Mo_2FeB_2基金属陶瓷烧结过程中显微组织和力学性能的变化

Evolution of Microstructure and Mechanical Properties during the Sintering of Mo_2FeB_2-based Cermets

采用真空烧结法制备了Mo2FeB2基金属陶瓷。运用XRD、SEM、EDS研究了Mo2FeB2基金属陶瓷的烧结过程中显微组织的变化并测试了不同烧结温度下所得金属陶瓷材料的力学性能。实验结果表明:进入L1液相(奥氏体+Fe2B)烧结阶段后,金属陶瓷由于颗粒重排致密度大幅度提高,但溶解-析出过程进行得较缓慢,晶粒基本没有长大。提高烧结温度至L2液相(奥氏体+L1+Mo2FeB2)生成后,由于溶解-析出过程明显加剧,晶粒长大趋势明显,但致密化程度进一步提高。当烧结温度达到1280℃,保温时间为40min时,烧结体接近完全致密,所得材料组织均匀具有较佳力学性能。

Mo2FeB2-based cermets were prepared by vacuum sintering. The microstructure evolution during the sintering of Mo2FeB2-based cermets was studied by XRD, SEM and EDS. The mechanical properties of the cermets sintered at different temperatures were also tested. The results show that the considerable densification resulted from the rearrangement of ceramic particles during L1 liquid phase （austenite＋Fe2B） sintering. However, the grains hardly grew up because the process of dissolution and precipitation was very slow at this stage. When the sintering temperature was increased to which L2 liquid phase （austenite＋L1 ＋ Mo2FeB2） formed, the grains grew up rapidly due to the faster process of solution-precipitation. When being sintered at 1280℃for 40 minutes, the cermets achieved nearly complete densification and had superior mechanical properties and homogeneous microstructure.