Absorbable Metals for Biomedical Applications

Absorbable metals have shown significant clinical potential for temporary implant applications, where the material is eventually replaced by healthy, functioning tissue. However, several challenges remain before these metals can be used in humans. Innovations and further improvements are required. This book collects scientific contributions dealing with the development of absorbable metals with improved and unique corrosion and mechanical properties for applications in highly loaded implants or cardiovascular and urethral stents

Extra low interstitial titanium based fully porous morphological bone scaffolds manufactured using selective laser melting

This is an accepted manuscript of an article published by Elsevier in Journal of the Mechanical Behavior of Biomedical Materials on 29/03/2019, available online: https://doi.org/10.1016/j.jmbbm.2019.03.025 The accepted version of the publication may differ from the final published version.Lattice structure based morphologically matched scaffolds is rapidly growing facilitated by developments in Additive Manufacturing. These porous structures are particularly promising due to their potential in reducing stress shielding and maladapted stress concentration. Accordingly, this study presents Extra Low Interstitial (ELI) Titanium alloy based morphological scaffolds featuring three different porous architecture. All scaffolds were additively manufactured using Selective Laser Melting from Ti6Al4V ELI with porosities of 73.85, 60.53 and 55.26% with the global geometry dictated through X-Ray Computed Tomography. The elastic and plastic performance of both the scaffold prototypes and the bone section being replaced were evaluated through uniaxial compression testing. Comparing the data, the suitability of the Maxwell criterion in evaluating the stiffness behaviour of fully porous morphological scaffolds are carried out. The outcomes show that the best performing scaffolds presented in this study have high strength (169 MPa) and low stiffness (5.09 GPa) suitable to minimise stress shielding. The matching morphology in addition to high porosity allow adequate space for flow circulation and has the potential to reduce maladapted stress concentration. Finally, the Electron Diffraction X-ray analysis revealed a small difference in the composition of aluminium between the particle and the bonding material at the scaffold surface

Dental Implantology and Biomaterial

The discipline of dental implantology is one of the scientific medical/dental fields that are moving dynamically very fast. Not to mention the multiple specialties involved in managing the service as well as the research production. As much as it is necessary to have books to review the basics of bone healing, cellular biology, and implant rehabilitation planning, it is very critical to have more focused books to link the dots and elevate the benchmark of success even higher, especially when facing the reality of more advanced case challenges nowadays. ''Dental Implantology and Biomaterial'' presents four main sections covering topics of clinically applied ''tips and tricks'', the reality of transmucosal implant surface, the future of ceramic implants, the revolution of implant surface treatment, and finally the application of nonautogenous graft in the treatment process. The aim is updating the practitioners, researchers, and postgraduate trainees in the field with up-to-date clinically applied topics focused on reducing the gap between research and clinical application. Doing so will not only optimize the practice but also advance it with evidence-based maneuvers and technical details

3D printing customised stiffness-matched meta-biomaterial with near-zero auxeticity for load-bearing tissue repair

The evolution of meta-biomaterials has opened up exciting new opportunities for mass personalisation of biomedical devices. This research paper details the development of a CoCrMo meta-biomaterial structure that facilitates personalised stiffness-matching while also exhibiting near-zero auxeticity. Using laser powder bed fusion, the porous architecture of the meta-biomaterial was characterised, showing potential for near-zero Poisson's ratio. The study also introduces a novel surrogate model that can predict the porosity ( φ ), yield strength ( σ y ), elastic modulus ( E ), and negative Poisson's ratio ( − υ ) of the meta-biomaterial, which was achieved through prototype testing and numerical modelling. The model was then used to inform a multi-criteria desirability objective, revealing an optimum near-zero − υ of −0.037, with a targeted stiffness of 17.21 GPa. Parametric analysis of the meta-biomaterial showed that it exhibited − υ , φ , σ y and E values ranging from −0.02 to −0.08, 73.63–81.38%, 41–64 MPa, and 9.46–20.6 GPa, respectively. In this study, a surrogate model was developed for the purpose of generating personalised scenarios for the production of bone scaffolds. By utilising this model, it was possible to achieve near-zero − υ and targeted stiffness personalisation. This breakthrough has significant implications for the field of bone tissue engineering and could pave the way for improved patient outcomes. The presented methodology is a powerful tool for the development of biomaterials and biomedical devices that can be 3D printed on demand for load-bearing tissue reconstruction. It has the potential to facilitate the creation of highly tailored and effective treatments for various conditions and injuries, ultimately enhancing patient outcomes

Metal Additive Manufacturing – State of the Art 2020

Additive Manufacturing (AM), more popularly known as 3D printing, is transforming the industry. AM of metal components with virtually no geometric limitations has enabled new product design options and opportunities, increased product performance, shorter cycle time in part production, total cost reduction, shortened lead time, improved material efficiency, more sustainable products and processes, full circularity in the economy, and new revenue streams. This Special Issue of Metals gives an up-to-date account of the state of the art in AM

Additive manufacturing of stiffness optimised auxetic bone scaffold using cobalt-chromium-molybdenum superalloy

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Auxetic materials offer unconventional strain behaviour owing to their negative Poisson’s ratio (−) leading to deformation modes and mechanical characteristics different to traditional porous architecture. This can lead to favourable outcomes for load-bearing tissue engineering constructs, such as bone scaffolds for critical-size defects. Emerging early-stage studies have shown the potential of auxetic architecture in increasing cell proliferation and tissue reintegration due to their −. However, research on the development of stiffness optimised auxetic architecture for biomedical applications including bone scaffolds or implants is yet to be reported. In this regard, the thesis puts forward an open innovation framework for the selective laser melting (SLM) of auxetic bone scaffolds that offer the strength and porosity requirements while offering stiffness matching to a tibia host section. CoCrMo has been chosen as the biomaterial of choice due to its high elastic modulus and density which offered the potential for conceiving highly porous architectures. CoCrMo stiffness matched auxetic bone scaffolds optimised under two scenarios for their potential to offer near-zero and high negative Poisson’s ratio are demonstrated in this thesis. Overall, the investigations carried out in this thesis suggest that CoCrMo auxetic bone scaffolds can be additively manufactured with targeted Poisson’s ratio, mechanical performance and porosity characteristics by algorithmically modifying the design parameters. The surrogate model developed in this thesis can be used for user-defined scenarios to generate scaffolds with near-zero and high −, respectively while offering stiffness matching to host bone. Manufacturers and research institutions can use the validated methodology proposed in this thesis to further refine and generate alternate prototypes to inform further developments in the field of meta-biomaterials

Corrosion Resistance

The book has covered the state-of-the-art technologies, development, and research progress of corrosion studies in a wide range of research and application fields. The authors have contributed their chapters on corrosion characterization and corrosion resistance. The applications of corrosion resistance materials will also bring great values to reader's work at different fields. In addition to traditional corrosion study, the book also contains chapters dealing with energy, fuel cell, daily life materials, corrosion study in green materials, and in semiconductor industry

Thermomechanically processed magnesium-silver alloys as antibacterial and biodegradable implant materials

In this study, “smart” Mg-Ag alloys as antibacterial and biodegradable implant materials were prepared and systematically evaluated. The microstructure of the as cast Mg-Ag alloys with varied silver content was regulated with respect to the grain size and precipitates via different thermomechanical processing. The processing includes casting, homogenization, hot extrusion, equal channel angular pressing (ECAP), friction stir processing (FSP) and rolling with subsequent annealing. The influence of microstructure on tensile properties and degradation behavior was revealed. The cytocompatibility, mineralization, antibacterial properties and degradation mechanism of Mg-Ag alloys were evaluated

Laser Cladding for use in Extreme Tribological Interfaces

Coatings are common in engineering applications for protecting the surface of components, either from exposure to environmental conditions or from contact with other components. Laser cladding is a coating technique which allows for thicker coatings of various alloys that enable high load bearing interfaces to operate at a wider range of loads or for longer, for example by increasing durability. This is of great benefit to the railways industry as well as other heavy industries, such as the steel industry. Laser clad coatings have been used extensively in other industries such as oil and gas for increasing the durability of drilling components; in mining and earth moving equipment, for increasing the durability of the components that come in contact with hard soil and rocks. Both are extreme interfaces. In this study, new interfaces and extreme conditions for new industries are investigated, by highlighting the laser clad coating advantages, when used under extreme conditions. The extreme test conditions have not been investigated in published literature, especially with the use of laser clad coatings. This project evaluated the performance of laser cladding coatings on railway components such as the wheel and rail. Other interfaces found in machinery in the steel industry were considered, specifically in the rolling of steel. A variety of interfaces were evaluated by modelling and testing, such as rolling-sliding, high pressure water jet erosion and impact. Three clad materials were identified as suitable for the chosen interfaces, martensitic stainless steel (MSS), Stellite 6 (Co-Cr) and a two-layer clad of Inconel 625 with Technolase. The clad parameters were fixed, resulting in constant material grades, allowing the coatings used in different interfaces to be comparable. The materials choice was based on published research on similar interfaces. Tests were performed on existing test rigs for rolling-sliding and bending tests. The impact test was performed on a rig modified specifically for this study, while a bespoke rig was built for the erosion test. Metallographic techniques were used for all materials, to prepare the samples for characterisation using optical and electron microscopy, as well as nanoindentation and microhardness. Pre- and post-test material analysis was performed. The use of computer modelling was considered mainly for the generation of test parameters, while the results from testing were compared to existing data. Key findings highlight that the use of the selected clad materials under the chosen extreme interfaces can have a positive effect on the durability of the coating, mainly by increasing the wear resistance properties of the coating. Furthermore, the two-layer clad coating showed promising results in stopping crack propagation to the substrate. The test results can be used in predictive tools by researchers in academia, as well as in industry, as a way of introducing laser cladding applications to interfaces of engineering products. Furthermore, the performance of the chosen materials indicates that this study may be used as the basis for selecting similar clad coatings for pilot trials or large scale testing