Local Hardness Variation of Ti50Cu32Ni15Sn3 Processed by Laser Beam Melting (LBM)

Abstract

Amorphous metals which are synonymously called metallic glasses form a rather young group of engineering materials. Compared to crystalline metals they offer unique combinations of properties: tensile strength, hardness, elastic strain, resistance against corrosion and abrasive wear are rather high. In order to minimize crystal growth, rapid solidification from the liquid phase is required. High cooling rates are a characteristic property of the additive manufacturing technology Laser Beam Melting in Powder Bed (LBM). This paper shows first results of processing Ti50Cu32Ni15Sn3 by LBM. Unlike many other alloys with high glass forming ability, it does not contain costly rare earth elements. No literature is known to the authors about LBM of this material. Because relative density close to 100 % is a prerequisite for producing parts with high mechanical performance, a parameter study was conducted varying scan speed, hatch distance and laser power in wide ranges. The obtained samples are characterized by metallographic sections, hardness measurements and X-ray diffraction. Apart from reaching high relative densities, a wide variation in Vickers hardness over the length of samples was found. It corresponds to the locally different thermodynamic conditions. Apart from introducing a new material with promising properties to the manufacturing technology of LBM, this might open up a new approach to modify mechanical material properties in a single work piece made from uniform powder by adapting LBM process parameters. Both the range of applications for LBM as well as the range of geometries producible from amorphous metals might be expanded.