Processamento, microestrutura e propriedades de componentes produzidos a partir de pós descartados da liga AlSi10Mg

Abstract

Out-of-spec aluminum powders, usually discarded, represent an underutilized resource. Alternative consolidation routes make powder reuse a promising and environmentally sustainable solution for the AlSi10Mg alloy. The methodology of this work addresses the uniaxial compaction of powders under loads between 30 and 100 kN, followed by remelting and rapid solidification by suction casting. The main objective is to verify the possibility of producing components with mechanical and tribological properties similar or superior to those obtained by conventional routes. The results show that the adopted route produces parts with extremely low porosity (≤0.2%) and refined dendritic microstructures (spacings between 2.4 and 4.6 µm). Microstructural refinement is mainly controlled by the cooling rate and the compaction load. Intermediate loads (50–80 kN) enhance densification and refinement, resulting in low porosity, whereas higher load (100 kN) proves detrimental, leading to increased porosity (3,6%) and reduced microhardness (87 HV) due to limited penetration of the molten metal. Samples with more refined microstructures achieve compressive strength above 500 MPa and Vickers microhardness values exceeding 100 HV, values that significantly surpass by conventional casting (60–80 HV). In wear tests, an inverse correlation between hardness and wear rate has been observed. The densest and most refined samples (50 kN/3 mm) exhibit wear rates of 2.3 × 10⁻⁴ mm³/N·m, comparable to components produced by Laser Powder Bed Fusion. Even under abrasive conditions, although mass loss was higher, the influence of microstructural refinement remains evident. The combination of compaction and suction casting is thus confirmed as an efficient upcycling strategy for AlSi10Mg, converting powder waste into high-performance components for automotive and aerospace applications, particularly thin-walled parts.