Material Technology’s Pivotal Role in Industry Transformation

For decades, steel and metal alloys have been the preferred materials for vehicle manufacturing, mainly because of their performance and cost. However, current industry trends demand more advanced materials to boost the fuel economy of modern vehicles, while maintaining safety, performance and cost-effectiveness. The industry’s adoption of e-mobility and sustainability trends will be enabled by constant innovation in lightweight materials, magnesium and aluminum alloys, high-performance polymers, 3D-printing, among others.

Lightweight materials offer great potential for increasing vehicle efficiency, as it takes less energy to accelerate a lighter object than a heavier one. A 10-percent reduction in vehicle weight can result in a 6-8 percent fuel economy improvement, according to the US Office of Energy and Renewable Energy (EERE): “Replacing cast iron and traditional steel components with lightweight materials, such as high-strength steel, magnesium alloys, aluminum alloys, carbon fiber and polymer composites, can directly reduce the weight of a vehicle's body and chassis by up to 50 percent and therefore reduce a vehicle's fuel consumption.”

Vehicles are increasingly incorporating new technology components, emission control systems and safety devices. With lightweight structural materials, cars can carry additional components without increasing the overall weight of the vehicle. To replace steel, however, materials must deliver high strength, energy intensity or the ability to absorb impact, manufacturability, minimum weight, corrosion resistance and maintainability, according to the paper “Modern Materials for Automotive Industry,” published by Havorun et al on the Journal of Engineering Sciences.

Moreover, although lightweight materials are important for any vehicle, they are especially important for HEVs, PHEVs and BEVs. Lightweight materials in these vehicles can offset the weight of power systems such as batteries and electric motors, improving efficiency and increasing their all-electric range, according to EERE.

The average vehicle body in the US fleet today is 65 percent steel, 13 percent aluminum, 4 percent magnesium, 6 percent plastic and polymer composites and a variable percentage of glass, adhesives, sealers and foam, as reported by MBN. While automakers continue exploring and developing alternative materials, copper will remain an essential raw material, says Saulo Guzmán, General Manager, Wieland Group: “EVs require a lot of copper. So far, it is used in motors, batteries, inverters, wiring and fuses.” However, EVs require new copper alloys composed of “more specific materials, not the regular copper we used to have in the past.”

Short-Term Lightweight Materials Research

In the short term, R&D is mainly focused on replacing heavy steel components with materials such as high-strength steel, which is stronger and more ductile than typical steel. Advanced high-strength steel can reduce component weight by up to 25 percent, according to EERE. The material can also improve the vehicle’s performance in crashes, while still allowing suppliers to manufacture components using conventional techniques.

Aluminum alloys represent another important alternative for the automotive industry. Aluminum car bodies have already reached mass production, although only for expensive models. Premium brands tend to experiment with aluminum alloys, including Jaguar-Land Rover, Audi and BMW, as reported by MBN.

Thanks to its use in aerospace and construction, scientists have a good understanding of aluminum’s characteristics and processing, says EERE. The main persisting issues with aluminum alloys, however, are cost and manufacturing, in addition to issues with joining, corrosion, repairs and recycling when the metal is combined with other materials. The US’ Vehicle Technologies Office is currently working together with The Pacific Northwest National Laboratory and Ford to improve how manufacturers pre-process sheets of aluminum to increase formability during stamping.

Long-Term Lightweight Materials Research

Advanced materials, such as magnesium and carbon fiber reinforced composites, could reduce the weight of certain vehicle components by 50-75 percent, according to EERE. While magnesium can reduce component weight by over 60 percent, its use is currently limited to less than 1 percent of the average vehicle by weight.

The main barriers for magnesium’s scalability in the short term include the raw material’s high cost and price instability, difficulty to form a sheet with it at low temperatures, low ductility of finished components and difficulties to join, repair and recycle when used in multi-material systems.

Magnesium is currently used in gearboxes, steering columns and driver’s air bag housings, as well as in steering wheels, seat frames and fuel tank covers. The desire to identify solutions and opportunities regarding the use of magnesium in vehicles has been growing over the past years, according to the International Magnesium Association.

Carbon fiber reinforced polymer composites, on the other hand, can also reduce component weight by over 60 percent. However, automakers use carbon fiber only in high-performance vehicles due to the costs of the input material and required processing, which are generally too high for mass-production models, according to EERE.

3D Printing: A Feasible Alternative?

Originally used only for prototyping, additive manufacturing (AM), also known as 3D printing, is disrupting the automotive value chain and finding its way into more industrial processes. AM can now be used in numerous processes, says Sebastián Romo, CEO, Tridi. The automotive and aerospace industries have been the biggest adopters of 3D printing but the way the automotive sector uses this technology is changing. “OEMs are increasingly using this technology. Almost all OEMs in Mexico own a professional or an industrial (3D printing) machine.”

While AM’s adoption in the automotive sector is challenging due to cost factors, it is a useful tool during supply chain disruption times. “During assembly, AM helps to print all the needed components while the supply chain catches up. While 3D printing raises the price per piece, it prevents supply chains from stopping,” said to MBN Adi Fabro, Director of Automotive Business, Stratasys.

The potential of AM is significant. In the future, vehicle bodies could become 3D-printed, enabling not only lighter vehicles but a path to a future of rapid customization and personalization of cars, going from unique design to computer modeling and printing in days rather than years, according to the Society of Plastics Engineers. In the future, new companies could enter the automotive industry aiming to build 3D-printed cars that meet both government safety standards and consumer performance expectations.

Nanotechnology to Reinvent Material Technology  

As the automotive industry evolves, new technologies enter the sector to revolutionize it at different levels. Nanotechnology is currently being explored for diverse applications, from lightweight metal replacements to anti-corrosion performance and even battery production for BEVs.

Nanotechnology will be able to offer weight advancements while increasing the strength of vehicle parts. This would be achieved by embedding nanoparticles of metallic carbon nitride into metals as a way to increase the permanent strength of steel.

Innovation, advanced materials and nanotechnology are vital to move the industry forward, says Alex Elías Zúñiga, Research Group Leader of Nanotech and Device Designing, Tec de Monterrey. The academic sector is currently championing research, playing an important role in the industry’s transformation. However, further collaboration with the industry and government is needed to take the results from lab scale to mass production, said Zúñiga.

“Tec de Monterrey launched the Institute of Advanced Materials for Sustainable Manufacturing, where advanced materials are discovered, designed, manufactured, certified and scaled up from lab to mass production, aiming to develop lightweighting components for both the automotive and aerospace industries to reduce CO2 emissions,” said Zúñiga.