Looking for a metal material that can remember its shape

[calaway]

I am looking for a material that can remember its original shape. It may change its shape under outside force, but can slowly restore its original shape. Sponge is a good example. However, I have more requirements.
1. It is a strong material like metal.
2. It has no harm to the body of human beings.
3. It can change its shape relatively quick after applying outside force (say pressing)
4. It will restore its original shape relatively slow after removing the outside force.

Could anybody please provide some advice?

Thank you!

 

[calaway]

I have formalized the requirements:

1. It is a strong material (for example it will change its shape only when you press it hard).

2. It has no harm to the body of human beings. For example, it can touch the skin for a long time and doesn't cause any itchy.

3. It can change its shape relatively quick after applying outside force (say pressing)

4. It will restore its original shape relatively slow after removing the outside force, say a few seconds, or a few tens of seconds. (must be slower than ordinary sponge and rubber back to their original shape).

Requirement 5 is actually optional.
5. Air can go though it (like a gauze), while the dust can be blocked.

 

[cloa]

Don't double post

 

[IRstuff]

These are all incredibly vague requirements.

"Strong" is not a technical term. Numerical values of hardness, or elasticity, etc., will get you meaningfull answers.

"Outside force" has no technical value. What numerical value of pressure or force? What numerical dimensions? How much numerical compression?

What numerical dust size ?

TTFN

FAQ731-376

 

[gariartola]

The only metallic shape memory alloys I have heard of work on a temperature activated metallographic change basis and not on a viscoelastic behaviour basis as the sponges.
I would say try PE coated Nitinol, since nitinol would intereact withthe skin as it is 50% Nickel, you would need a biocompatible barrier as PE that is flexible enough no stand the deformation.
Follow this links to get to nice collection of related links:

http://www.smaterial.com/SMA/link/link.html