Flexible and shape memory ceramic

Shape memory materials are capable of taking two different forms and can alternate between one and the other as long as the necessary conditions are met. The shape change can be triggered by a suitable change in temperature, by a specific mechanical stress, or by electric or magnetic fields. The change in shape can serve for the material to exert a mechanical force.

The value of shape-memory materials is that they are a kind of solid-state piston, that is, a device that can push something else. But while a piston is an assembly of many parts, a shape memory material does it all by itself, without needing multiple parts.

Shape memory metals have long been used as simple actuators in a wide range of devices, but are limited by the achievable service temperatures of the metals used, which are typically a few hundred degrees Celsius at most.

Ceramic can withstand much higher temperatures, sometimes up to thousands of degrees, but unfortunately it is very brittle, breaking very easily.

Now, scientists have found a way to overcome this typical drawback of ceramics and create a new class of shape-memory ceramic materials that can withstand changes without accumulating damage, thus making it possible for them to function reliably as shape-memory material. shape over many cycles of use.

The diagrams show the two different ways in which the atomic structure of the new shape memory ceramic material can be configured. An external trigger, such as a change in temperature, can change the configuration from one shape to another, changing its dimensions and allowing it to exert pressure or do other work. The background of the image is an electron microscope photo showing some details of the material’s structure, with the two colors indicating the two different configurations. (Image: Edward Pang. CC BY-NC-ND 3.0)

These new, shatter-resistant, shape-memory ceramics could be useful for a new range of applications, especially in high-temperature environments, such as acting as actuators inside a fully-functioning jet engine or at the bottom of a very deep well, where the temperature is also very high.

This research and development work is the work of the team of Edward Pang, Gregory Olson and Christopher Schuh, from the Department of Materials Science and Engineering at the Massachusetts Institute of Technology (MIT), in the United States. And it has had the backing of the United States Army. (Font: NCYT by Amazings)