Characterization, mechanical properties and dimensional accuracy of a Zr-based bulk metallic glass manufactured via laser powder-bed fusion. (1st February 2021)

• Record Type: Journal Article
• Authors: Sohrabi, Navid; Jhabvala, Jamasp; Kurtuldu, Güven; Stoica, Mihai; Parrilli, Annapaola; Berns, Siddartha; Polatidis, Efthymios; Van Petegem, Steven; Hugon, Sylvain; Neels, Antonia; Löffler, Jörg F.; Logé, Roland E.
• Is Part Of: Materials & design. Volume 199(2021)
• Publication Date: 2021-02-01
• Subjects: Additive manufacturing -- Bulk metallic glass -- Laser powder-bed fusion -- Nano-crystallization -- Precision manufacturing -- Selective laser melting; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2020.109400
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Bulk metallic glasses (BMGs) are high-strength, highly elastic materials due to their disordered atomic structure. Because BMGs require sufficiently high cooling rates to bypass crystallization, laser-based additive manufacturing (AM) methods have recently been employed for the fabrication of BMGs. In this study, we present an optimized Laser Powder-Bed Fusion (LPBF) process on a Zr-based BMG (Zr59.3 Cu28.8 Al10.4 Nb1.5, in at.%), with a focus on characterization, mechanical properties, and dimensional accuracy. A volumetric density of 99.82% was achieved. Although the sample was qualified as amorphous via laboratory X-ray diffraction experiments, a more meticulous study using synchrotron radiation revealed nanocrystals in the heat-affected zones (HAZs) of the melt pool. Fast differential scanning calorimetry (FDSC) and numerical simulations were then employed to illustrate the mechanism of crystallization. The LPBF-processed alloy revealed excellent mechanical properties, such as high hardness, wear resistance, compressive strength, and flexural strength. Apart from vein-like patterns, the fracture surfaces of the compression test samples showed liquid-like features, which indicate a significant local temperature increase during fracture. The dimensional accuracy was assessed with a benchmark exhibiting complex geometrical features and reached at least 40 μm. The results indicate that LPBF processing is a promising route for the manufacturing of BMGs for various applications. Graphical abstract: Unlabelled Image Highlights: Advanced characterization is required to detect nanocrystals formed during the Laser powder-bed fusion process Results of finite element simulation and fast differential scanning calorimetry unveil the mechanism of crystallization Despite the presence of nanocrystals in the Zr-based BMG, excellent mechanical properties are achieved Using optimized parameters, a benchmark with complex features is fabricated with excellent geometrical accuracy