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The GeniCore Upgraded Field Assisted Sintering Technology U-FAST was applied to the sintering of a commercial Zr-based bulk metallic glass powder AMZ4. The XRD, SEM and DSC analysis of the sintered compacts showed the benefit of the U-FAST method as an enabler for the production of fully amorphous samples with 100% relative density when sintering at 420 °C/480 s (693 K/480 s) and 440 °C/ 60 s (713 K/480 s). The hardness values for fully amorphous samples, over HV1 519, surpass cast materials and 1625 MPa compressive strengths are comparable to commercial cast products. The advantage of the U-FAST technology in this work is attributed to the high heating and cooling rates inherent to ultra-short pulses, which allow to maintain metastable structures and achieve better temperature control during the process. Increasing sintering temperature and time led to the crystallization of the materials. The geometry and material of the dies and punch determine the thermal inertia and pressure distribution inside the compacts, thus affecting the properties of the near net shape NNS compacts made using the U-FAST device.

A new powder production method has been developed to speed up the search for novel alloys for additive manufacturing. The technique involves an ultrasonically agitated cold crucible installed at the top of a 20 kHz ultrasonic sonotrode. The material is melted with an electric arc and undergoes pulverization with standing wave vibrations. Several different alloys in various forms, including noble and metallic glass alloys, were chosen to test the process. The atomized particles showed exceptional sphericity, while powder output suitable for additive manufacturing reached up to 60%. The AMZ4 metallic glass powder remained amorphous below the 50 μm fraction, while tungsten addition led to crystallization in each fraction. Minor contamination and high Mn and Zn evaporation, especially in the finest particles, was observed in atomized powders. The innovative ultrasonic atomization method appears as a promising tool for material scientists to develop powders with tailored chemical composition, size and structure.

Ti-Nb alloys were in-situ fabricated by selective laser melting (SLM) to study the effect of Nb content on their phase transformation, microstructure evolution, mechanical properties and in vitro apatite-forming capability. Results show that α' martensite and β (Ti, Nb) phase are obtained in SLM-processed Ti-Nb alloys. The increase of Nb content results in the increase of β phase amount but decrease of β grain dimension. The former effect is due to the suppression of martensitic transformation and strengthening of solid solution behavior, while the latter phenomenon can be attributed to the increase of heterogeneous nucleation sites. The Ti-25Nb alloy possesses the lowest modulus of 18.7±1.4GPa due to the maximum content of β phase. The SLM-processed Ti-45Nb alloy exhibits superior strength of 1030±40MPa and microhardness of 356±7HV0.1, which is 97.32% and 52.53% higher than cast ones, respectively. The in vitro apatite-forming capability of Ti-25Nb alloy is the most superior compared to other Ti-Nb alloys. It demonstrates that β phase has the ability to induce apatite formation. The research shows that SLM could be used for in-situ fabrication of Ti-Nb bone implants with tailored mechanical and biomedical properties by adjusting Nb addition. Keywords: Ti-Nb alloy, Selective laser melting, Nb content, Mechanical property, In vitro apatite-forming capability