NOMATEN HYBRID-SEMINAR January 8: Enhancing the mechanical properties of an additive manufactured Zr-based bulk metallic glass

NOMATEN HYBRID-SEMINAR

online: https://meet.goto.com/NCBJmeetings/nomaten-seminar
In-person: NOMATEN seminar room

Tuesday, JANUARY 8^th  2025 13:00 CET

Enhancing the mechanical properties of an additive manufactured Zr-based bulk metallic glass

Prof. Jamie J. Kruzic
University of New South Wales (UNSW Sydney), Sydney NSW 2052, Australia.

Abstract:

Laser powder bed fusion (LPBF) enables the fabrication of large-dimensioned bulk metallic glass (BMG) components; however, we are only just learning how to control the LPBF process to obtain specific mechanical properties. LPBF was used to produce dense and fully amorphous Zr59.3Cu28.8Nb1.5Al10.4 BMG samples from two different starting powders. One powder had a relatively finer particle size range of 10-45 μm and the other had a relatively coarser particle size range of 25-63 μm. Fully amorphous samples were achieved for both powders within a large processing window of laser power and scanning speed combinations. When the LPBF volumetric energy density was raised above ~30-33 J/mm3, high relative density (> 99%) was maintained along with devitrification and embrittlement. Low LPBF energy densities below ~20 J/mm3 produced low relative density (< 99%) and fully amorphous samples. Strength and hardness generally increased with increasing LPBF energy density while the relaxation enthalpy, ductility, and fracture toughness decreased. Furthermore, the coarser powder had four times lower oxygen content and gave better glass forming ability, compression ductility up to 6% plastic strain, and fracture toughness up to ~38 MPa√m. These findings demonstrate that it is possible to tailor the structure and mechanical properties of BMGs by tuning the LPBF process parameters within a wide processing window and by controlling the feedstock powder oxygen content.

Bio:

Prof. Jamie Kruzic joined UNSW Sydney as a professor of mechanical and manufacturing engineering in 2016, and he held the position of Deputy head of school from 2017 to 2023. His research focuses on the mechanical behaviour of a wide range of engineering materials (metals, ceramics, intermetallics, composites), biomaterials, and biological tissues, with emphasis on the mechanisms of fracture, fatigue, and deformation. Professor Kruzic is the recipient of a Friedrich Wilheim Bessel Research Award of the Alexander von Humboldt Foundation. Through this program, he joined the chair of the metallic materials of TU-Berlin for a few months research stay within the group of prof. Gallino.