Materials Letters ( IF 3.204 ) Pub Date : 2020-01-18 , DOI: 10.1016/j.matlet.2020.127376 Linlin Zhai; Yunzhuo Lu; Lu Wang; Xing Lu
Laser additive manufacturing (LAM) technology presents a great chance to break through the size limitation and realize the wide applications of bulk metallic glasses (BMGs). However, one of the inherent problems associated with this technical route is the unavoidable hidden pore defects, which is detrimental to the mechanical properties of the BMGs. In the present study, a comprehensive investigation of hidden pore defects in a typical model BMG Zr51Ti5Cu25Ni10Al9 fabricated by LAM is performed by using the computed tomography (CT) technology. The overall porosity of the LAMed BMG samples is found to be increased with increasing laser power. However, the variation trends of the proportions for different-size pores are not the same. Specifically, the proportions of larger pores are increased with the consumption of small ones as the laser power increasing. This opposite evolution trends of pores with the increasing laser power is analyzed from the Marangoni effect in the molten pool flow.