Mr. Schauerte, what materials will you be using to build the VW Golf in 2025?
Mostly steel, just like today’s models. I personally believe that steel still has a long future ahead of it. It’s hard to think of any group of materials that can boast such incredibly dynamic developments as steel. It’s a very exciting field. In the past, the only way to strengthen steel was to increase the carbon content and
sacrifice some of its plastic malleability or ductility. But nowadays we have steel alloys containing manganese, boron and silicon, the so-called TRIP and TWIP steels, as well as various other developments. So we no longer have to make that compromise. These new steels offer both high strength and great ductility, and that makes them particularly useful for building car bodies.
What about the trend towards a greater mix of materials that everyone’s talking about?
Well, that’s certainly happening — but you asked me specifically about the VW Golf! New materials are generally introduced in models in the upmarket segments and then make their way down to midsize and smaller vehicles. Steel will continue to dominate these price segments for a long time to come, though we will also see increasing use of aluminum and magnesium.
But if you look at the Bugatti “Veyron”, for example, you’ll see that it already contains stainless steels, high-alloy aluminum, titanium, carbon-fiber-reinforced plastics and magnesium. The more you move down through the price range, the more steel you’ll find. But whatever class of vehicle you look at, new models will always have a more diverse range of materials than their predecessors, and that applies to the Golf, too. So don’t worry, the trend towards a multi-material mix is still going strong!
A multi-material mix! Bring it on! But steel still has a great future ahead of it, too.
Why do new materials always start at the top and work their way down?
It’s partly to do with the cost of light-weight materials themselves, and partly a question of the manufacturing methods that we tailor so carefully to each particular material. The effort and cost involved in introducing new materials is directly dependent on the number of units you’re producing.
The smaller that quantity and the lower the number of production sites, the more radical we can be in terms of lightweight construction. We have a unique situation in the Volkswagen Group because we offer such a broad array of vehicles ranging from the Bugatti Veyron and Audi A6 to our high-volume Seat and Volkswagen cars. We transfer our material know-how from one brand to another.
In which assemblies will these materials be found in the future?
There will be more aluminum, but not necessarily where you’d expect it. So not just in the car body, but also in areas like fittings and the transmission. There’s also potential for using this material in the engine, auxiliary units and piping.
Alternative materials are the common theme running through Oliver Schauerte’s life. He wrote his dissertation on high-temperature fatigue in a titanium alloy. In 1998 Schauerte joined the VW research department and was quickly appointed project manager for titanium and special materials. Schauerte headed up development work for lightweight engineering at Bugatti and was in charge of technology and the development of properties in fibercomposite plastics at Audi. On May 1, 2015 he was appointed head of materials research and manufacturing processes at the Volkswagen Group.
And what does the future look like for fiber-reinforced plastics?
CFRP and similar materials perform so well that they can be used almost anywhere. I expect to see more glass fiber and carbon-fiber-reinforced composites in exterior components for sports cars. When it comes to components with large surface areas, fiber-reinforced plastics are the light-weight solution. Take a supercar such as the Lamborghini “Aventador”, for example, and you’ll see that the structural shell is made entirely of CFRP. For the majority of vehicles, however, CFRP will continue to be too pricey even over the long term, in part because CFRPs are either too difficult or even impossible to repair.
CFRPs certainly spearheaded the lightweight construction boom, but they’re not always the best solution when it comes to meeting other requirements. CFRP manufacturers have ex-panded the range of materials carmakers use, and that has actually had the effect of encouraging innovation among traditional steel and aluminum manufacturers. That has really fired up the materials market!
We want to design materials to our specifications.
How will you join all of these materials together?
The joining techniques can basically be divided into three categories: mechanical, chemical (e.g. gluing), and thermal (e.g. welding). We’re carrying out comprehensive research into all these areas; we’re not committed to just one of them. But I can say that friction stir welding is definitely something we will be using for steels of significantly different strengths. The combination of riveting and gluing also offers a whole number of advantages.
One challenge, for example, is making sure to avoid heat distortion when you’re joining something like CFRP to steel or aluminum. We’ve encountered a curious problem while riveting high-strength steels. As steels get stronger, we have to increase the setting speed for the rivets, and we actually ran into trouble with the firearms regulations! They insist on stringent safeguards for projectiles fired at more than 30 meters per second, so our research associates would have to have a firearms license. That’s not necessarily what you want on the factory floor.
What about laser processing?
Laser welding is a pioneering technique in our industry. I think we can expect to see greater efficiency in the manufacturing process, especially with the new opportunities offered by remote welding. And when it comes to gluing or the combination of riveting and gluing, we need lasers to pretreat the surfaces. And, of course, if the volume of CFRPs continues to increase, then lasers could be of interest to us as a good cutting tool.
What changes do you anticipate in the lightweight materials we use today?
As regards further developments for aluminum, we seem to be reaching our limits and any progress now is happening in small increments. Research efforts should really focus on the processing methods — for example investigating how we can manufacture components cost-efficiently and join them in composite structures without impairing their properties as materials. In the case of fiber-reinforced plastics, I’m hoping that manufacturers will be able to drive down the cost per part even further.
When I think about the future, I dream about changing the physical properties of structural materials.
What’s the focus of your research at the moment?
Well, we’re taking a close look at the physics of the matter for a start. We’re working on quantum mechanical simulations that model interactions between different metals on an atomic level. We want to discover the best ways to form alloys and metallic materials.
You mean you’re actually looking at individual atoms?
Absolutely. What we have at the moment is an experience-based development process for materials. Put simply, that means you have an aluminum alloy and you add a little bit of element X and a little bit of element Y and watch what happens to the alloy. That’s not precise enough for us.
In the future we want to simulate in advance how the material’s behavior will change if we mix in certain elements. But to do that we need to know how the atoms interact. Ultimately we really want to be designing materials to our specifications.
What materials can we expect to see in the future? What’s the next big thing?
I’m confident that hybrid and sandwich materials will be a major trend in the future. Take metals, for example. When it comes to structural materials we only really have four basic elements to choose from in auto manufacturing: iron (i.e. steel), aluminum, magnesium and titanium. All the other elements are inferior to at least one of these elements. That’s not a very wide choice, and even with alloying you can’t really alter the physical properties of those four metals — such as their stiffness — to any great degree.
Sandwich materials will be the trend of the future.
If I could wish for one thing, then I would like to be able to modify the physical properties of these substances. That’s something you can only achieve by teaming them up with other materials: aluminum with fiber-reinforced composites, steel with plastic, casting alloys with ceramic or silicon particles, and so on. Those are the new groups of materials I think we’ll be seeing in the future.