BY SYNDICATE NO 2

INTRODUCTION WHAT ARE SHAPE MEMORY ALLOYS.

MATERIALS WHICH REMEMBERS ITS SHAPE.

COMMONLY KNOWN AS SMA.

AFTER IT IS DEFORMED, IT REGAINS ITS

ORIGINAL GEOMETRY BY ITSELF DURING

HEATING (ONE-WAY EFFECT) OR, AT HIGHER

AMBIENT TEMPERATURES, SIMPLY DURING

UNLOADING (PSEUDO-ELASTICITY).

RAPIDLY FINDING ITS PLACE IN MOST OF

THE INDUSTRIES.

FURTHERANCE OF PHASE TRANSFORMATION

KNOWLEDGE.

PHASES

PH 1 : BRIEF ON SMA.

PH 2 : THEORY BEHIND SMA.

PH 3 : SHAPE MEMORY EFFECT & PSEUDO-

ELASTICITY.

PH 4 : APPLICATIONS OF SMA.

CONCLUSION.

BRIEF ON SMA

METALS THAT REMEMBER ITS ORIGINAL SHAPE.

EXHIBIT TWO UNIQUE PROPERTIES :-

PSEUDO-ELASTICITY.

SHAPE MEMORY EFFECT.

ARNE OLANDER FIRST OBSERVED THESE

UNUSUAL PROPERTIES IN 1938, BUT NOT UNTIL THE

1960'S WERE ANY SERIOUS RESEARCH ADVANCES

MADE IN THE FIELD OF SHAPE MEMORY ALLOYS.

BRIEF ON SMA DIVERSE APPLICATIONS MADE THEM INCREASINGLY IMP & VISIBLE TO THE WORLD.

NITINOL OR NICKEL-TITANIUM ALLOY MOST IMP.

NITINOL IS Ni-Ti NAVAL ORD LABARATORY.

SHAPE MEMORY PROPERTY OF NITINOL WAS DISCOVERED BY ACCIDENT.

AT A LABORATORY MANAGEMENT MEETING, A

STRIP OF NITINOL WAS PRESENTED THAT WAS BENT OUT

OF SHAPE MANY TIMES. ONE OF THE PEOPLE PRESENT, DR.

DAVID S. MUZZEY, HEATED IT WITH HIS PIPE LIGHTER,

AND SURPRISINGLY, THE STRIP STRETCHED BACK TO

ITS ORIGINAL FORM.

THEORY BEHIND SMA HOW DOES SMA “REMEMBERS” ITS SHAPE WAS THE

QUESTION AFTER ITS DISCOVERY.

THIS OCCURS DUE TO SOLID STATE PHASE CHANGE.

TYPICALLY WHEN ONE THINKS OF A PHASE CHANGE A

SOLID TO LIQUID OR LIQUID TO GAS CHANGE IS THE

FIRST IDEA THAT COMES TO MIND. A SOLID STATE

PHASE CHANGE IS SIMILAR IN THAT A MOLECULAR

REARRANGEMENT IS OCCURRING, BUT THE

MOLECULES REMAIN CLOSELY PACKED SO THAT THE

SUBSTANCE REMAINS A SOLID.

PHASES INVOLVED ARE AUSTENITE AND

MARTENSITE.

THEORY BEHIND SMA INVOLVES THE REARRANGEMENT OF THE POSITION

OF PARTICLES WITHIN THE CRYSTAL STRUCTURE

OF THE SOLID.

TRANSITION TEMP OF THESE PHASES IS VERY LOW.

THE TRANSITION TEMPERATURE VARIES FOR

DIFFERENT COMPOSITIONS FROM ABOUT -50 ° C TO 166 ° C.

BELOW TRANSITION TEMP IS MARTENSITE AND

ABOVE IT IS AUSTENITE.

IN THE MARTENSITE PHASE, NITINOL CAN BE BENT

INTO VARIOUS SHAPES.

THEORY BEHIND SMA TO FIX THE "PARENT SHAPE" (AS IT IS CALLED), THE

METAL MUST BE HELD IN POSITION AND HEATED TO

ABOUT 500 ° C.

THE HIGH TEMPERATURE CAUSES THE ATOMS TO

ARRANGE THEMSELVES INTO THE MOST COMPACT

AND REGULAR PATTERN POSSIBLE RESULTING IN A

RIGID CUBIC ARRANGEMENT KNOWN AS THE

AUSTENITE PHASE.

ABOVE THE TRANSITION TEMPERATURE, NITINOL

REVERTS FROM THE MARTENSITE TO THE AUSTENITE

PHASE WHICH CHANGES IT BACK INTO ITS PARENT

SHAPE. THIS CYCLE CAN BE REPEATED MILLIONS OF

TIMES.

SHAPE MEMORY EFFECT TRANSITION TEMP DEPENDS UPON THE

COMPOSITION OF THE ALLOY.

THE TEMPERATURES AT WHICH EACH OF THESE

PHASES BEGIN AND FINISH FORMING ARE

REPRESENTED BY VARIABLES : MS, MF, AS, AF.

MS & MF ARE START & FINISH TEMP OF AUSTENITE

TO MARTENSITE TRANSFORMATION.

AS, AF ARE START & FINISH TEMP OF MARTENSITE

TO AUSTENITE TRANSFORMATION.

WHEN THE ALLOY IS COOLED BELOW THE

TRANSITION TEMP IT TAKES THE TWINNED MARTENSITE

STRUCTURE.

SHAPE MEMORY EFFECT

HAS SAME SHAPE AND SIZE AS AUSTENITE SO NO

VISIBLE DIFFERENCE OBSERVED UNLESS ITS

DEFORMED/LOADED

WHEN DEFORMED IT TAKES THE DESIRED SHAPE

IF ALLOY HEATED ABOVE TRANSITION TEMP;

TAKES THE PREVIOUS SHAPE IN AUSTENITE

STRUCTURE

SHAPE MEMORY EFFECT

SHAPE MEMORY EFFECT

SHAPE MEMORY EFFECT

PSEUDO-ELASTICITY

PSEUDO-ELASTICITY OCCURS IN SHAPE MEMORY

ALLOYS WHEN THE ALLOY IS COMPLETELY

COMPOSED OF AUSTENITE.

UNLIKE THE SHAPE MEMORY EFFECT, PSEUDO-

ELASTICITY OCCURS WITHOUT A CHANGE IN

TEMPERATURE.

PSEUDO-ELASTICITY THE LOAD ON THE SHAPE MEMORY ALLOY IS

INCREASED UNTIL THE AUSTENITE BECOMES

TRANSFORMED INTO MARTENSITE SIMPLY DUE TO

THE LOADING.

THE LOADING IS ABSORBED BY THE SOFTER

MARTENSITE, BUT AS SOON AS THE LOADING IS

DECREASED THE MARTENSITE BEGINS TO TRANSFORM

BACK TO AUSTENITE SINCE THE TEMPERATURE OF

THE WIRE IS STILL ABOVE AF, AND THE WIRE SPRINGS

BACK TO ITS ORIGINAL SHAPE.

PSEUDO-ELASTICITY

Load Diagram of the pseudo-elastic effect Occurring

PSEUDO-ELASTICITY

APPLICATIONS OF SMA

AERONAUTICAL APPLICATIONS.

AIRCRAFT MANEUVERABILITY DEPENDS

HEAVILY ON THE MOVEMENT OF FLAPS

FOUND AT THE REAR OR TRAILING EDGE OF THE

WINGS.

MOST AIRCRAFT IN THE AIR TODAY

OPERATE THESE FLAPS USING EXTENSIVE

HYDRAULIC SYSTEMS. THIS COMPLEX SYSTEM

OF PUMPS AND LINES IS OFTEN RELATIVELY

DIFFICULT AND COSTLY TO MAINTAIN.

APPLICATIONS OF SMA

AERONAUTICAL APPLICATIONS.

THE SHAPE MEMORY WIRE IS USED TO

MANIPULATE A FLEXIBLE WING SURFACE.

THE SHAPE MEMORY EFFECT IS INDUCED

IN THE WIRES SIMPLY BY HEATING THEM WITH

AN ELECTRIC CURRENT, WHICH IS EASILY

SUPPLIED THROUGH ELECTRICAL

WIRING, ELIMINATING THE NEED FOR LARGE

HYDRAULIC LINES.

APPLICATIONS OF SMA

Hinge less shape memory alloy Flap

Typical Wing and Flap

APPLICATIONS OF SMA MEDICAL APPLICATIONS

REPAIRING FRACTURES

ORTHODONTIC TREATMENTS

TWEEZERS

MUSCLE WIRES IN ROBOTICS INDUSTRY

FIRE SPRINKLERS

FUTURE APPLICATIONS

USE OF MECH ENERGY FROM SHAPE TRANSFORMATION IN CAR ENGINES

ENGINE COOLING

LUBRICATION CONTROL

CONTROL OF RADIATOR BLIND

APPLICATIONS OF SMA

CONVENTIONAL BONE PLATE USED TO REPAIR JAW FRACTURE

TYPICAL OSTEOSYNTHESIS

TOOLS

APPLICATIONS OF SMA

EVEN A BADLY FRACTURED FACE CAN BE RECONSTRUCTED USING BONE PLATES

APPLICATIONS OF SMA

USE OF SMA IN ROBOTICS INDUSTRY

APPLICATIONS OF SMA

CONCLUSION

USES & APPLICATION ENSURE BRIGHT FUTURE OF

THESE ALLOYS

RESEARCH AT ROBOTICS & MAT SC DEPARTMENTS

ALL OVER THE WORLD

INNOVATIVE IDEAS FOR USING SMA

USE OF SMA IN VAST NO OF FIELDS ENSURES IT

PROMISING FUTURE.