Skip to Content

Attractive Shapes

Materials: Magnetically controlled metal could yield better machine parts.

Materials scientists have long played with “shape memory alloys,” metals that shift between one shape and another when heated or cooled to just the right temperature. But so far, real-world applications have been limited, because controlling the alloy’s shape with temperature is often difficult and inefficient. Now, researchers have found a way to accomplish the same shape-memory tricks using magnets rather than temperature-an advance that could make possible efficient, less clunky moving parts for machine components in aircraft, automobiles or even robots.

Materials scientists Bob O’Handley of MIT and Kari Ullakko from the Helsinki University of Technology in Finland reasoned that an alloy of nickel, manganese and gallium might respond to a magnetic field with a change of shape. When the researchers expose a sample of the new alloy to a magnetic field about two or three times stronger than that generated by a refrigerator magnet, the material becomes rubbery and expands. When the researchers remove the field, a spring pushing on the alloy causes it to revert to its original shape. By alternating the magnetic field at high speed, the researchers can repeat the cycle several thousand times per minute. “It sort of looks like a heart beating very quickly,” says O’Handley.

Adding magnetic control, researchers believe, will make shape memory alloys much more practical to use. “There’s a great deal of promise in these [magnetically controlled] materials,” says the University of Minnesota’s Thomas Shield, who also studies shape memory alloys. O’Handley, for example, envisions using the alloy to make lightweight mechanical parts in airplane wing flaps. A lump of the new material wrapped in a magnetic coil could raise and lower a flap on cue, replacing today’s heavy hydraulic systems that require a central pump and multiple oil lines running to the flaps.

O’Handley and his crew have also partnered with two engineering firms in the Boston area-Mid Technology and ACX-that manufacture valves and pumps for automotive and aerospace applications, among other uses. The researchers aim to have a working prototype of a generic pump ready before the end of this year. The MIT scientists are also working with four other universities to make a magnetic shape memory material that combines the metal alloy with a polymer. If it works, it could lead to an even lighter and cheaper “beating heart.”

Keep Reading

Most Popular

Large language models can do jaw-dropping things. But nobody knows exactly why.

And that's a problem. Figuring it out is one of the biggest scientific puzzles of our time and a crucial step towards controlling more powerful future models.

OpenAI teases an amazing new generative video model called Sora

The firm is sharing Sora with a small group of safety testers but the rest of us will have to wait to learn more.

Google’s Gemini is now in everything. Here’s how you can try it out.

Gmail, Docs, and more will now come with Gemini baked in. But Europeans will have to wait before they can download the app.

This baby with a head camera helped teach an AI how kids learn language

A neural network trained on the experiences of a single young child managed to learn one of the core components of language: how to match words to the objects they represent.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.