烧结Nd-Fe-B合金断裂机制和增韧方法

Nd-Fe-B合金磁性能的提升扩大了其应用范围,但也存在韧性差、脆性大、抗震和抗冲击能力差的缺点,使其在机械加工过程中易开裂,降低了成品率和加工精度,提高了生产成本,也限制了其在高精度仪器仪表、高速电机等领域的应用。因而如何提高其力学性能逐渐成为研究的重点,由此需要探索清楚其断裂机制,并采用适当而有效的方法进行该合金的增韧。基于此目的,综述了近年来Nd-Fe-B合金断裂机制方面的研究成果,分析了其主要是沿晶断裂,只是缺陷的存在会增加穿晶断裂的几率。同时,指出了元素的添加和改善制备工艺是合金增韧的两条途径,不过目前并没有从根本上改变其力学性能差的缺点,所以需要在未来的研究中进一步深入,寻求更为行之有效的增韧方式。

Fracture Mechanisms and Toughening Techniques of Sintered Nd-Fe-B Alloys

The magnetic properties of sintered Nd-Fe-B alloy are excellent which enlarges its application scope. However,it has several defects,imcluding low toughness,high brittleness,poor shakeproof and shock resistance, which restrict its application in the high accuracy instrument and high velocity electrical machine.Therefore,resear-ches on its fracture mechanisms and toughening techniques is important.The latest research achievements on fracture mechanism of Nd-Fe-B alloy are summarized.The primary fracture mechanism in the alloy is the intergranular frac-ture,but defects can increase the probability of transgranular fracture.On the other hand,toughness of the alloy might be enhanced by element addition and process improvement.However,these methods did not improve the me-chanical properties fundamentally.As a result,further researches should be conducted in order to find more effective toughening methods.