Researchers at the Worcester Polytechnic Institute (WPI) are testing a new type of welding that has the potential to be more resistant to corrosion, according to the school's website. The technique, called friction stir welding, has a potential application in automobile production, where it would be used to create metal joints that more effectively withstand salt spray and other problems on the road.
The research is being led by WPI Associate Professor Adam Powell. Powell and his team of fellow professors and postdoctoral and PhD students put welded joints through a cyclic corrosion test chamber and use a computer program to monitor the results.
"We're trying to show that corrosion can be much less of a problem with this new type of welding," said Powell, speaking with WPI's media team.
Over the course of the experiment, the tested welds will crisscross the country and sit in three separate laboratories. Before Powell and the WPI team's testing can begin, scientists thousands of miles away at the Pacific Northwest National Laboratory (PNNL) in Washington state perform friction stir welding on lightweight aluminum and magnesium. Once welded, the materials are shipped to Worcester, where Powell begins his testing.
Ultimately the hope is that friction stir welding can be used to create joints that will withstand tough winter conditions and last for up to 20 years with minimal corrosion.
The welds are put in rows in a cyclic corrosion test chamber, a three foot tall isolated space, and exposed to everything from salt spray to temperatures as high as 140 degrees. Each test is designed to rapidly simulate a naturally occurring process that could cause corrosion. Using a wide variance of stimuli on the welds is important because it simulates the full life cycle of a car.
"It's that cycling between different conditions that leads to accelerated corrosion," said Powell.
From there, Powell and his team collect data and use it to create a computer simulation, designed to show corrosion and mechanical failure over the joint's lifespan. Once testing is complete, corroded welds are sent in to the Oak Ridge National Laboratory (ORNL) in Tennessee, for more advanced analysis.
The experiment is funded for a three-year period, with each year meant to be used to look at a different factor. According to Powell, the first year will focus on examining the corrosion created by the magnesium and aluminum parts, while the second will be for simulating corrosion on the welds themselves. The third and final year is meant to give time to make sure the models are as accurate as possible. The funding for all three labs was provided through a grant from the Department of Energy's Office of Energy Efficiency and Renewable Energy's Vehicle Technologies Office. The total grant is for $1.5 million, of which WPI researchers, as the lead group, will take about half.
"This Process Holds A Lot of Promise"
Because Powell's research has the potential to improve automobile designs, industry leaders have also provided support for the testing. The Canadian auto-tech company Magna International Inc., for example, is contributing the magnesium and aluminum parts that researchers are welding together, as well as in-kind time. Powell sees friction stir welding as having the potential to make automobiles last longer, a positive development for both manufacturers and consumers.
"We think that this process holds a lot of promise and could make a significant impact on energy use in motor vehicles without reducing the lifespan of a car," said Powell.
According to a report from The Welding Institute (TWI), friction stir welding was first developed back in 1991 but has become increasingly common in the automotive industry in recent years. In particular, the technique is often used for welds involving aluminum and other lighter metals. Testing the technique's ability to withstand corrosion is an important step in its continued implementation.
Ultimately, for Powell, the hope is that his testing shows that friction stir welding can be used to create joints that will withstand tough winter conditions and last for up to 20 years with minimal corrosion. The joints would most likely be used in car doors, but could have applications throughout the body of a car. In addition to lasting longer, joints, and the materials around them, could become lighter, making the car more efficient.
"All of these benefits will go a long way to impacting the safety, performance, and lifespan of a car," said Powell via the WPI website.