Desenvolvimento de compósitos à base de níquel reforçados com Tac E/Ou Nbc Via Mecanossíntese

Abstract

The constant technological development implies in a growing need of materials with better performances, evaluated under diverse properties, such as greater mechanical resistance, greater resistance to wear, better thermal stability, resistance to corrosion and reduction of weight. With this, engineers, researchers and scientists have sought to improve traditional materials and the development of new composites. In the present work, nickel-based metallic composites were developed, via mechanosynthesis, with reinforcements of tantalum carbide and niobium carbide. The metal powders underwent granulometric analysis to verify the average particle size after milling, sinter validity studies were done for the samples by comparing the densities to green and after sintering, followed by the Rockwell F hardness tests. Samples were studied with 4, 8 and 12 volume percent of the carbides in the metal matrix, varying the milling times of 2, 4 and 6 hours. From the results obtained it was verified that the samples of NT4 obtain better properties with time of grinding of 4 hours and the samples of NT8 and NT12, obtains better dispersion with time of milling of 2 hours. Samples with niobium carbide reinforcement showed little behavior variability as the grinding time was increased to obtain. All these samples had lower density than pure nickel. For the samples reinforced with tantalum carbide and niobium carbide densities were below that of pure nickel. The density of the samples increased as the percentage by volume as well as the milling time increased. There was a slight reduction in the hardness of the samples as the grinding time was increased in all samples, except in the 4 hour NN4 sample which considerably reduced its hardness.