Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates
The optimization of elastocaloric cooling systems based on Shape Memory Alloys (SMAs) faces significant challenges in practical implementation. Despite promising thermomechanical properties, the development of efficient and compact cooling devices is hindered by incomplete understanding of strain ra...
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2025-04-01
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| author | Gianmarco Bizzarri Girolamo Costanza Ilaria Porroni Maria Elisa Tata |
| author_facet | Gianmarco Bizzarri Girolamo Costanza Ilaria Porroni Maria Elisa Tata |
| author_sort | Gianmarco Bizzarri |
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| description | The optimization of elastocaloric cooling systems based on Shape Memory Alloys (SMAs) faces significant challenges in practical implementation. Despite promising thermomechanical properties, the development of efficient and compact cooling devices is hindered by incomplete understanding of strain rate effects on transformation behavior and energy conversion efficiency. While previous research has broadly characterized general SMAs’ thermomechanical behavior, the specific relationship between strain rate and elastocaloric performance in Ni-Ti sheets requires systematic investigation to overcome these barriers. This study investigates the strain rate dependence of Ni-Ti sheets’ properties through systematic mechanical characterization across strain rates ranging from <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.56</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup><mspace width="3.33333pt"></mspace><msup><mi mathvariant="normal">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.15</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mspace width="3.33333pt"></mspace><msup><mi mathvariant="normal">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. Commercial Ni-Ti sheets underwent Shape Setting heat treatment and were characterized at eight different deformation levels using a universal testing machine equipped with a 50 kN load cell. Each deformation level was investigated through tests performed at four different crosshead speeds (1–24 mm/min), while monitoring stress-strain behavior and energy parameters. Results suggest distinct rate-dependent patterns in transformation stresses and energy dissipation characteristics across different strain rates. The analysis indicates that mechanical response and transformation behavior vary significantly between lower and higher strain rates, with implications for practical cooling applications. These findings aim to establish guidelines for optimizing elastocaloric performance by identifying suitable operating conditions for specific application requirements, considering factors such as energy conversion efficiency and cycling frequency. |
| format | Article |
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| institution | Kabale University |
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| spelling | doaj-art-88dee9cc234943daab2e55babbfe7ddb2025-08-20T03:26:56ZengMDPI AGCompounds2673-69182025-04-01521310.3390/compounds5020013Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain RatesGianmarco Bizzarri0Girolamo Costanza1Ilaria Porroni2Maria Elisa Tata3Industrial Engineering Department, University of Rome “Tor Vergata”, 00133 Rome, ItalyIndustrial Engineering Department, University of Rome “Tor Vergata”, 00133 Rome, ItalyIndustrial Engineering Department, University of Rome “Tor Vergata”, 00133 Rome, ItalyIndustrial Engineering Department, University of Rome “Tor Vergata”, 00133 Rome, ItalyThe optimization of elastocaloric cooling systems based on Shape Memory Alloys (SMAs) faces significant challenges in practical implementation. Despite promising thermomechanical properties, the development of efficient and compact cooling devices is hindered by incomplete understanding of strain rate effects on transformation behavior and energy conversion efficiency. While previous research has broadly characterized general SMAs’ thermomechanical behavior, the specific relationship between strain rate and elastocaloric performance in Ni-Ti sheets requires systematic investigation to overcome these barriers. This study investigates the strain rate dependence of Ni-Ti sheets’ properties through systematic mechanical characterization across strain rates ranging from <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.56</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup><mspace width="3.33333pt"></mspace><msup><mi mathvariant="normal">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>6.15</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mspace width="3.33333pt"></mspace><msup><mi mathvariant="normal">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>. Commercial Ni-Ti sheets underwent Shape Setting heat treatment and were characterized at eight different deformation levels using a universal testing machine equipped with a 50 kN load cell. Each deformation level was investigated through tests performed at four different crosshead speeds (1–24 mm/min), while monitoring stress-strain behavior and energy parameters. Results suggest distinct rate-dependent patterns in transformation stresses and energy dissipation characteristics across different strain rates. The analysis indicates that mechanical response and transformation behavior vary significantly between lower and higher strain rates, with implications for practical cooling applications. These findings aim to establish guidelines for optimizing elastocaloric performance by identifying suitable operating conditions for specific application requirements, considering factors such as energy conversion efficiency and cycling frequency.https://www.mdpi.com/2673-6918/5/2/13Shape Memory Alloyselastocaloric effectstrain rate sensitivityNi-Timechanical characterizationsuperelasticity |
| spellingShingle | Gianmarco Bizzarri Girolamo Costanza Ilaria Porroni Maria Elisa Tata Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates Compounds Shape Memory Alloys elastocaloric effect strain rate sensitivity Ni-Ti mechanical characterization superelasticity |
| title | Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates |
| title_full | Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates |
| title_fullStr | Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates |
| title_full_unstemmed | Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates |
| title_short | Mechanical Response and Elastocaloric Performance of Ni-Ti Shape Memory Alloy Sheets Under Varying Strain Rates |
| title_sort | mechanical response and elastocaloric performance of ni ti shape memory alloy sheets under varying strain rates |
| topic | Shape Memory Alloys elastocaloric effect strain rate sensitivity Ni-Ti mechanical characterization superelasticity |
| url | https://www.mdpi.com/2673-6918/5/2/13 |
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