Enhanced cyclability of elastocaloric effect in boron-microalloyed Ni-Mn-In magnetic shape memory alloys
Enhanced cyclability of elastocaloric effect in boron-microalloyed Ni-Mn-In magnetic shape memory alloys
复制标题
硼微合金化 Ni-Mn-In 磁性形状记忆合金弹热效应增强的循环性能
DOI：
10.1016/j.actamat.2017.01.025
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发表时间：
2017
期刊：
影响因子：
9.4
通讯作者：
Wang Y. D.
中科院分区：
文献类型：
--
作者：
Yang Z.;Cong D. Y.;Sun X. M.;Nie Z. H.;Wang Y. D.
弹热制冷是一种很有前途的替代传统蒸汽压缩制冷技术的方法，弹热效应的循环性对弹热制冷的实际应用至关重要。Ni-Mn基磁性形状记忆合金具有令人瞩目的多元热效应（包括弹热效应、磁热效应和压热效应），但由于晶界结合力较弱，其本质上是脆性的，导致弹热效应的循环稳定性较差。在这里，我们证明了与硼微合金化是非常有效的提高机械性能和弹性热效应的Ni-Mn-In金属间化合物磁性形状记忆合金的循环稳定性。不含硼的Ni51.5Mn33In15.5合金的弹热效应仅在150次循环后迅速降低;相比之下，掺硼的（Ni51.5Mn33In15.5）99.7B0.3合金的弹热效应保持稳定，超过150次循环几乎没有降低。硼微合金化提高晶界结合力和细化晶粒是提高合金力学性能和弹热效应循环稳定性的主要原因。此外，由于其增强的机械性能，高绝热温度变化高达6.6 K（550 MPa以下），应力引起的熵变为20.0 J kg− 1 K −1在300 MPa下，成功地实现了18的高性能系数，（Ni51.5Mn33In15.5）99.7B0.3合金，其显示刚好在室温附近的工作温度。这些优点使该合金有望用于室温弹热制冷。该研究对设计高性能的固态机械热冷却弹热材料具有指导意义。
Cyclability of elastocaloric effect is of crucial importance for practical applications of elastocaloric refrigeration which is a promising alternative to the conventional cooling technology based on vapor compression. The well-known Ni-Mn-based magnetic shape memory alloys exhibit fascinating multicaloric effects (including elastocaloric, magnetocaloric and barocaloric effects), but they are intrinsically brittle because of weak grain boundary cohesion, which results in poor cyclic stability of elastocaloric effect. Here we demonstrate that microalloying with boron is very effective in enhancing the mechanical properties and cyclic stability of elastocaloric effect in Ni-Mn-In intermetallic magnetic shape memory alloys. The elastocaloric effect of the boron-free Ni51.5Mn33In15.5alloy degrades rapidly after only ∼20 cycles; in contrast, that of the boron-doped (Ni51.5Mn33In15.5)99.7B0.3alloy remains stable with almost no degradation for more than 150 cycles. The enhancement of mechanical properties and cyclic stability of elastocaloric effect is mainly attributed to the increase of gain boundary cohesion and grain refinement resulting from microalloying with boron. Furthermore, by virtue of its enhanced mechanical properties, a high adiabatic temperature change up to 6.6 K (under 550 MPa), a large stress-induced entropy change of 20.0 J kg−1K−1(under 300 MPa) and a high coefficient of performance of 18 were successfully achieved in the boron-doped (Ni51.5Mn33In15.5)99.7B0.3alloy showing a working temperature just around room temperature. These advantages make this alloy promising for room-temperature elastocaloric refrigeration. This study is instructive for designing high-performance elastocaloric materials for solid-state mechanocaloric cooling applications.