Estudo de uma liga superelástica de CuAlMn : influência do reprocessamento por fundição de precisão rápida na fabricação de estruturas celulares

Abstract

Shape Memory Alloys (SMA) based on CuAlMn are alternatives to NiTi SMAs due to their lower cost, higher ductility, cold workability, and potential for diverse industrial applications. A direct application of superelastic CuAlMn SMAs is in cellular structures, which exhibit excellent energy absorption capacity and functional performance. These materials have attracted significant interest across various sectors, including automotive, transportation, naval, aerospace, and sports industries. Additionally, rapid precision casting is a modern and efficient alternative for manufacturing complex SMA components, enabling high precision, material reutilization, and satisfactory mechanical performance.In this context, the main objective of this work is to study a superelastic CuAlMn SMA, analyzing its reprocessing and the fabrication of cellular structures with Diamond and S geometries using the rapid precision casting technique. The CuAlMn SMA was manufactured in an open induction furnace without a protective atmosphere. The results showed that reprocessing CuAlMn SMA through rapid precision casting slightly altered the phase transformation and mechanical properties of the alloy. All fabricated components exhibited superelasticity at room temperature. Compression tests demonstrated that the performance of cellular structures is highly dependent on relative density and unit cell geometry. Structures with higher relative density required greater force levels to achieve a specific strain. The dissipated energy varied according to the test temperature, ranging from 0.14782 MJ/m³ to 0.75014 MJ/m³ for Diamond geometry structures and from 0.04261 MJ/m³ to 0.21135 MJ/m³ for S geometry structures.Furthermore, CuAlMn SMA cellular structures exhibited lower residual strains and force levels approximately 10 times higher at a maximum strain of 5% when compared to aluminum cellular structures. Thus, it was demonstrated that rapid precision casting is a viable technique for reprocessing CuAlMn SMAs, enabling the production of mechanical components with satisfactory mechanical properties while maintaining the desirable characteristics of CuAlMn SMAs.