How pore morphology impacts stiffness

Our most recent study on how pore size, morphology and orientation have an effect on stiffness of a porous alloy has been published in the Journal of Materials Engineering and Performance.

Our article ‘Effect of Pore Size, Morphology and Orientation on the Bulk Stiffness of a Porous Ti35Nb4Sn Alloy‘ describes how the metal foams of a titanium alloy were designed to study porosity as well as pore size and shape independently. These were manufactured using a powder metallurgy/space-holder technique that allowed a fine control of the pore size and morphology; and then characterized and tested against well-established models to predict a relationship between porosity, pore size and shape, and bulk stiffness. Among the typically used correlations, existing power-law models were found to be the best fit for the prediction of macropore morphology against compressive elastic moduli, outperforming other models such as exponential, polynomial or binomial.

The new coefficients reported in this study contribute toward a design tool that allows the tailoring of mechanical properties through porosity macrostructure. The results show that, for the same porosity range, pore shape and orientation have a significant effect on mechanical performance and that they can be predicted. Conversely, pore size has only a mild impact on bulk stiffness.

The full article can be found here

The DOI is https://doi.org/10.1007/s11665-018-3380-0

 

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Materials Research Exchange 2018

We spoke at the UK Advanced Material Research & Investor Showcase event in London on 13th March. The event, organised by EPSRC, Innovate UK and KTN, and supported by DSTL, was aimed at materials scientists and engineers who work at the research:industry:academia interface in the UK. It was a fabulous opportunity to learn more about the facilities the UK plcs and Universities have for materials processing and characterization, and also to find out more about the ongoing projects co-sponsored by Innovate UK.

We were invited to present our ongoing project in collaboration with FAR UK Ltd, ‘L3:An Integrated approach towards zero net emissions via lightweight manufacturing’, which is researching how to achieve weight reduction in composites (i.e. fibre-reinforced polymers) without sacrificing mechanical performance, and using a cost effective manufacturing process.

The process under development is one that has the ability to use lower cost composite materials and is inherently near-zero waste, both in its production strategy and also because it does not use environmentally damaging materials.

The process makes porous polymeric structures where the inherent loss of mechanical properties is mitigated by the addition of fibres (initially glass and carbon, expected to be replaced by naturally derived fibres in the near future).  Additionally, the microstructure of the pores and the orientation of the fibres can be controlled in-situ using external means such as sonication and magnetic fields.

This project is allowing us to move forward towards the realisation of topology optimisation and its true implementation for composite manufacturing processes.

A manufacturing protocol for the production of biocompatible porous catalysts

Mohammad Alqahtani, researcher of the Multifunctional Materials Lab, is conducting research to develop a new manufacturing method and testing protocol for the fabrication of biocompatible catalyst-carrier for controlled drug delivery. The carrier could be used as a prodrug activation agent when implanted in cancerous tissues in the human body. When orally-ingested drugs are deployed into the area under treatment through the blood stream, the catalyst could activate the prodrugs and these affect the area by releasing anticancer treatment. In this research, a titanium-based carrier was used to manufacture the medical device due to their biocompatibility and non cytotoxicity.

In a feasibility study, the samples were made as porous carriers.  Porous materials have larger surface area than solid materials. Therefore, when the contact area between the drug and the carrier increases this has a potency effect on the effectiveness of the drug.

His work has been presented recently

This work is a continuation of the research work already presented here and published here and here.