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采用反应硼化烧结法制备了Mo_2FeB_2基金属陶瓷。使用扫描电镜(SEM),X射线衍射仪(XRD)研究了固相硼化反应阶段800~1 010℃的升温速率对Mo_2FeB_2基金属陶瓷显微组织和力学性能的影响。研究结果表明:从800℃以不同的升温速率(1~9℃/min)升温升至1 010℃时,随着升温速率的升高,粘结相体积分数先增加后减少,硬质相平均晶粒尺寸和长径比逐渐减小,Mo_2FeB_2硬质相晶格常数a逐渐降低,c基本保持不变,硬质相形貌逐渐由长条状转变为近等轴状;随着升温速率的升高,金属陶瓷抗弯强度先升高后降低,硬度逐渐升高,断裂韧性逐渐降低。以5℃/min升温得到的金属陶瓷可获得较为均匀的显微组织,且具有较好的综合力学性能,其抗弯强度为2 367.5 MPa,硬度为88.2 HRA,断裂韧性为27.6 MPa·m~(1/2)。
Mo_2FeB_2 based cermets were prepared by reactive borosilicate sintering. The microstructure and mechanical properties of Mo_2FeB_2 based cermets were investigated by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The effects of heating rate at 800 ~ 1 010 ℃ during solid phase boriding reaction were investigated. The results show that the volume fraction of the binder phase first increases and then decreases with increasing heating rate from 800 ℃ to 1 010 ℃ when the temperature increases from 1 ℃ to 9 ℃ / min, The grain size and the aspect ratio decreased gradually, the lattice constant a of Mo_2FeB_2 decreased gradually, c remained almost unchanged, and the morphology of hard phase gradually changed from long strip to nearly equiaxed strip. With the increase of heating rate The flexural strength of cermets first increased and then decreased, the hardness gradually increased and the fracture toughness decreased gradually. The cermet obtained by heating at 5 ℃ / min can obtain a more uniform microstructure and has better mechanical properties, with a bending strength of 2 367.5 MPa, a hardness of 88.2 HRA and a fracture toughness of 27.6 MPa · m ~ (1/2).