Solid-state refrigeration is considered a promising alternative to traditional vapor compression refrigeration technology. Researchers demonstrated that Ni–Mn–Ti alloys have a remarkable elastocaloric effect. However, the Ni–Mn–Ti alloy can only operate under a uniaxial stress field due to its antiferromagnetic austenite, which narrows its range of refrigeration temperatures. Here, we activated the magnetism of the alloy by replacing some Ni atoms with Co atoms. The Ni–Co–Mn–Ti–B alloy demonstrates a reversible maximum magnetic entropy change(Δ) of 24.9 J kg K and achieves an adiabatic temperature change of 7.8 K under a 7 T magnetic field. Additionally, we demonstrate that adding boron (0.2%) can improve the mechanical properties and cyclic stability in Ni–Mn–Ti alloys. The elastocaloric effect of 21.3 K with high cycle stability (1013 cycles) were successfully achieved in the directionally solidified (NiCoMnTi)B alloy. Furthermore, we have demonstrated that the magnetoelastic coupling effect can effectively extend the refrigeration temperature range. The alloys achieved large caloric effects in the temperature range of 240 K–340 K. This provides a new strategy for designing high-performance materials for wide-temperature-domain refrigeration.

中文翻译：

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Co 和 B 共掺杂 Ni-Mn-Ti 合金在宽制冷温度范围内具有大的可逆多热量效应

固态制冷被认为是传统蒸汽压缩制冷技术的有前途的替代品。研究人员证明 Ni-Mn-Ti 合金具有显着的弹热效应。然而，由于Ni-Mn-Ti合金具有反铁磁性奥氏体，只能在单轴应力场下工作，这缩小了其制冷温度范围。在这里，我们通过用 Co 原子取代一些 Ni 原子来激活合金的磁性。Ni-Co-Mn-Ti-B合金表现出24.9 J kg K的可逆最大磁熵变(Δ)，并在7 T磁场下实现了7.8 K的绝热温度变化。此外，我们证明添加硼 (0.2%) 可以提高 Ni-Mn-Ti 合金的机械性能和循环稳定性。定向凝固(NiCoMnTi)B合金成功实现了21.3 K的弹热效应和高循环稳定性（1013次循环）。此外，我们还证明磁弹性耦合效应可以有效地扩大制冷温度范围。该合金在240 K-340 K的温度范围内实现了大的热效应，这为设计用于宽温域制冷的高性能材料提供了新的策略。