Superelastic behavior of a metamagnetic Ni–Mn–Sn single crystal

Abstract

A single-crystalline specimen with the composition of Ni 49.5 Mn 38.4 Sn 12.2 shows a 4.9% recoverable transformation strain upon compressive loading. The critical compressive stress increases with temperature at the step of 5.6 MPa/K, whereas upon cycling it decreases by 18.1 MPa/cycle. The microstructure of the specimen undergoes considerable refinement upon superplastic training; however, it is only able to sustain a limited number of cycles (B 5). Martensite training, resulting in a single-variant microstructure, has a profound influence on the austenite start transformation temperature (DT = 29 K), resulting partially from the dissipation of the elastic strain energy. The Ni-Mn-Sn system is an interesting candidate for multiferroic applications given its mechano-magnetic properties and a huge value of the martensitic transformation entropy change (* 50 J/kg K).

Grain Size Effect of the γ Phase Precipitation on Martensitic Transformation and Mechanical Properties of Ni–Mn–Sn–Fe Heusler Alloys

“…Their novel functionalities are only of benefit if their mechanical properties are satisfactory. This is the reason why good shape memory effect and superelasticity are only achieved in either single crystals [ 12 , 13 ] or low dimensional textured polycrystals [ 14 , 15 ], in which reasonable strength and ductility can be guaranteed. It is well known that obtaining good shape memory properties is still challenging in bulk polycrystalline Heusler alloys due to the grain boundary brittleness.…”

Toughening of Ni-Mn-Based Polycrystalline Ferromagnetic Shape Memory Alloys

“…Environmental brittleness can be alleviated by reducing grain boundary areas in polycrystalline alloys or avoided by using single-crystal alloys. Czaja et al [ 20 ] reported that single-crystal Ni 49.5 Mn 38.4 Sn 12.2 alloys could give rise to 4.9% recoverable strain, and strain of up to 9.7% could be obtained under applied stress of 600 MPa. Chernenko et al [ 21 ] reported a recoverable strain as high as 12.0% for <001> oriented Ni 49 Mn 28 Ga 23 single crystals.…”

Стабилизация Мартенсита На Нанопреципитатах И Кинетика Взрывообразного Мартенситного Перехода

“…Исследованию кинетики взрывообразных мартенситных переходов в последнее время уделяется повышенное внимание как перспективному функциональному свойству сплавов с ЭПФ, увеличивающему быстродействие связанных с ними различных устройств, быстродействие которых обычно ограничено тепловой инерцией. Взрывообразные мартенситные переходы обнаружены в настоящее время во многих сплавах, таких, как Cu−Al−Ni [1][2][3], Cu−Al−Fe−Mn [6], Ni−Ti−Nb [8,9], Ni−Fe−Ga−Co [3,4,7,[10][11][12], Ni−Mn−Sn−Tb [13]. В результате предпринятых в последнее десятилетие усилий выявлена связь взрывообразных мартенситных переходов в ряде сплавов с аномальным видом кривых их псевдоупругой деформации.…”