How do you use a shape memory alloy?

Bend an object made from shape-memory alloy and you deform its internal crystalline structure. Let it go and it stays as it is, permanently bent out of shape. Now apply some heat and the crystalline structure inside changes into an entirely different form, prompting the object to revert back to its original shape.

How does the shape memory effect work?

One-way memory effect When a shape-memory alloy is in its cold state (below As), the metal can be bent or stretched and will hold those shapes until heated above the transition temperature. Upon heating, the shape changes to its original. When the metal cools again, it will retain the shape, until deformed again.

How does Nitinol shape memory work?

Shape memory alloys, such as nickel titanium, undergo a phase transformation in their crystal structure when cooled from the stronger, high temperature form (austenite) to the weaker, low temperature form (martensite).

How do you train SMA wire?

Shape Memory Alloy Training

1. Step 1: Fix SMA into the shape you want. As you heat the SMA, it will move to the shape it was memorized for the last.
2. Step 2: Heat it up to 400 degrees for 8-10min.
3. Step 3: Drop it quickly into cold water.
4. Step 4: Take it out from the fixing tool and test.

Can you retrain a sample of nitinol with hot water?

Avoid touching the top or sides of the hot plate with your body or with the cord on the Vernier temperature probe. When immersing the nitinol wire in hot water or retraining the wire in a flame, make sure that you always hold on to the wire in such a way that you avoid burning your fingers and hands.

How do you train SMA?

How do you set the shape of nitinol?

In general, temperatures as low as 400 deg. C and times as short as 1-2 minutes can set the shape, but generally one uses a temperature closer to 500 deg. C and times over 5 minutes. Rapid cooling of some form is preferred via a water quench or rapid air cool (if both the parts and the fixture are small).

What is shape memory alloys effect?

Shape memory effect (SME) alloys involve a thermoelastic martensitic transformation in which martensite plates form and grow continuously as the temperature is lowered below Ms and disappear by the same reverse path when the temperature is raised.

How do you train Nitinol?

What phase of nitinol is rigid?

Slide 14 (Austenite phase of Nitinol): The high temperature phase of Nitinol is called Austenite. In this phase, the alloy is rigid and has a defined shape.