In order to reduce stress shielding following a segmental bone replacement surgery requires stiffness matching strategies between the host bone and the implant are required. Carefully engineered implant geometry that can mimic the mechanical performance of the host bone is required to achieve this. The development of Additive Layer Manufacturing (ALM) techniques such as Direct Metal Laser Sintering (DMLS) allows for the fabrication of complex geometries that can achieve targeted mechanical performance. Consequently, this work introduces a sheathed Ti6Al4V additively manufactured tibial implant that mimics the circumferential anatomy of the host bone. Performance evaluation of the implant was carried using experimental and numerical technique under axial compression. Furthermore, the influence of sheathing strategy and sheath thickness on the compressive performance of the implant is parametrically analysed. The results of this study shows a promising sheathed implant that can replace a defective tibia bone segment. The implant is superior to conventional porous implants as it allows for easy implantation in surgical operation and allows for the reduction of stress shielding.

In this study, silver (Ag) and silver–diamond (Ag-D) composites with varying diamond (D) content are fabricated using laser powder bed fusion (L-PBF) additive manufacturing (AM). The L-PBF process parameters and inert gas flow rate are optimised to control the build environment and the laser energy density at the powder bed to enable the manufacture of Ag-D composites with 0.1%, 0.2% and 0.3% D content. The Ag and D powder morphology are characterised using scanning electron microscopy (SEM). Ag, Ag-D0.1%, Ag-D0.2% and Ag-D0.3% tensile samples are manufactured to assess the resultant density and tensile strength. In-process EOSTATE melt pool monitoring technology is utilised as a comparative tool to assess the density variations. This technique uses in-process melt pool detection to identify variations in the melt pool characteristics and potential defects and/or density deviations. The resultant morphology and associated defect distribution for each of the samples are characterised and reported using X-ray computed tomography (xCT) and 3D visualisation techniques. Young’s modulus, the failure strain and the ultimate tensile strength of the L-PBF Ag and Ag-D are reported. The melt pool monitoring results revealed in-process variations in the build direction, which was confirmed through xCT 3D visualisations. Additionally, the xCT analysis displayed density variations for all the Ag-D composites manufactured. The tensile results revealed that increasing the diamond content reduced Young’s modulus and the ultimate tensile strength.

Manufacturing is an important pillar of socio-economic development, but it has a large carbon footprint and causes serious damage to the ecosystem. There is significant pressure on the manufacturing sector to embrace eco-friendly manufacturing technologies to reduce its environmental burden. Metal Additive Manufacturing (MAM) is a rapidly evolving field with promising prospects to balance the economic and ecological concerns. Recently, manufacturing businesses started to examine MAM as a potential route to strengthen their eco-footprint and improve sustainability performance. The shift from Conventional Manufacturing (CM) processes to MAM requires significant capital investment, staff training, and possibly changing the business model. This may lead to hesitancy among enterprises to take on such risks without guaranteeing the sustainability benefits of MAM. This paper conducts a comprehensive review and critical evaluation of the environmental and economic impacts of MAM. The paper draws guidelines on the best production contexts that enable the fulfilment of environmental goals and maintain economic viability through MAM technologies. In general, Powder Bed Fusion (PBF) techniques are considered environmentally friendly and cost-effective for small-scale production of lightweight small parts with complex shapes and relatively high resolution. In contrast, Direct Energy Deposition (DED) processes are valuable for repairing and manufacturing large-scale parts that have medium shape complexity and relatively low resolution.