Innovative Aluminum Based Metallic Glass Particle Reinforced MMCs Produced by Gas Pressure Infiltration

Abstract

Over the last years, new alloys were developed to create metallic glasses showing high crystallization temperatures. Such metallic glasses generally can be embedded into other materials when processing temperatures are lower than crystallization temperatures. As recent studies show, feasible crystallization temperatures may exceed the melting point of common metals and fabrication of metallic glass particle reinforced MMCs is now not only possible by powder metallurgical methods but also by processes using melt infiltration. Hence, these metallic glasses offer a high potential for use as reinforcements in a lightweight metal matrix such as aluminum: By incorporation of metallic glass structures into a ductile matrix, it is possible to utilize its outstanding advantages like high strength and elastic strain limit while circumventing its negative properties like brittleness.The particle reinforced composites in this contribution were produced by gas pressure infiltration. This process includes melt infiltration of a particle filled mold using pressurized gas. To keep a sufficient separation between processing temperature and crystallization temperature, the metallic glass Ni60Nb20Ta20 (Tx = 721 °C) and the eutectic aluminum alloy AlSi12 with a low melting point (Tm = 580 °C) as matrix metal were selected for process. After infiltration, the fabricated MMCs were investigated by micro computed tomography (µCT) to analyze the particle distribution within the composite. Furthermore, mechanical tests and elastic analysis using ultrasound spectroscopy were performed to classify its properties.