Shape memory alloy, application of shape memory alloy, need for the shape ,memory alloy, recent advantages in the materials , Nasa new material for MARS rovers

1. Shape Memory Alloys
By: SIDDESH KUMAR N M 180939013

2. Mars Rovers
Curiosity Rover
Launched Nov 2011
By NASA
Still operating
Travelled 20km
Speed .14 km/hour
Opportunity Rover
Launched July 2013
By NASA
ceased 2018
Travelled 45km
Speed 1 km/hour

3. LUNOKHOD 2
Moon walker
Launched in 1973 by Russia
Travelled 39 km
Wheels made up of aluminum
Speed of the rover is 1 - 2km/hour

4. Distance travelled by different rovers

5. What is the main reason
the failure of rovers

6. Wheels are made up of Nickel Titanium Alloy

7. Shape
memory alloys
 Shape Memory Alloys (SMAs) are metallic alloys that undergo a
solid-to-solid phase transformation which can exhibit large
recoverable strains.
 The two most prevalent shape-memory alloys are
 Copper-aluminium-nickel
 Nickel-titanium (Ni Ti)
 Iron and copper based shape memory alloys
 Fe-Mn-Si
 Cu-Zn-Al
 Cu-Al-Ni

8. Properties of Nickel & Titanium
Properties Nickel Titanium
Density 8.908 g/cm3 4.197 g/cm3
Melting point 1455 °C 1668 °C
Magnetic property Ferro magnetic Para magnetic
Young's modulus 200 GPa 116 GPa
Shear modulus 76 GPa 44 GPa
Bulk modulus 180 GPa 110GPa
At elevated temperature and
pressure
Will remain same Will change the properties
Application Can be used at high temperature
& high pressure
Cannot be used at high
temperature

9. Austenite
 High temperature phase
 Cubic Crystal Structure
Martensite
 Low temperature phase
 Monoclinic Crystal Structure
Twinned Martensite Detwinned Martensite
Crystal structure

10. Mf Ms As Af
Austenite
Martensite TEMPERATURE
Mf Ms As Af
Austenit
e
Martensite TEMPERATURE
(twinned)
(twinned)
Phase Transformation

11. Machining
 Nitinol is a very abrasive material to machine due
to its tough titanium oxide surface.
 Milling, turning, and grinding are possible with
excellent results, but expect a lot of tool wear.
 Carbide tooling is highly recommended.
 Nitinol can be electrical discharge machined
(EDM), water-jet cut, and laser machined with
excellent results

12. Cold working
Nitinol wire and tube typically will have 30-40%
cold work reduction during the last drawing
steps.
In sheet and strip products, that value is usually
closer to 20% reduction. The amount of cold
work a material has prior to its shape set anneal
decides the ultimate strength of the material.
Nitinol in the cold work condition (as drawn or
as rolled) is material that has not been subject
to a final heat treatment (shape set anneal).

13. Surface finish
Mechanically polished surface
Nitinol wire and strip is abrasively polished to a shiny,
bright surface prior to straightening.
This surface looks very similar to stainless steel and is
very popular for its cosmetic appeal.
A centreless grinding method is applied to Nitinol wire
and tubes to achieve a bright surface
Coatings
Nitinol can be coated with polymers such as
polyurethane and Teflon.
Polyurethane extruded over Nitinol is common for cell
phone antennas.
Teflon extrusion and spray coating of Nitinol is becoming
more common today.

14. Joining to
Nitinol
Soldering: Sn-Ag solder can be used
Welding: Laser, TIG, and resistance welding
A Nitinol tube connector can be expanded
either mechanically or by cooling it to
martensite and deforming it.
The Nitinol connector is then inserted over
another element and allowed to return to
austenite, causing it to clamp down on the
element.

15. Beneficial Properties of Ni Ti SMAs
Ductility is improved
Excellent corrosion resistance
(comparable to 300 stainless steel)
Stable transformation temperature
High biocompatibility
More recoverable motion
Adding alloying element 1% change
mechanical property and phase
transformation temperature.
Fe and Cr can added to lower the
Transformation temperature

16. Applications
• Aero space
• Space vehicle
• Bio medical
• Automobile
• Actuators

17. Nickel Titanium Alloy

18. Thank you …….
Any queries ….????