Caracterização microestrutural de uma liga do sistema Cu-Al-Mn com memória de forma

Abstract

In this work, the microstructural characterization of an alloy of the Cu-Al-Mn system was carried out. The alloys were oven-worked under ambient atmosphere, heat-treated by homogenization and quenching, specimens were made and then characterized by optical microscopy, x-ray diffraction, and tensile tests. It was noticed that at room temperature the crude alloy presents the phases β, γ and Al8Mn5. After the tempering presented the Autentic phase β, when cooled presented the Martensitic phase indicating the shape memory effect confirming to be an alloy of superelastic characteristics. The drawn sample exhibited martensitic phases and others that were determined with the aid of XRD. In the XRD test, it was possible to determine the alloy phases. In the crude fusion sample, it is possible to identify the phase β of structure L21 and space group Fm3m, phase γ, which presents structure Cu9Al4 and space group P-43mn and a third phase , identified in the form of Al8 Mn5, CCC structure and space group I 43m. In the Temperate sample, it is possible to observe the suppression of the existing phases in the crude melt sample after tempering. The sample shows only the austenitic phase β, structure L21 and space group Fm3m. The drawn sample showed the β phase, the plane γ phase and the orthorhombic γ 'martensitic phase of the AlCu3 structural formula and the P2mm spatial group, which represents one of the two martensitic phases that can be formed in CuAlMn alloys.