Processing a glass-forming Zr-based alloy by selective laser melting

Compact specimens were produced by selective laser melting (SLM) from glass-forming Zr52.5Cu17.9Ni14.6Al10Ti5 powder. Below a critical energy density of E-crit = 15 J/mm(3) fully glassy samples were obtained. When the energy density is higher, the metastable big cube phase, stabilized by oxygen, precipitates next to other crystalline phases. We introduce density contour maps to identify the process window, which allows obtaining fully glassy samples with a high relative density of up to 98.5%. The systematic parameter variation illustrates the importance of laser power for obtaining dense SLM parts. Moreover, the distribution of pores in the present alloy is rather sensitive to the scanning strategy. The compressive strength of the SLM samples is comparable to values measured for as-cast glasses and even a distinct plastic strain is found. Finally, scaffolds were produced and high-energy X-ray diffraction proves that they are fully glassy irrespective of differences in the local cooling rates. Our experiments contribute to better understanding the behaviour of Zr52.5Cu17.9Ni14.6Al10Ti5 during SLM and for making glass-forming alloys progressively more accessible to laser-based additive manufacturing in order to overcome the intrinsic size limitation of bulk metallic glasses. (C) 2017 Elsevier Ltd. All rights reserved.