Superplastic gas pressure forming of Zr65Al10Ni10Cu15 metallic glass sheets fabricated by squeeze mold casting

Superplastic gas pressure formability of the Zr65Al10Ni10Cu15 bulk metallic glass (BMG) sheets was examined. Fabrication of large surface BMG sheets with fully amorphous structure and development of a special gas-blow-forming setup where oxidation and crystallization could be avoided during sample heating and forming were essential for this purpose. The sheets were produced by squeeze mold casting. The optimum pressure–time curve for formation of a hemisphere with a diameter of 22 mm was determined based on the analysis by finite element method and the experimental data obtained from tensile tests at 696 K for different strain rates. Gas pressure forming could be completed within 120 s as predicted by the FEM without introducing crystallization in any part of the final product.