Q&A: Professor Geoff Scamans

Materials World magazine
,
11 Jun 2014

From the rural British town of Banbury to the USA and back again – Professor Geoff Scamans’ 40 years as a metallurgist in automotive and aerospace is anything but dull. Now Chief Scientific Officer at Innoval Technology Ltd, UK, he gives Melanie Rutherford a snapshot of his eventful career.

How did your education lead you to the transport industry?

My first degree and PhD were both in metallurgy from Imperial College London. I used the high-voltage electron microscope to study stress corrosion cracking of stainless steel, then spent a postdoctoral year examining stress corrosion cracks in high-strength aluminium alloys, to show that such cracking was caused by hydrogen embrittlement of grain boundaries. This led directly to employment as a research scientist at Alcan International Ltd, in Banbury, UK.

What attracted you to the aerospace and automotive sectors?
When I joined Alcan in 1974, the major research interest was in aerospace alloys and in weldable, strong alloys for defence applications. Stress corrosion cracking was a major issue. I was able to build up a research group and publish widely, and to set up interactions with similar groups around the world. My interest in automotive use of aluminium started in 1982, when vehicle manufacturer British Leyland asked Alcan to co-operate on development of technology for mass production of aluminium intensive vehicles. The challenge was to turn aluminium sheet into the lightweight equivalent of steel sheet for car production, and to make it cost competitive. This challenge remains today.

How have you seen the aerospace and automotive industries change over the years?
Aluminium in aerospace has had a difficult few years, responding to the major challenge presented by the use of carbon fibre-reinforced polymer composites. However, this has prompted the industry to develop stronger alloys and to promote the environmental credentials of aluminium compared to polymer-based composite materials, leading to a much more positive outlook for aluminium in airframes. This could provide a major boost to the UK economy, for example with appropriate investment in a metallic wing programme.
Widespread use of aluminium in automotive structures has been a long time coming, as the mass-build technology has been available since the mid-1980s. The turning point was the Jaguar XJ built in 2003, using Alcan sheet-intensive vehicle technology that has now been extended to the latest Range Rover and Range Rover Sport vehicles, and most recently to the Ford F-150 truck.

Major changes are now being driven by environmental legislation and end-of-life vehicle recycling requirements, the main factors promoting the more widespread use of aluminium in transport applications.

What are the biggest materials challenges currently facing the aerospace and automotive sectors?
For aerospace the challenges are quite simple – stronger and more durable alloys, nearnet shape manufacture, and the provision of smooth low-drag structures without the disruption of rivets. For automotive applications, the challenges are mainly related to end-of-life scrap recovery and high-level recycling of wrought products.

What is your main area of interest?
My main interest still lies in aluminium in cars, but entirely from the perspective of scrap recovery and end-of-life recycling. This is best captured by the cans-to-cars concept, which I have been promoting for the past 10 years. In simple terms, this means that the same end-of-life recycling of aluminium cans back to cans must be the same for an aluminium car. Aluminium is only a green metal in recycled rather than primary form. As part of this, I’m working at Brunel University with Professor Zhongyun Fan, who has developed melt conditioning techniques for impurity tolerance and control. He now has a group of more than 60 people working in this and related fields, for aluminium and magnesium research.

What is the most memorable project you have worked on?
Working for 10 years on the development of aluminium alloys for batteries and fuel cells, which involved constant travelling and multiple visits to North America for Alcan’s then subsidiary, Alupower. Here we explored the most extreme military applications, from drone aircraft to unmanned, undersea vehicles. We understood how to make the aluminium alloys for use as a fuel, but we also learnt that the energy cycle was all wrong for vehicles other than torpedoes and rockets.

What are you currently working on?
Through Innoval, I have been involved in a large number of innovation projects supported by the TSB. The current ones involve replication of anti-reflective motheye structures from anodised aluminium surfaces, high-temperature forming of laserwelded aluminium sheet, cast aluminium alloys that can be riveted without cracking, a novel grain refiner for aluminium casting alloys, and making aluminium automotive sheet alloys from recycled co-mingled domestic waste. And I’m still working on stress corrosion cracking with Henry Holroyd Professor George Thompson at the University of Manchester, using the latest generation of microscopy techniques.

What would you say to encourage aspiring metallurgists into industry?
Aspiring metallurgists are already an endangered species for a whole raft of reasons. Young metallurgists are in increasing demand as the UK economy recovers its manufacturing sector and requires a new generation to provide ‘metals in the service of man’ – particularly recycled metals.

What are the most rewarding aspects of your job?
Working with interesting and demanding people – but most especially in mentoring and career development for students and young researchers at all levels. Even after 40 years of research, every day is different, with fresh challenges and constant interaction with friends and colleagues, not just at Innoval and Brunel, but around the world.  

My life in metals: Career highlights
I was very fortunate to start my doctoral research just as the new 1-MeV EM7 highvoltage electron microscope (HVEM) was being commissioned at Imperial College London, which allowed observation of thicker samples than existing electron microscopes. This was one of six such microscopes funded by the UK Government to stimulate applied microscopy studies and materials research. Under the leadership of my supervisor, Professor Peter Swann, a number of in-situ stages were designed and built. I was able to examine stress corrosion crack tips in austenitic stainless steel in relatively thick electron transparent samples for the first time, to show how cracking developed by a crystallographic dissolution mechanism. This involved detailed analysis and 3D reconstruction of the crack tip using stereographic imaging techniques.

The parallel work on aluminium aerospace alloys was much more controversial and, therefore, more interesting. There was very little support for the hydrogen embrittlement mechanism of stress corrosion crack progression, which was quite obvious from the HVEM images of crack tips that another research student at Imperial had obtained. During my postdoctoral year, and then later at the Alcan Research Centre, I developed a strong case for the hydrogen embrittlement mechanism. This was based on seeing full recovery accompanied by hydrogen evolution, obtaining high-resolution images of hydrogen bubbles on grain boundaries, and generating matching images of striated fracture surfaces. This work would not have been possible without the JEOL 120C Temscan – a state-of-the-art transmission electron microscope (TEM) which, when Alcan bought it in 1974, was both a world-leading scanning electron microscope (SEM) and the first of its kind in an industrial research centre.

Around that time, we had also started some in-situ studies of aluminium oxidation in the HVEM. We were able to directly see oxidation using a hot stage in the microscope vacuum, which allowed us to quickly understand how oxidation of AA5xxx aluminium–magnesium alloys as well as AA8xxx aluminium–lithium alloys could be controlled by trace additions and atmosphere modification. I became a competent microscopist and worked by the mantra that images have to be both meaningful and aesthetically pleasing to be worthy of publication or in any way being called a result. It was also instilled in me to leave everything to the last minute when presenting the latest result – a habit I still work by today.

In the early 1980s, Alcan’s research system was transformed and I was encouraged to rebrand our work on corrosion and oxidation to be more positive. This inaugurated the concept of surface engineering: the control and exploitation of the oxidation of aluminium surfaces. Stemming from this, the Banbury surfaces group generated some exceptional ideas that have been widely exploited and remain active global research interests.
Around that time, I was asked to lead the anode development work for the use of aluminium as a battery fuel, working with John Hunter, in Banbury, and Professor John Sykes at the University of Oxford. Using a simple in-situ cell that could be run as a battery and then placed directly in a scanning electron microscope (SEM) once activated, we saw that there were only 10 elements that could activate aluminium and that the most dominant activator controlled the anodic properties. These simple observations completed Alcan’s anode alloy development project.

In 1982, Alcan set up a small company called Alupower in New Jersey, USA, to market the aluminium anode-based power source technology to the US military. Working for the subsidiary was a massive learning experience that, in particular, honed my proposal writing skills. Following the sale of Alupower in 1995 as Alcan concentrated on its core business, I returned to Banbury to find a laboratory totally focused on supporting aluminium rolled sheet products. This time, I was asked to develop a better understanding of the aluminium rolled sheet surface, and how it should be effectively cleaned and pre-treated without using environmentally unfriendly chemicals such as chromates and fluorides.

Fortunately, I was able to develop, set up and coordinate an EU Brite Euram project in this field and also to fund Xiarong Zhou on a postdoctoral contract at the University of Manchester from 1996 to 2002. Following on from work at the Norwegian University of Science and Technology, in Trondheim, which showed ultrafine grain structures on the surface of rolled aluminium sheet, Xiarong used ultramicrotomy and TEM to look at every aluminium rolled surface we could find. The study showed that all rolled aluminium surfaces have a deformed surface layer that is formed under high shear deformation. This was a major breakthrough, as this surface layer controls many aspects of the behaviour of rolled materials – from corrosion resistance under paint to the durability of adhesive bonds and the appearance of canstock. This has made solving aluminium surface treatment issues much more straightforward, as the critical step is to minimise the development of a deformed layer and to ensure that the layers are removed during the cleaning stage. After good cleaning treatment, almost all pre-treatments can be made to work if they provide good adhesion, without the need for dangerous or damaging chemical systems. Deformed surface layers are now understood to be a feature of all worked metals, almost irrespective of the working process, and show that the pioneering work of Sir Frank Beilby, who first reported such layers, was of enormous significance.

Working on the Brite Euram project in Banbury, Andreas Afseth, then a student from Trondheim, used glow discharge optical emission spectroscopy in combination with high-resolution low-voltage SEM, painstakingly transferring samples between the two instruments to develop a 3D understanding of microstructure, surface chemistry and corrosion performance. This was one of the early studies that eventually led to the revolutionary 3D microscopy, based on ultra-microtomy in SEM, that is world leading in its application to metallic materials by the materials group at the University of Manchester.

Following the closure of the Alcan research centre in Banbury in 2003, I became Chief Scientific Officer of Innoval Technology. It was here that I met Professor Fan at an early TSB call briefing session, back when the organisation was part of the UK Department of Trade and Industry (DTI). Since then, he and I have worked together on a variety of projects, during which time I was appointed as a Professor of Metallurgy at Brunel University, in 2006.
Although we have been successful in developing strong EPSRC and TSB funding streams based on Professor Fan’s technological innovations in liquid metal treatment, one of my main achievements was insisting that recycling was written in as a critical feature of every proposal, and that the only way to understand nucleation was to examine it on oxide particles and grainrefining compounds at the highest available resolution, which we did in collaboration with the University of Manchester. This work unlocked the key features of nucleation during solidification, and promises major future technological innovation and development in both light metals and across the metal material spectrum. It is also the cornerstone of a major investment in metallic materials research at Brunel.

My career highlights are all moments of insight when simple solutions to complex problems have become suddenly clear, almost invariably based on high-resolution metallographic observation. These are particularly rewarding when they can be applied in industrial production processes, used to predict metallic behaviour or to solve long-standing, intractable problems with cost-effective solutions.

For more information, email Geoff Scamans geoff.scamans@innovaltec.com