Elastocaloric effect vs fatigue life : exploring the durability limits of Ni-Ti plates under pre-strain conditions for elatocaloric coolling

Tušek, Jaka (avtor), Žerovnik, Andrej (avtor), Čebron, Matjaž (avtor), Brojan, Miha (avtor), Žužek, Borut (avtor), Engelbrecht, Kurt (avtor), Cadelli, Andrea (avtor)

Structural fatigue is the major obstacle that prevents practical applications of the elastocaloric effect (eCE) in cooling or heat-pumping devices. Here, the eCE and fatigue behaviour of Ni-Ti plates are systematically investigated in order to define the fatigue strain limit and the associated eCE. Initially, the eCE was evaluated by measuring adiabatic temperature changes at different strain amplitudes and different mean strains along the loading and unloading transformation plateaus. By comparing the eCE with and without pre-strain conditions, the advantages of cycling an elastocaloric material at the mean strain around the middle of the transformation plateau were demonstrated. In the second part of this work, we evaluated the fatigue life at the mean strain of 2.25% at the loading plateau and at the unloading plateau after initial pre-straining up to 6% and 10%, respectively. It is shown that on polished samples, durable operation of 10 5 cycles can be reached with a strain amplitude of 0.50% at the loading plateau, which corresponds to adiabatic temperature changes of approximately 5 K. At the unloading plateau (after initial pre-strain of 10%), durable operation was reached at a strain amplitude of 1.00%, corresponding to adiabatic temperature changes of approximately 8%K. The functional fatigue was analysed after the cycling and it is shown that once the sample has been stabilized there is no further degradation of the eCE, even after 10 5 cycles. These results present guidelines for the design and operation of efficient and durable elastocaloric devices in the future.

• Jezik: Angleški jezik
• Ključne besede: elastocaloric effect, shape memory materials, Ni-Ti, fatigue, strain
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Recenzirani rokopis
• Leto izida: 2018
• Št. strani: Str. 295-307
• Številčenje: Vol. 150
• PID: 20.500.12556/RUL-127889
• UDK: 621.56(045)
• ISSN pri članku: 1359-6454
• DOI: 10.1016/j.actamat.2018.03.032
• COBISS.SI-ID: 15964187
• Datum objave v RUL: 28.06.2021

Gradivo je del revije

• Naslov: Acta materialia
• Skrajšan naslov: Acta mater.
• Založnik: Elsevier Science
• ISSN: 1359-6454
• COBISS.SI-ID: 16852229

Licence

• Licenca: CC BY-NC-ND 4.0, Creative Commons Priznanje avtorstva-Nekomercialno-Brez predelav 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc-nd/4.0/deed.sl
• Opis: Najbolj omejujoča licenca Creative Commons. Uporabniki lahko prenesejo in delijo delo v nekomercialne namene in ga ne smejo uporabiti za nobene druge namene.
• Začetek licenciranja: 22.03.2018

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: elastokalorični učinek, zlitine z oblikovnim spominom, Ni-Ti, utrujanje, deformacije

Projekti

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: Z2-7219
• Naslov: Od elastokaloričnega efekta do učinkovite hladilne naprave