A new experimental method to develop multicomponent amorphous alloys

• Grant number: 14/25034-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2015
• End date: January 31, 2016
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Piter Gargarella
• Grantee: Leonardo Luiz de Oliveira Medrano
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/05987-8 - Processing and characterization of amorphous, metastable and nano-structured metallic alloys, AP.TEM

Abstract

The theoretical or semi-empiric methods to select new bulk metallic glasses in multicomponent systems (more than 3 elements) exhibit a lack of precision because the high complexity of these systems, which difficults the calculations. By another hand, the experimental methods (usually a casting method) demand intensive work, time and waste of materials because the alloys need to be prepared one by one. Considering this, it is important to develop faster and more efficient methods to select new bulk metallic glasses in multicomponent systems. A method used to investigate the effect of compositional changes in the phase formation and properties of alloys is laser cladding, by which powder is melted using a laser beam and deposited on a substrate. This method allows obtaining coatings with an amorphous structure since high cooling rates are imposed and allows varying the track composition by using multiple powder feeders. Multicomponent systems can be investigated with the preparation of only a few number of tracks with varied composition. This method is faster and may allow detecting compositional ranges with higher glass forming ability with relative good precision. This project intends to evaluate the use of the laser cladding method to obtain new bulk metallic glass compositions in the Al-Co-Zr system by varying the composition of the deposited material. Tracks with composition varying in the range Co72Zr28)1-x(Zr69.5Al30.5)x (%at.) com x = 0 - 1 were produced by the laser cladding method using powder of Co72Zr28 e Zr69.5Al30.5 (%at.), which were fabricated by mechanical alloying. In this project, the tracks will be characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and microhardness. It will be calculated the amorphization criterion »+”h1/2 for the Al-Co-Zr system in order to compare with the experimental results.