Fabrication of ductile Fe-based bulk metallic glasses

Fe-based Bulk Metallic Glasses (Fe-BMGs) represent a new class of advanced materials with a unique amorphous atomic structure that lacks the regular pattern found in most crystalline metals. This structure imparts a combination of high strength, excellent wear and corrosion resistance, and soft magnetic properties, making them ideal for applications where traditional metals may fall short. For example, in the automotive industry, Fe-BMGs are used in components like gears and powertrains due to their superior wear resistance. In electronics, they are employed in transformer cores to boost energy efficiency, while in the biomedical field, they hold promise for applications such as dental implants and surgical instruments due to their biocompatibility. However, the poor glass-forming ability (GFA) of Fe-BMGs produced via conventional copper mold casting limits their size to the millimeter range, which is far from a practically applicable si ze. Moreover, their brittleness at room temperature significantly restricts their broader application across various industries. Additive Manufacturing (AM), commonly known as 3D printing, offers a promising solution by enabling layer-by-layer construction with rapid cooling rates (10108 K/s), which supports the fabrication of fully amorphous Fe-BMGs of larger sizes and complex shapes. However, AM also presents challenges, such as: 1. Partial crystallization in heat-affected zones (HAZs) due to thermal gradients; 2. Solidification defects, such as pores and cracks, are caused by thermal stress during rapid cooling. This project aims to deepen our understanding of the phase formation and crystallization processes in Fe-BMGs under rapid cooling and heating conditions typical of AM. Innovative techniques, such as flash-DSC (Differential Scanning Calorimetry), will be employed to measure critical cooling and heating rates, enabling better control over crystallization. By optimizing microstructures and balancing the amorphous phase with controlled crystallinity, the project seeks to improve the mechanical properties of Fe-BMGs. Additionally, the research will focus on refining the AM process to minimize defects, such as cracks and pores, which often occur due to rapid cooling. Through careful alloy design and processing adjustments, the project aims to develop new Fe-BMGs with enhanced ductility and toughness, paving the way for their use in demanding applications such as structural materials.