硼含量对Fe2B-Mo2FeB2基金属陶瓷微观组织与性能的影响

采用真空烧结工艺制备了4种不同硼含量的Fe₂B-Mo₂FeB₂基金属陶瓷,研究了硼含量对金属陶瓷烧结特性、微观组织与力学性能的影响规律。结果表明,所有试样主要由Fe₂B相、Mo₂FeB₂相和Fe₃B相组成;随着硼含量的增加,烧结过程中形成的液相L1含量逐渐减少,金属陶瓷的最佳烧结温度逐渐升高;并且金属陶瓷的硬度和横向断裂强度也都呈增大的趋势,其中硬度和横向断裂强度的最大值分别为88.52 HRA和685.74 MPa;Mo₂FeB₂相与Fe₃B相(或Fe₂B相)的复合组织在断裂过程中延长裂纹扩展路径,并且长棒状的Mo₂FeB₂相从Fe₃B相(或Fe₂B相)中的拔出都有助于金属陶瓷横向断裂强度的提高。

Effect of boron content on microstructure and mechanical properties of Fe2B-Mo2FeB2-based cermets

Fe₂B-Mo₂FeB₂-based cermets with 4 different boron contents were prepared by vacuum sintering process, and the effect of boron content on sintering characteristics, microstructure and mechanical properties of the cermets was investigated. The results show that all the specimens mainly consist of Fe₂B, Mo₂FeB₂ and Fe₃B phases. With the increase of boron content, the content of liquid phase L1 formed during the sintering process gradually decreases, and the optimal sintering temperature of the cermet gradually increases. Moreover, the hardness and transverse rupture strength of the cermets are also increased, and the maximum values of hardness and transverse rupture strength are 88.52 HRA and 685.74 MPa, respectively. The composite microstructure of Mo₂FeB₂ and Fe₃B (or Fe₂B phase) can extend the crack propagation path during the fracture process, and the pulling out of long rod-shaped Mo₂FeB₂ phase from Fe₃B phase (or Fe₂B phase) is beneficial to the improvement of transverse rupture strength of the cermets.