放电等离子烧结NdFeB永磁材料的强韧化

Mechanical properties of spark plasma sintering NdFeB permanent magnets

  • 摘要: 分别采用放电等离子烧结技术(Spark Plasma Sintering,简称SPS技术)和传统烧结技术制备了成分为Nd12.2Pr2Dy2FebalAl1Nb0.3Cu0.2B6的烧结NdFeB永磁体。研究了所制备磁体的冲击韧性和抗弯强度,并利用扫描电镜(SEM)观察了磁体的显微组织形貌。结果表明:SPS技术制备的Nd-FeB永磁体的冲击韧性和抗弯强度较传统烧结磁体有显著提高,前者的冲击韧性与抗弯强度分别为Kc=0.955J/m2、σbb=402.25 MPa,后者仅为Kc=0.709J/m2、σbb=278.97MPa。显微组织观察发现,SPS NdFeB永磁体的主相晶粒细小均匀、富钕相细小弥散且彼此隔断;断口表现为较明显的解理断裂特征;而传统烧结磁体主相晶粒较粗大、富稀土相粗大且彼此连接,断口呈明显的沿晶断裂特征。

     

    Abstract: Spark Plasma Sintering technique(SPS) and conventional sintering technique had been used to prepare Nd12.2Pr2Dy2FebalAl1Nb0.3Cu0.2B6 sintered permanent magnet.Impact toughness and bending strength of the alloys were investigated;Microstructure and fracture morphology of the alloys were observed by scanning electronic microscopy(SEM).The result indicates that the impact toughness of 0.955J/m2 in SPS NdFeB is better than that of 0.709J/m2 in conventional sintered NdFeB,and the bending strength of 402.25 MPa in SPS NdFeB is also much better than that of 278.97 MPa in conventional sintered magnet.The microstructure of SPS NdFeB alloy is composed of fine and uniform main phase grains as well as fine and even distributed Nd-rich phase.The fracture morphology shows that some cleavage face is observed in SPS NdFeB.However,the microstructure of conventional sintered NdFeB is composed of coarse grains,and its fracture morphology shows a typical intergranular fracture.

     

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