Overcoming geometric limitations in metallic glasses through stretch blow molding

• Published in: Applied materials today 2020-06, Vol.19, p.100567, Article 100567
• Main Authors: Ojeda Mota, Rodrigo Miguel, Liu, Naijia, Kube, Sebastian Alexander, Chay, John, McClintock, Hayley D., Schroers, Jan
• Format: Article
• Language: English
• Subjects: Bulk metallic glass; MATERIALS SCIENCE; Stretch blow molding; Superplastic forming; Thermoplastic forming
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2020.100567

[Display omitted] •Stretch blow molding provides a new processing method to fabricate high aspect ratio BMG complex shapes.•Shapes requiring strains of over 2000% can be achieved.•Thickness distribution can be quantified and estimated through a mathematical model.•Amorphous state with associated high mechanical properties can be maintained throughout the stretch blow molding process. Bulk metallic glasses (BMGs) exhibit remarkable mechanical properties, such as high strength and elasticity, which is often paired with fracture toughness. Their supercooled liquid region gives rise to plastic-like processing and suggests parts and shapes that can otherwise not be obtained for crystalline metals. However, current processing techniques only allow for limited options in terms of geometry, thicknesses uniformity, and shape complexity. Here we introduce a new processing technique, “stretch blow molding,” to expand the range of possible parts and increase the available geometries that can be fabricated with BMGs. Additionally, a model is derived that allows for the quantification and prediction of stretch blow molding and provides insight into its potential use and limitations. We demonstrate that with stretch blow molding overall strains exceeding 2000% are achievable, compared to the previously reported ∼150% of blow molding. With the ability to stretch blow mold shapes that were previously unachievable with any other metal fabrication technique in a fast and economical manner, and the superb properties of BMGs, we look forward to a broad commercial adaptation of this technique.