Lee H.-CShen J.-JChang Y.-TWu C.-TCHIH-HSUAN CHEN2022-03-222022-03-22202209258388https://www.scopus.com/inward/record.uri?eid=2-s2.0-85117861413&doi=10.1016%2fj.jallcom.2021.162352&partnerID=40&md5=9f3ffe75b83b804d7e6709b5c3c1ba91https://scholars.lib.ntu.edu.tw/handle/123456789/598775The transformation and superelasticity characteristics of solution-treated Ti50Ni48Fe2 and aged-hardened Ti49.2Ni49.3Fe1.5 shape memory alloys during cyclic compressive deformation were investigated. The Ti50Ni48Fe2 alloy could not be precipitation hardened, while the Ti49.2Ni49.3Fe1.5 alloy, aged at 400 °C, was hardened by Ti3Ni4 precipitates. During the cyclic deformation, the B2?R?B19′ transformation peaks broadened and spread to a large temperature span. At the same time, the superelasticity behavior became linear, and the associated elastocaloric cooling capacity decreased to a stable value. Among these samples, Ti49.2Ni49.3Fe1.5 alloy aged at 400 °C for 150 h exhibited the largest recoverable strain in superelasticity and retained the largest cooling effect after 1000 deformation cycles. Furthermore, it showed elastocaloric cooling of ?4.1 °C to ?7.0 °C at operating temperatures of ?40–80 °C. Experimental results revealed that B19′ transformation was suppressed significantly by cyclic deformation, and thus the transformation occurred in a wide temperature range of ?160 to ?50 °C. Additionally, the linear superelasticity exhibited a low slope of the Clausius–Clapeyron relation of about 0.5 MPa/°C. These features allow the alloys to exhibit superelasticiy and the elastocaloric effect over a wider temperature range. ? 2021 Elsevier B.V.ElastocaloricMartensitic transformationPrecipitationShape memory alloysSuperelasticityBinary alloysCoolingDeformationElasticityHardeningIron alloysPrecipitation (chemical)Shape-memory alloyTernary alloysTitanium alloysA-stableCompressive deformationsCooling CapacityCooling effectsCyclic deformationsRecoverable strainTemperature spanWide temperature rangesMartensitic transformationsjournal article10.1016/j.jallcom.2021.1623522-s2.0-85117861413