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profile7euMicroscopyandAnalysis | July/August 2017more significant," he says. "So I have always been interested in structural integrity and the prediction of failure. And I have always focused on where failure really is important, and that includes oil and gas, nuclear and aerospace applications."Working at the European Synchrotron Radiation Facility and later at the newly built, UK-based Diamond Light Source, Withers showed how X-rays could be used to investigate crack and cavity formation in large steel samples. His developments included novel time-lapse experiments to predict failure mechanisms in components, and he also exploited the brilliance of the synchrotron beams to map stress development in welds at very high resolution.In related research, Withers was also using X-ray computed tomography at synchrotrons to study, for example, the growth of corrosion cracks along grain boundaries at micron-resolution. And, importantly, he also pioneered X-ray microscopy, combining diffraction and imaging modes, to glean fracture mechanics detail on the driving forces behind cracks."We were able to use X-rays to not only collect a 3D image, but to create 3D movies where we could, for example, watch the nucleation and growth of defects in components," he says. "This ability to do time-lapse imaging - in-situ - was one of the big things we managed to do at this time."As Withers' X-ray analysis methods progressed at speed, advances in X-ray CT scanners were also coming in thick and fast, meaning an X-ray imaging facility in Manchester was now a real option. This led to the foundation of the Manchester (Henry Moseley) X-ray imaging facility, now regarded as one of the most extensive multi-scale X-ray imaging laboratory in the world.Headed up by Withers, the facility is home to a vast array of instruments, including X-ray CT scanners, tomography systems and microscopes, supported by in-situ equipment. Meanwhile, research is complemented by synchrotron X-ray imaging at ESRF, Diamond Light Source and the Advanced Photon Source. "We can use different methods to study [samples] from a large scale right down to a fine scale," says Withers. "Each length scale provides you with new knowledge as well as strategies to stop a degradation process."And as the researcher highlights, facility users can make some of the fastest and highest resolution X-ray images in the world across a vast range of time-scales. "The X-rays in synchrotrons are very intense, giving us very high-resolution images, very quickly, which is great for capturing fracture in real-time," he says."However, we can use the lower intensity X-rays in our lab to look at, say, longer-term failures," he adds. "We may only take one or two frames a second, but this is good if you are taking time-lapse sequence images of corrosion over many months."But the Manchester X-ray Imaging Facility has not just been about materials failure analysis. According to Withers, his research alone has shed light on the structural performance of bone, structural changes during butterfly pupation and lithium battery degradation, as well as structure-property relationships in artificial skin."We have this wonderful facility here... for example we found ourselves studying parasites in the gut as we could use the same techniques to locate a parasite as we have used to identify a void in a metal matrix composite," he says.Indeed, Withers believes collaboration with other researchers from different areas of Materials Science, and across disciplines, has been paramount to his success. "Some people can spend a lifetime focusing on one topic and they are Tomographic sections from the centre of a C-cored fibre before testing at an intermediate stage and after full fragmentation. A 3D semi-transparent visualisation of a wedge-crack is also shownWithers et al, "Monitoring the Interface in Metal Matrix Composites", ESRF Highlights, 2004spider Computed tomography of Huntsman spiderDunlop et al. "Computed tomography recovers data from historical amber: an example from huntsman spiders", Naturwissenschaften 98, 6: 519-527

profile8euJuly/August 2017 | MicroscopyandAnalysisthe go-to person if you want to know something about a type of material, or process," he says. "But my real fascination has been about making connections; I like to see things in one area and apply this to another, or work with people with different skills to do something new."Beyond X-rays and neutronsWith his research and facilities, thriving, Withers received the biannual Royal Society Armourers and Brasiers' Company Prize in 2010 to recognise his pioneering use of neutron and hard X-ray beams to map stresses and image defects in industry-scale components.But X-rays and neutrons have not been enough. Around this time, Withers also started to look at combining X-ray imaging with electron imaging, in a process he calls 'Correlated Tomography'."X-rays can do certain things – they cover time and different length-scales from the metre to tens of nanometres – but the electron microscope allows us to go even finer," he explains. "Biologists have already developed correlative microscopy by combining optical and electron microscopy, and basically we're extending what they've done to three dimensions."Still, as Withers points out, following a small volume of interest buried deep inside a material, as you move from one instrument to another, isn't easy.But thanks to significant research funding, he and colleagues have devised a correlative set-up combining X-ray computed tomography with serial section FIB-SEM, electron backscatter diffraction and TEM elemental analysis. In one example of their research, they used different techniques to study corrosion at different scales."We are able to study the mechanisms at each scale and develop strategies at atomic levels and coarser scales, to prevent corrosion and extend component life," explains Withers.His lab was also the first to exploit the milling capabilities of a plasma focused ion beam (FIB) and excise regions identified at a coarser scale for finer serial section section tomography (SST) in a electron microscope."This is rather like gaining a 3D image of a loaf of bread by cutting it up into many fine slices," says Withers. "It is paving the way to higher resolution serial section tomography on larger volumes."But advanced tomography aside, for Withers himself, the progress never stops. In 2012, he became the inaugural Director of the £64 million BP International Centre for Advanced Materials, (ICAM) working with Universities of Cambridge, Imperial and Illinois, to better understand and develop materials across the energy industry.Come 2014, his facility was awarded The Queen's Anniversary Prize in recognition of the impact, excellence and innovation in X-ray imaging. And during 2016 he was elected a Fellow of the Royal Society, before becoming the first Regius Professor of Materials in the UK earlier this year.Recently, Withers has stepped down from the BP ICAM to steer the new £235 million Henry Royce Institute for Advanced Materials. As Chief Scientist, he will be leading researchers from the Universities of Sheffield, Leeds, Liverpool, Cambridge, Oxford and Imperial College London, as well as the Culham Centre for Fusion Energy and National Nuclear Laboratory to drive advanced materials research forward for UK industry."I see the Royce as an opportunity to create a real buzz of people coming and going, discovering new things and working together," he says. "We will not be putting our resources in boxes and keeping them for ourselves; instead, we want people to be here, doing new things we hadn't anticipated they would be able to do."Looking to the future, Withers eagerly awaits the wider use of free electron lasers. "These are the next generation of synchrotrons if you like, which will give us an even more intense way of looking at things," he says.And for up and coming researchers, he believes key global challenges should be tackled, and Materials Science lies at the heart of these."We need a safer world, a world where everyone has enough water and enough to eat, and a world where our use of energy doesn't damage the planet," he points out. "My suggestion to young scientists would be to ask, where can Materials Science make an impact?""And importantly, remember inspiration comes from many, many angles; so never be too precious to work with other people," he adds.blade, above left, Wide core fan blade being measured on ENGIN-X, in 2004 and recent research at ENGIN on an aerospace component, above rightwhipworm, below, Trichuris muris, a gut-dwelling whipworm that burrows its head end into the cells lining the intestinesCMYCMMYCYCMYK