块体非晶合金的低温性能研究进展

Research Progress on Cryogenic Temperature Properties of Bulk Amorphous Alloys

非晶合金的结构与性能在极端条件下会发生大的改变,且其变形机理目前尚不统一。为了明确低温极端条件对块体非晶合金力学性能的影响机制,本文综述了块体非晶合金在低温条件下微观形貌、力学性能的变化。主要阐述了低温对其拉伸与压缩力学性能的影响,列举了块体非晶合金在低温下具有高屈服强度等优异的力学性能,如低温下块体非晶合金的屈服强度可达2217 MPa。此外,还评述了块体非晶合金在不同低温条件下电性能和磁性能的变化,发现块体非晶合金在磁制冷方面也有突出的表现,比如Co_(45)Er_(55)和Co_(35)Er_(65)两种块体非晶合金从铁磁到顺磁的转变温度分别为26 K和15 K。根据热力学麦克斯韦关系可确定块体非晶合金的磁熵变值,当Er元素浓度增加时,磁熵变值会减小。在5 T的磁场下,Co_(45)Er_(55)和Co_(35)Er_(65)的磁熵变峰值分别约为10.8 J·kg^(-1)·K^(-1)和9.8 J·kg^(-1)·K^(-1),这说明Co_(35)Er_(65)合金更有望成为磁制冷的候选材料。本文对进一步理解块体非晶合金低温下微观形貌与力学性能的关联具有重要意义,为块体非晶合金在极端低温条件下的应用提供了理论基础,对推动块体非晶合金这一新型材料的工程化应用有重要的理论和实际意义。

The structure and properties of amorphous alloys undergo significant changes under extreme conditions,and the deformation mechanism is not uniform.This paper reviews the changes in the microscopic morphology and mechanical properties of bulk amorphous alloys at extreme cryogenic conditions to clarify the thermal effects on the mechanical properties of amorphous alloys.It mainly elaborates the influence of cryogenic temperature on tensile and compressive mechanical properties for bulk amorphous alloys and lists the excellent mechanical properties of bulk amorphous alloys at cryogenic temperatures,such as a high yield strength of 2217 MPa.In addition,the electrical and magnetic properties of bulk amorphous alloys under different cryogenic temperature conditions are also reviewed,and it is found that bulk amorphous alloys also have outstanding performance in magnetic refrigeration.For example,the transition temperatures from ferromagnetic to paramagnetic for Co_(45)Er_(55) and Co_(35)Er_(65) are 26 K and 15 K,respectively.The change in magnetic entropy is determined according to the thermodynamic Maxwell relationship.With an increase in Er concentration,the magnetic entropy change value also decreases.Under a magnetic field of 5 T,the magnetic entropy change peaks of Co_(45)Er_(55) and Co_(35)Er_(65) are about 10.8 J·kg^(-1)·K^(-1) and 9.8 J·kg^(-1)·K^(-1),respectively,indicating that the Co_(35)Er_(65) alloy is more likely to be a candidate for magnetic refrigeration.The discussion in this paper is of great significance in further understanding the relationship between microscopic morphology and mechanical properties of amorphous alloys at cryogenic temperatures,and provides a theoretical basis for the application of bulk amorphous alloys under extreme cryogenic temperature conditions,which shows important theoretical and practical significance for engineering applications of bulk amorphous alloys as new materials as well.