Ni-Fe-Ga foam with hierarchical pore architecture was created by replication casting. The annealed foam had an open porosity 53% and reversible superelasticity with recoverable strain 4.9%. An adiabatic temperature change of 4.1 K with low hysteresis and coefficient of performance 22 were obtained under an external stress 70 MPa. The foam showed improved cyclic stability ($\sim 2.8\mathrm{K}$ in 194 cycles) because of low hysteresis loss under small stress and high crack initiation/propagation resistance in small size nodes and struts, which demonstrated a feasible strategy to enhance the mechanical and functional stabilities of ferromagnetic shape memory alloys via tailoring the material architectures. Nevertheless, the achieved elastocaloric cooling stability still cannot satisfy (${10}^7$ cycles) the commercial application, therefore, it should be further explored to become a promising candidate for elastocaloric material.

中文翻译：

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具有分层孔隙结构的多晶Ni-Fe-Ga泡沫的弹性热效应

通过复制铸造创建了具有分层孔结构的Ni-Fe-Ga泡沫。退火泡沫的开孔率为53％，可逆超弹性为4.9％，可恢复应变。在70 MPa的外部应力下获得了4.1 K的绝热温度变化，具有低磁滞和性能系数22。泡沫显示出改善的循环稳定性（$〜2.8\mathrm{ķ}$在194个周期中），是由于在小应力下低磁滞损耗以及在小尺寸节点和支柱中具有较高的抗开裂/蔓延能力，这表明通过调整材料结构来增强铁磁形状记忆合金的机械和功能稳定性的可行策略。然而，所获得的弹性热冷却稳定性仍不能满足（${10}^7$ 周期）商业应用，因此，应进一步探索成为弹性材料的有前途的候选人。