Termostressi

Termostressi, also known as thermoelastic martensitic transformation, is a phenomenon observed in certain alloys, particularly those containing nickel and titanium. These alloys exhibit a unique property where they can undergo a reversible phase transformation between two crystal structures, austenite and martensite, in response to temperature changes. This transformation is driven by the thermoelastic effect, where the change in temperature causes a change in the crystal structure without the need for diffusion of atoms.

The transformation occurs at a specific temperature, known as the transformation temperature, which can be influenced by factors such as alloy composition, heat treatment, and mechanical stress. When the alloy is heated above the transformation temperature, it transforms from martensite to austenite, which is a more symmetrical crystal structure. Conversely, when the alloy is cooled below the transformation temperature, it transforms from austenite to martensite, which is a less symmetrical crystal structure.

Termostressi is utilized in various applications, including actuators, sensors, and medical devices. The transformation induces significant shape changes and stress, making these alloys suitable for applications requiring precise control of movement or sensing of temperature changes. The reversible nature of the transformation allows for repeated cycles of shape change and recovery, making these alloys highly reliable for dynamic applications.