Partial crystallization in a Zr-based bulk metallic glass in selective laser melting

Metals and alloys in amorphous state are promising for the use as structural functional materials due to their superior properties related absence of such defects grain boundaries dislocations. Obtaining requires quenching from liquid with a high cooling rate. In conventional technologies, this is reason considerable size limitation hindering application alloys. Additive manufacturing (AM) free limitation. The so-called bulk metallic glass (BMG) have extremely low critical rates can be used AM. Recent studies on AM Zr-based BMGs by selective laser melting (SLM) has proved possibility attaining revealed partial crystallization principal drawback process. present work aims analyze conditions attempts control it optimizing process parameters. A comprehensive parametric analysis accomplished single-track SLM experiments BMG alloy Vit 106. observed microstructures temperature fields thermal cycles estimated an analytic heat-transfer model laser-impact zone. cross section track, central bright domain identified remelted An annular darker zone encircles fits experimentally obtained dependencies versus power scanning speed indicates that 43 ± 2% incident energy transferred into substrate energy. losses reflection radiation material evaporation. Primary crystalline inclusions existing before processing dissolve at melting. mean rate up 4 orders magnitude greater than Therefore, homogeneous nucleation not expected. Nevertheless, theoretically times sufficient crystal growth heat-affected where primary nuclei completely dissolved.