Selective laser melting of Zr-based bulk metallic glasses: Processing, microstructure and mechanical properties. (15th December 2016)

• Record Type: Journal Article
• Authors: Li, X.P.; Roberts, M.P.; O'Keeffe, S.; Sercombe, T.B.
• Is Part Of: Materials & design. Volume 112(2016)
• Page Start: 217
• Page End: 226
• Publication Date: 2016-12-15
• Subjects: Bulk metallic glasses -- Selective laser melting -- Crystallisation -- Microstructure -- Mechanical properties; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.09.071
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: This study shows that large scale, complex and fully dense crack-free Zr-based bulk metallic glasses (BMGs) with high hardness, high compressive strength and a small amount of ductility can be achieved using selective laser melting (SLM). The results show that higher laser energy density leads to severe crystallisation while lower laser energy density tends to result in the formation of a fully amorphous material. By investigating the chemical distribution of the melt pool, the underlying reason for this behaviour was attributed to the chemical inhomogeneity caused by the melt flow triggered elemental segregation at high energy densities. In addition, the chemical homogeneity can be improved in some cases through the use of a multiple pass scanning strategy. The underlying mechanism is that multiple scans can result in an averaging of the melt flow within the melt pool and therefore a more homogenous distribution of the elements. More importantly, the phase formation, microstructure and mechanical properties of the SLM-fabricated Zr-based BMGs can be effectively tailored by controlling the SLM processing parameters. This provides a novel and promising route to the fabrication of large scale BMGs with complex geometry and desirable mechanical properties. Graphical abstract: Highlights: Large scale, complex and fully dense crack-free Zr-based BMGs can be achieved using SLM. The fabricated BMGs have high hardness, high compressive strength and a small amount of ductility. The phase formation, microstructure and mechanical properties of the BMGs can be tailored by controlling SLM parameters. Chemical homogeneity within the melt pool plays a critical role in determining the amorphous nature of the fabricated BMGs. Multiple scans can result in an averaging of the melt pool and therefore benefit the formation of amorphous phase.