Lab diaries: Multifunctional microstructures

We have created new structures that provide comfortable accommodation for bone-forming cells. We seeded them, puffed up their pillows, fed them with their favourite food and drink and waited. The other day we went to check on them. This one looks particularly pleased!

When we fixed the cells we found this shape, decorated with eyes (prob debris from the desiccating chemicals) which we have decorated with a tie

We are functionalising surfaces to tune them to chemical bio markers and embedding intelligence to create active structures and welcoming new homes for cell cultures. Attention to detail: we even decorate their sitting spaces with flowers

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

 

Sonication for the Porosity Gradation of Foams Meets Replica Templating

We have developed a hybrid manufacturing process for the generation of porosity graded structures made out of Ti based alloys (in this case Ti 35Nb 4Sn). Unlike previous processes in which we manufactured these structures using the space-holder technique via a powder metallurgy process, we are now able to incur a high level of control on the micro and microstructure of the metal foam by exploiting the replica templating approach. The template is a sonicated sacrificial structure whose porous structure and distribution is tailored using sonication.

The graphical abstract summarises the approach to this way of manufacturing metal porous materials and foams:

This Paper is Chapter 2 of the Published Proceedings of the 11th International Conference on Porous Metals and Metallic Foams (MetFoam 2019) by The Minerals, Metals & Materials Series (TMS) published by Springer International.