Scientists from the U.S. Department of Energy’s Ames Laboratory are developing a new technique for evaluating the strength of powdered metals.

Jim Foley, associate scientist at Ames Lab, said powdered metals are used for automobile parts such as steering columns and mountings for rear-view mirrors. They are also used in gears, blenders and other parts.

Powder metallurgy (P/M) involves a process known as “sintering,” in which powdered metal is pressed and heated until the powder particles are bonded together in a solid mass, Foley said.

He said the conventional method for evaluating the effectiveness of the sintering process is trial and error.

“It’s kind of a guessing process. You have to heat the metal up and try different kinds of conditions, then cool it down to see if it worked,” he said. “Our technique can watch the powders bond together as the sintering is happening.”

Foley and Ames Lab assistant scientist Dave Rehbein developed the ultrasonic, non-destructive technique, which uses an electromagnetic acoustic transducer (EMAT).

Rehbein said the EMAT could provide manufacturers with a method for inspecting their parts quickly and efficiently.

“There are very few ways to inspect parts as they are being produced, and inspection is becoming more and more important these days,” he said. “[Manufacturers] want to cut down on waste and increase efficiency. What we have developed is a technique we can use to monitor the processing of a part to make sure that before it goes into service, it is of the quality required.”

Foley said he was confident the new evaluation method was working when he saw a strong correlation between the measured output the EMAT produced and the actual strength of the metals that were evaluated.

“The data showed a very strong correlation,” he said. “We’ve gotten some unexpected, but very good, results.”

Foley said he and Rehbein began developing the EMAT technique about a year ago.

“I just had this idea that it might work, and so far it is,” he said, “and we’re just in the initial stages.”

Even though the technique is in early development, Foley said he was optimistic the new method could become commonplace in the future.

“I think it will become widespread in the field of manufacturing parts,” he said.

Rehbein said he thought the EMAT method would probably be used to help further the development of powder metallurgy.

“P/M is still developing as a technology itself,” he said. “Down the road, this technique might allow us to create new and different alloy blends that haven’t been made yet.”