Caracterização termomecânica de estruturas celulares de liga com memória de forma Cu-Al-Mn obtidas por fundição de precisão.

Abstract

For many years, cellular structures, such as honeycombs, are being studied because these arrays have numerous possibilities of structural applications, such as impact load damping. Most materials with cellular structures are made of aluminum, and are widely used in the naval and aviation industries. However, aluminum cellular structures have the disadvantage that they can accumulate permanent deformations (plastic regime), irreversible even when subjected to heating. In this context, the objective of, this research is the fabrication and thermomechanical characterization of cellular structures of a Cu-Al-Mn Shape Memory Alloy (SMA) produced by precision casting with four different cell geometries (honeycomb, reentrant, diamond and “S”- structure) with two thicknesses (1 mm and 0.5 mm). The obtained results showed that the cellular structures presented phase transformation characteristic of the Shape Memory Effect (SME) phenomenon with deformation at room temperature followed by heating. The isothermal mechanical compression tests showed the functional behavior related to the EMF and Superelasticity (SE) phenomena. It was also found that 0.5 mm thick cell structures require lower levels of maximum force at the end of each 5% compression cycle, around 1/3 to 1/10, compared to 1 mm thicknesses. Finally, almost all cell structures produced showed good deformability and can be used as shock absorbers due to their behavior verified in compression tests.