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Shape_Memory_Alloys_Seminar_Technical.pptx
- 1. Shape Memory Alloys ASeminar Presentation Department of Mechanical Engineering January 2026
- 2. Outline • Introduction toShape Memory Alloys – Types and Mechanism – Properties and Processing – Applications – Advantages and Limitations – Research Gaps and Objectives – Conclusions – Future Scope – References
- 3. Introduction • Shape MemoryAlloys (SMAs) are smart materials that can recover their original shape after deformation. – This behavior occurs due to a reversible solid-state phase transformation. – Commonly used in engineering, medical and aerospace systems.
- 4. Basic Concept ofSMAs • Two main phases: Austenite (high temperature) and Martensite (low temperature). – Shape memory effect and superelasticity are key phenomena. – Thermo-mechanical coupling governs their behavior.
- 5. Types of ShapeMemory Alloys • Nickel-Titanium (NiTi) alloys – Copper-based alloys (Cu-Zn-Al, Cu-Al-Ni) – Iron-based alloys (Fe-Mn-Si) – High temperature SMAs
- 6. Shape Memory Effect •One-way shape memory effect – Two-way shape memory effect – Transformation induced by temperature change. – Applications in actuators and sensors.
- 7. Superelasticity • Occurs whenalloy is deformed above transformation temperature. – Large recoverable strains (up to 8%). – Used in orthodontic wires and flexible structures.
- 8. Properties of SMAs •High damping capacity – Excellent corrosion resistance – Good biocompatibility (especially NiTi) – High fatigue resistance
- 9. Processing of SMAs •Melting and casting – Thermo-mechanical treatment – Heat treatment for phase stabilization – Additive manufacturing of SMAs
- 10. Applications of ShapeMemory Alloys • Biomedical: stents, orthodontic wires, surgical tools – Aerospace: adaptive wings, vibration control – Robotics: actuators and artificial muscles – Civil engineering: seismic dampers
- 11. Advantages • High actuationforce to weight ratio – Simple mechanical design – Silent operation – Self-adaptive behavior
- 12. Limitations • High materialcost – Limited actuation frequency – Fatigue life under cyclic loading – Complex material behavior modeling
- 13. Research Gaps • Limitedunderstanding of long-term fatigue behavior – Challenges in large-scale manufacturing – Need for improved high-temperature SMAs – Integration with smart systems
- 14. Objectives of PresentStudy • To understand phase transformation mechanisms in SMAs – To analyze mechanical and thermal properties – To study application potential in engineering systems – To identify future research directions
- 15. Conclusions • Shape MemoryAlloys are unique smart materials with wide engineering applications. – Their behavior is governed by reversible martensitic transformation. – Despite limitations, SMAs continue to gain importance in advanced technologies.
- 16. Future Scope • Developmentof low-cost SMAs – Improvement in fatigue resistance – Advanced modeling and simulation techniques – Integration with IoT and smart structures
- 17. References • Otsuka, K.,Wayman, C.M., Shape Memory Materials, Cambridge University Press. – Lagoudas, D.C., Shape Memory Alloys: Modeling and Engineering Applications. – Jani et al., A review of shape memory alloys, Materials & Design, 2014. – Duerig et al., Engineering Aspects of Shape Memory Alloys.
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- 20. Thermodynamics of SMAs •Martensitic transformation is diffusionless and reversible. – Driving force is free energy difference between phases. – Transformation temperatures depend on composition and heat treatment. – Clausius–Clapeyron relation links stress and transformation temperature.
- 21. Constitutive Modeling ofSMAs • Phenomenological models: Tanaka, Liang– Rogers, Brinson models. – Micromechanical models based on phase fraction evolution. – Key variables: stress, strain, temperature, martensite fraction. – Used for actuator and smart structure design.
- 22. Fatigue and Functional Degradation •Thermo-mechanical cycling leads to functional fatigue. – Causes: dislocation accumulation, phase stabilization. – Design must consider transformation stability. – Surface treatments improve fatigue life.