With the development of additive manufacturing (AM) technology, scientists noticed that both the high cooling rate and the little-scale molten pool properties in this technology might be the way to fabricate Bulk Metallic Glasses (BMGs). By well controlling the parameters according to the energy density equation, molten pool in Laser Powder Bed Fusion (LPBF) process can be stacked together, forming the final products. Although LPBF has such excellent characteristics for manufacturing BMGs theoretically, two major issues still exist. First, the densification of printing objects will be affected by the related parameters. Specifically, the laser power (P), scanning speed (v), hatch distance (h), and layer thickness (t), all these four parameters comprise the energy density, which will determine the behavior of the molten pool. Hence, finding the optimized parameters to get the most appropriate arrangements of the molten pool inside the specimen is the most important factor for densification. Second, the Heat Affected Zone (HAZ), caused by the heat transfer around the molten pool, would reheat the printed amorphous alloy and cross Tg, resulting in crystallization.

To overcome the challenges mentioned above, repetitive scanning was introduced to this research. For the first scan, the lower energy melted the metal powders, forming the porous structure and supplying a method for increasing the heat conduction and thus reducing the HAZ’s influence. After that, a higher laser energy density was introduced, melting the porous structure completely.

In summary, this research will focus on the difference between the two scanning strategies (the single and the repetitive scanning strategy) in terms of densification and microstructure. Phase identification was conducted through XRD, DSC, and SEM/EDS. Next, molten pool morphology and HAZ were observed through SEM/BEI. Finally, the mechanical property tests of different positions/microstructures inside and outside the molten pool were conducted by Nanoindenter.