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This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young's modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young's modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes. [ABSTRACT FROM AUTHOR]

Tramp elements in steels such as tin have been thought harmful because of the hot brittleness at grain boundaries and will be enriched in new steels because of difficulty of removal. It has been an important and difficult matter for metallurgist to use these elements. In the present paper, the as-cast steel containing high concentration of tin is prepared in laboratory and tin precipitates at the manganese sulphide inclusions have been found. A theoretical model is established to calculate the size of manganese sulphide inclusions acted as the heterogeneous nucleation site of tin precipitation. The results show that the inclusions with the smaller contact angle between tin precipitate is more advantageous to be the nucleus of tin heterogeneous nucleation. In this experiment, the manganese sulphide inclusions whose size is 2~4 μm in diameter can act as the nuclei of the nucleation of tin precipitation.

Highlights Due to the exceptional flame retardancy, environmental protection, cost‐effectiveness, and ease of processing, halogen‐free flame‐retardant polyethylene (PE) composites are attracting wide attention. However, the addition of halogen‐free flame retardants usually leads to significantly decreased mechanical properties of PE composites, which greatly limits its application. Herein, we report a halogen‐free flame‐retardant PE/ethylene‐vinyl acetate copolymer composite (PE/EVA) with excellent flame retardancy and mechanical properties by combining compatibilizer, crosslinking agent, and carbon fiber. The presence of compatibilizer not only improves the compatibility of halogen‐free flame retardants and matrix, but also interacts with the crosslinking agent to form a cladding structure on the surface of carbon fiber. The enhanced interaction between carbon fiber surface and matrix then results in significantly enhanced flame retardancy and mechanical properties of the composite. Specifically, adding 4 phr compatibilizer, 0.5 phr crosslinking agent, and 10 phr carbon fiber will lead to the halogen‐free flame‐retardant PE/EVA composite with a UL‐94 V‐1 level, limiting oxygen index of 27.1, and an increased tensile strength by 84.02% reaching 19.12 MPa. Moreover, further carbon fiber surface modification can further enhance the flame retardancy of the composite probably due to a synergistic flame‐retardant effect caused by the surface modified nitrogen and silicon elements. As a result, the composite achieves UL‐94 V‐0 level and the limiting oxygen index of 27.7 with well‐retained high tensile strength of 15.19 MPa. This work provides a practical strategy for enhancing the flame retardancy and mechanical property of PE‐based composite simultaneously. Compatibilizer interacts with crosslinking agent to form a cladding structure on the surface of carbon fiber. Crosslinking agent promotes the formation of chemical bonds between modified carbon fiber, compatibilizer, and matrix. Carbon fiber surface modification can enhance the flame retardancy of the composite due to the synergistic flame‐retardant effect. [ABSTRACT FROM AUTHOR]