A 400 W high-power laser was used to fabricate 200-µm-thick Ti-6Al-4V samples to evaluate the effects of small (50 μm) and large (200 μm) beam diameter on density, microstructure and mechanical properties. A series of single-track experiments demonstrated that it was challenging for the small-beam laser to fabricate smooth and defect-free scan tracks. A larger beam diameter efficiently avoided process instability and provided a more stable and uniform melt pool. By increasing the beam diameter, the density of multilayer samples reached 99.95% of the theoretical value, which is much higher than that achieved with the small beam diameter. However, it was difficult to completely eliminate defects due to serious spatter and evaporation. Moreover, all of the generated samples had relatively coarse surfaces. For the large beam diameter of 200 µm, the optimal yield strength, ultimate tensile strength and elongation were 1150 MPa, 1200 MPa and 8.02%, respectively. In comparison, the small beam diameter of 50 µm resulted in values of 1035 MPa, 1100 MPa and 5.91%, respectively. Overall, the large-diameter laser is more suitable for high-power selective laser melting (SLM) technology, especially for thick layers.

In this work, the role of long period stacking ordered (LPSO) phase in the crack propagation behavior of an as-cast Mg_95.5Y₃Zn_1.5 alloy was investigated by dynamic four-point bent tests. The as-cast Mg_95.5Y₃Zn_1.5 alloy is mainly composed of Mg matrix, 18R LPSO phase located at the grain boundaries and 14H LPSO phase located within the Mg matrix. The alloy exhibits excellent dynamic mechanical properties; the yield stress, maximum stress and strain to failure are 190.51 ± 3.52 MPa, 378.32 ± 4.26 MPa and 0.168 ± 0.006, respectively, at the strain rate of ~3000 s⁻¹. The LPSO phase effectively hinders dynamic crack propagation in four typical ways, including crack tip blunting, crack opening inhibition, crack deflection and crack bridging, which are beneficial to the mechanical properties of the alloy under dynamic loadings.

Wire Arc Additive Manufacturing holds promise for on-board metal part production in maritime settings, yet its implementation remains limited due to the vibrational instability inherent to shipborne environments. This study addresses this critical technological barrier by analyzing the effects of marine vibrations on process stability and proposing an integrated solution based on adaptive process control, gyrostabilized platforms, and real-time monitoring systems. The research establishes specific technical requirements for WAAM instrumentation under maritime conditions and evaluates the capabilities and limitations of existing hardware and software tools. A set of engineering recommendations is presented for improving digital modeling, thermal–mechanical monitoring, and feedback control systems. Additionally, the study highlights material-related challenges by examining the influence of alloy properties on print quality under dynamic loads. The proposed approach enhances WAAM process resilience, laying the groundwork for reliable, high-quality additive manufacturing at sea. These findings are particularly relevant to shipboard maintenance, repair, and remote fabrication tasks, marking a significant step toward the industrial adoption of WAAM in marine engineering.

Samples of marine surimi made from six different fish types have been comprehensively investigated and compared in terms of chemical composition, protease activity, gelling chemistry, gel properties and 3D printability. It has been found that surimi with high protein content, low fat concentration, low activity of endogenous protease (cathepsin B, cathepsin L, cathepsin D, calpain and serine protease) and low TVB-N showed better gelling capacity and gel properties. However, the 3D printability of surimi was more relevant to apparent viscosity. The surimi with viscosity between 5000 Pa·s and 12,000 Pa·s yielded better printing performance as indicated by higher printing accuracy than 97% and less cooking loss. This study clarified the effects of marine fish types on the corresponding surimi gelation and gel properties, and successfully established relationships between surimi properties and 3D printing performance, thus providing new insights on exploring new surimi sources and developing 3D surimi printing techniques.

The application of Wire Arc Additive Manufacturing for metal component fabrication on marine vessels and offshore platforms remains a significant challenge and an under-explored research domain. The primary obstacle lies in the dynamic and complex nature of the maritime environment, which imposes severe constraints on the operational stability of 3D printing systems. Methodologically, the article presents an analysis of the problems of using WAAM technology in the marine environment, as well as a theoretical analysis of the functionality, advantages and limitations of technical and software tools designed to improve the reliability of WAAM technology in marine conditions. The findings indicate that while WAAM offers notable adaptability and flexibility, maintaining print quality remains a challenge due to the high sensitivity of the process to fluctuations in thermal and mechanical conditions, particularly under the influence of shipborne vibrations. To accelerate the adoption of WAAM technology in maritime industries, this study synthesizes existing research aimed at improving instrumentation for effective WAAM implementation. Specific technical requirements for deploying WAAM on marine vessels are identified, alongside a critical assessment of current software and hardware solutions that could enhance the robustness of WAAM in offshore environments. Furthermore, recommendations are provided for advancing digital modeling, real-time monitoring, diagnostic methodologies, and process control to optimize WAAM for marine engineering applications. The study also delineates the functional properties of various metals suitable for WAAM-based manufacturing in maritime settings, highlighting their respective benefits and limitations. Ultimately, enhancing instrumentation for high-quality 3D printing is identified as a key driver for ensuring the competitiveness and innovation potential of WAAM technology in the maritime sector.