Abstract With large entropy changes and flexible preparation processes, (Mn, Fe)2(P, Si) alloys have attracted wide interest from researchers for magnetic refrigeration. Cu doping can compensate for the mechanical properties, but will increase thermal hysteresis (ΔThys) and decrease the Curie temperature (TC) of (Mn, Fe)2(P, Si) alloys. To tune the TC to room temperature while maintaining low thermal hysteresis and good mechanical properties, Cu-B co-doping is applied to (Mn, Fe)2(P, Si) alloys. The results demonstrated that as the amount of B increases in Mn1.05Fe0.9P0.5-xSi0.5Cu0.10Bx alloys, the TC continuously increases from 261 K to 344 K, and the ΔThys decreases by 76%. Contour plots of XRD patterns show the shifts in Bragg angles near the Curie temperature, which are ascribed to the increase in the lattice parameters during phase transitions, leading to high internal stress. After long-term annealing, Cu tends to segregate at the grain boundaries to act as a buffer between the Fe2P-type main phase. Therefore, stress from lattice deformation during first-order phase transitions can be absorbed. This study presents a new technical route to obtain magnetic refrigeration materials with high magnetocaloric effects and good mechanical properties by co-doping Cu and B, which is instructive for engineering applications.

中文翻译：

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Cu和B共掺杂对Mn1.05Fe0.9P0.5-Si0.5Cu0.10B合金磁热效应、相变和力学性能的影响

摘要 (Mn, Fe)2(P,Si)合金具有熵变大、制备工艺灵活等特点，在磁制冷方面引起了研究人员的广泛兴趣。Cu掺杂可以补偿机械性能，但会增加（Mn，Fe）2（P，Si）合金的热滞后（ΔThys）并降低居里温度（TC）。为了在保持低热滞后和良好机械性能的同时将 TC 调整到室温，将 Cu-B 共掺杂应用于 (Mn, Fe)2(P, Si) 合金。结果表明，随着Mn1.05Fe0.9P0.5-xSi0.5Cu0.10Bx合金中B含量的增加，TC从261 K持续增加到344 K，ΔThys下降了76%。XRD 图案的等高线图显示了居里温度附近布拉格角的变化，这归因于相变期间晶格参数的增加，导致高内应力。长期退火后，Cu倾向于在晶界偏析，作为Fe2P型主相之间的缓冲剂。因此，可以吸收一阶相变期间晶格变形的应力。本研究为通过共掺杂Cu和B获得具有高磁热效应和良好机械性能的磁制冷材料提供了一种新的技术路线，对工程应用具有指导意义。