1. SMART MATERIALS

2. Introduction:- Nature is full of magic materials. Nature is full of magic materials. Smart materials can sense, stimulate, process and actuate a response. Smart materials can sense, stimulate, process and actuate a response. the properties can be easily altered. the properties can be easily altered.

3. Shape memory alloys (SMA’s):- Metals which exhibit 2 unique properties: (1) Pseudo-elasticity. (2) Shape Memory Effect.

4. Working of SMA’s:- The properties are due to the solid state phase change. There are two phases:- (1) Marten site and (2) Austenite.

5. Marten site is relatively soft and exist at low temp’s The molecular structure is as below:

6. ► Austenite is the stronger phase, occurs at high temp’s. ► Cubic structure.

7. Shape Memory Effect:- The un-deformed marten site and the austenite have same size and shape. Shape memory effect is absorbed when it is cooled down to less than M f.

8. Pseudo Elasticity:- It occurs in the alloys which completely consists of Austenite. It occurs without a change in temperature. Applications of pseudo elasticity: (1) eyeglass frames. (2) orthodontic arches.

9. Applications of shape memory alloys:-  I I I In air craft maneuverability.

10.  In Robotic muscles:

11. Points of consideration:- (1) The method of controlling movement with the limb. (2) Emulating real human movements. (3) The gripping force required to hold any object.

12.  Creating human motion using SMA wires is a complex task.  The wire is heated by passing the current through it.

13.  In Bone plates:

14. advantages of sma:- advantages of sma:- Bio-compact ability Bio-compact ability Good Mechanical properties. Good Mechanical properties. dis-advantages of sma:- dis-advantages of sma:-  These alloys are expensive.  poor fatigue properties

15. Conclusion:- ►T►T►T►The SMA’s have a major say in the field of precision engineering. ►T►T►T►These play a vital role in the surgical operations. ►T►T►T►These act as best alternatives in the field of manufacturing.

16. References:- o Material Science and Manufacturing by M.Moallem. o Material Science and Engineering by K.M.Guptha, Umesh Publications. o Elements of Material Science and Engineering by Van vik / Adison Wesley.