First attempt to print Co-based alloys with high glass forming ability by selective laser melting

Amorphous metals have been of interest to researchers since the 1960 s of the twentieth century. In recent years, interest has been focused on the development of amorphous metals using selective laser melting (SLM) technology, because it guarantees very high cooling rates and allows the production of a theoretically unlimited size of elements. However, no studies have considered the development of SLM alloys with a high glass ability based on cobalt. This work offers one of the first investigations into the possibility of developing amorphous samples from Co 42 B 26.5 Fe 20 Ta 5.5 Si 5 Cu 1 using SLM technology. The study involves two-stage experimental parameters testing and testing obtained samples by optical and scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction analyzes, energy dispersive spectroscopy by TEM mapping, nanoindentation, and microhardness testing. This paper has shown that the optimal energy density (ED) window for printing Co 42 B 26.5 Fe 20 Ta 5.5 Si 5 Cu 1 is between 41 and 50 J/mm 3 and samples with the best structure form carried out experiment were developed with a laser power of 75 W and a scanning speed of 800 mm/s (ED 48.7 J/mm 3 ). However, the Rietveld analysis of the crystal phase in his sample points out the 54% crystal phase (Co 5 Si 2 B and TaB 2 ) in this sample, which makes it a bulk metallic glass composite. • The first Co-based bulk metallic glass composite developed by selective laser melting was produced. • The phases detected in the bulk samples of Co 42 B 26.5 Fe 20 Ta 5.5 Si 5 Cu 1 were Co 5 Si 2 B and TaB 2 . • The developed structure exhibits very high hardness (around 17.7 GPa). • The best sets of parameters were established for further research (laser power75W, scanning speed 800 mm/s).