Coring micron- and milli-scale holes in metallic glasses

Metallic glasses (MGs) combined with copper cores possess many advantages in precision casting and coring of alloys. In this study, inner holes with different dimensions and complex sectional shapes were fabricated through direct casting and coring in MGs. The MG castings show good surface finish and the cored inner holes exhibit high aspect ratios larger than 80 while holding a tight dimension tolerance. The dimensional deviation was proved to originate mainly from the contraction disagreement between castings and copper cores by comparing their thermal expansion coefficients and simulating the solidification and cooling processes, while other factors may also contribute to it. The results are expected to provide a convenient and economical way in the near net-shape fabrication of inner holes in metallic devices and in the assembly of MG components.

► Inner holes can be fabricated by direct casting and coring in metallic glasses.
► Inner holes exhibit high aspect ratio and hold a tight dimension tolerance.
► Castings can imprint micro-features on mold surface and show good surface finish.
► Deviations originate from the disagreement in thermal expansion coefficients.
► Other factors also contribute to the dimensional deviation.