How do Memory Metals work?

I found this site that describes how they work. What I am hoping to find is somebody who can “dumbdown” the technobabble for me.
Austenite and Martensite are not terms that I am using my daily conversations.

Is the “memorized” form only able to be created when the metal is cast?
How do memory metals get “amnesia”?

The link to the page that lists markets for memory metals is a dead end, so what are its applications other than eyeglass frames?


*“Shape Memory Alloys (SMAs) refer to a group of materials which have the ability to return to a predetermined shape when heated. The shape memory effect is caused by a temperature dependent crystal structure. When an SMA is below its phase transformation temperature, it possesses a low yield strength crystallography referred to as Martensite (see Stress-Strain figure). While in this state, the material can be deformed into other shapes with relatively little force. The new shape is retained provided the material is kept below its transformation temperature. When heated above this temperature, the material reverts to its parent structure known as Austenite causing it to return to its original shape” *
etc etc

Shape Memory Alloys (SMA’s) are novel materials which have the ability to return to a predetermined shape when heated. When an SMA is cold, or below its transformation temperature, it has a very low yield strength and can be deformed quite easily into any new shape–which it will retain. However, when the material is heated above its transformation temperature it undergoes a change in crystal structure which causes it to return to its original shape. If the SMA encounters any resistance during this transformation, it can generate extremely large forces. This phenomenon provides a unique mechanism for remote actuation.
etc etc
and just for kicks here some shape memory plastics