热处理对原位烧结合成Mo_2FeB_2陶瓷组织与性能的影响

用X射线衍射仪、扫描电镜、万能材料试验机研究了真空液相烧结制备的Mo2FeB2金属陶瓷热处理后的组织与性能。结果表明,真空液相烧结Mo2FeB2金属陶瓷主要由Mo2FeB2、MoB2、Fe2B相和铁基粘结相组成,经700～1000℃热处理后,MoB2、Fe2B相逐渐转化为Mo2FeB2相,并且Mo2FeB2晶粒细化,呈规则块状均匀分布在铁基粘结相中。Mo2FeB2金属陶瓷在700～1000℃范围内随热处理温度的升高,弯曲强度、断裂韧性与维氏硬度均增加,当热处理温度为1000℃时,其值分别达到1182.42MPa、13.59MPa·m1/2、9.114GPa,与未处理试样相比,分别增加了5.4%、6.0%、7.0%。

Effects of heat treatment on microstructure and properties of Mo2FeB2 cermet synthesized by in situ liquid phase sintering

Microstructure and properties of Mo2FeB2 cermet after heat treatment were investigated by means of X-ray diffraction(XRD),scanning electron microscopy(SEM)and bending,fracture toughness and hardness tests.The results show that the microstructure of Mo2FeB2 cermet consists of Mo2FeB2,MoB2,Fe2B and iron based binding phases.After heat treatment at 700-1000 ℃,MoB2 and Fe2B are transformed into the phase of Mo2FeB2,and the grains of Mo,FeB2 are refined ant it is homogeneously distributed in the iron based binding phase with regular block-shape.The bending strength,fracture toughness and vickers hardness of the cermet increase with increasing heat treatment temperature in the range of 700-1000℃,and the values of those reach 1182.42 MPa,13.59 MPa·m1/2 and 9.114 GPa,respectively,and increase by 5.4%,6.0% and 7.0% as compared with that of un-treated specimens for Mo2FeO2 cermet heat-treated at 1 000℃.