after the drawing process, which is characterized by higher elongation and a compromise between Rp0.2 and Rm values.

These results will allow Aludium to redesign its thermomechanical production process in order to prevent the occurrence of cracks in the closure parts during the forming processes.

Micro-Tensile Tests (MTT) permit to locally assess basic tensile properties as yield stress, ultimate tensile strength, total elongation, reduction of area and uniform elongation. Furthermore, MTT can be used to study strain rate sensitivity in a wide range of temperatures.

These miniaturised testing techniques can be successfully applied when insufficient volume of material is available, for the development of new alloys, for the evaluation of the local mechanical properties of in-service components and as an input data in numerical simulation for advanced material modelling.