Estudo da influência de pentóxido de nióbio nas propriedades de uma liga de alumínio produzida por metalurgia do pó

Abstract

Aluminum and its alloys are one of the most versatile, economical and attractive metallic materials on the market due to their characteristics and their wide range of applications, ranging from decorative parts to the construction of automobiles, ships and aircraft. Its alloys consist of an aluminum matrix and other elements responsible for providing new properties or improving existing ones. In addition, another metal with a wide variety of applications, both industrial and commercial, is niobium, which is still little explored in Brazilian soil, since Brazil holds more than 90% of the world's reserves of this material. Just as aluminum has its alloys, niobium also has variations in composition, the so-called oxides of niobium, and niobium pentoxide, also known as Nb 2 O 5 , is one of the most produced and commercialized that exists. Thus, the present work aims to combine an aluminum alloy powder with a niobium pentoxide powder, in proportions of 5%, 10% and 50% by %weight, through powder metallurgy techniques. In addition, the work seeks to perform physical (linear shrinkage, mass variation and porosity), mechanical (hardness), microstructural (optical and scanning electron microscopy and X-ray diffraction) and chemical (X-ray fluorescence) characterizations of the mixtures, evaluating the influence of niobium pentoxide on the general properties of the aluminum alloy. The results showed that there was no standardization in the linear shrinkage data. Furthermore, it was noted that the higher the proportions of niobium pentoxide, the higher the percentages of mass variation and porosity obtained, indicating the incomplete elimination of internal gases produced during sintering. The hardness of the combination went from an average of 29.31 HRA in the alloy with 0% Nb 2 O 5 to 82.40 HRA in the mixture with 50% Nb 2 O 5 , an overall increase of approximately 280%. Therefore, the work showed that the addition of different percentages of niobium pentoxide to an aluminum alloy is capable of improving specific properties, such as hardness. However, changes in other properties such as porosity, linear shrinkage and mass variation must be analyzed according to the desired application.