Aruntapan Dash

The scalable fabrication of structural‐grade aluminum metal matrix composites (A‐MMCs) remains constrained by inherent limitations of conventional processing routes and laser‐based additive manufacturing (AM) methods. In this work, we demonstrate the development of a hybrid wire arc directed energy deposition (WA‐DED) platform for the near‐net‐shape manufacturing of Al4043–B ₄ C composites, uniting high‐throughput wire deposition with spatially controlled in situ powder delivery. A comprehensive suite of microstructural and mechanical characterizations reveals 79% improvement in microhardness and 27%–53% improvement in yield strength. At the same time, the in situ addition of ceramic particles also contributed to enhanced porosity (∼10%) compared to the AMed monolithic Al4043 counterparts with no significant variation in grain size, reflecting the current limitations of first‐generation powder delivery control. Hence, the study establishes a robust proof‐of‐concept for hybrid wire–powder DED as a viable pathway for large‐scale A‐MMC fabrication, while identifying key process refinements necessary for achieving targeted reinforcement efficiency and microstructural uniformity.

Stainless steel 316L (SS316L) is widely used in fracture management devices. However, SS316L does not offer any bacterial infection resistance and can cause metal-ion sensitivity due to Ni-ions’ presence. 17-4PH can emerge as a promising substitute due to the intrinsic antibacterial properties of copper, a 75% reduction in nickel content, and superior mechanical properties. SS316L and 17-4 PH were manufactured using laser-directed energy deposition (LDED). 17-4PH specimens surpassed the compressive strength of SS316L by over 150%. A static magnetic field was generated in 17-4 PH specimens to understand in vitro bone cell-material interactions. In vitro human fetal osteoblast cell culture and bacterial inhibition study using Staphylococcus aureus and Pseudomonas aeruginosa were carried out on these specimens with SS316L as control and as-processed and magnetized 17-4 PH as treatments. Results demonstrated that magnetized 17-4 PH exhibited 25% enhancement in hFOB proliferation and 70% reduction in bacterial colonization compared to SS316L.

Additive manufacturing (AM) of metals attracts attention because it can produce complex structures in a single step without part-specific tooling. Wire arc additive manufacturing (WAAM), a welding-based method that deposits metal layer by layer, is gaining popularity due to its low cost of operation, feasibility for large-scale part fabrication, and ease of operation. This article presents the fabrication of cylindricalshaped mild steel (ER70S-6) samples with a gas metal arc (MIG)—based hybrid WAAM system. A mechanism for actively cooling the substrate is implemented. Deposition parameters are held constant to evaluate the impact of active cooling on deposition quality, inter-pass cooling time, and internal defects. Surface and volume defects can be seen on the cylindrical sample fabricated without an active cooling setup. Defect quantification and phase analysis are performed. The primary phase formed was α-iron in all samples. Actively cooled deposition cross section showed a 99% decrease of incomplete fusion or porosity, with temperature measured 60 s after deposition averaging 235°C less than non-cooled. Microstructural analysis revealed uniformity along the build direction for actively cooled deposition but non-uniform microstructures without cooling. Hardness decreased by approximately 22HV from the first layer to the final layer in all cases. Property variation can be attributed to the respective processing strategies. The current study has demonstrated that active cooling can reduce production time and porosity while maintaining uniform microstructure along the build direction. Such an approach is expected to enhance the reliability of WAAM-processed parts in the coming days.