FeB粒度对Mo_2FeB_2基金属陶瓷硬质相形貌及力学性能的影响  

Effects of FeB Particle Size on Hard Phase Morphology and Mechanical Properties of Mo_2FeB_2-based Cermet

作　　者：夏志强[1] 郑勇[1] 吕学鹏[1] 周伟[1] 赵毅杰[1] 

机构地区：[1]南京航空航天大学材料科学与技术学院,江苏南京210016

出　　处：《硬质合金》2014年第5期290-296,共7页Cemented Carbides

基　　金：国家自然科学基金(51174118);材料成形与模具技术国家重点实验室开放课题研究基金(P2015-02);江苏省"六大高峰人才"(XCL-029)资助项目

摘　　要：以Mo、Fe、Cr、Ni和不同粒度的Fe B粉为原料,采用反应硼化烧结法制备了Mo2Fe B2基金属陶瓷。研究了Fe B粉粒度对金属陶瓷硬质相形貌及力学性能的影响。结果表明:当Fe B粉较粗时,在固相反应阶段生成的Mo2Fe B2硬质相颗粒较粗,并在随后的液相烧结过程中沿c轴优先生长,最终呈粗大的长条状;当Fe B粉较细时,固相反应进行较完全,生成的硬质相颗粒细小,其Mo含量相对较高,晶格常数c与a之间差距缩小,各向异性减小,硬质相沿c轴的生长得到抑制,最终呈细小的近等轴状。当硬质相呈近等轴状时,由于硬质相颗粒平均尺寸较小,金属陶瓷具有较高的抗弯强度和硬度;当硬质相呈长条状时,金属陶瓷具有较好的断裂韧性,其增韧机制主要为裂纹偏转和颗粒桥接。Mo2Fe B2-based cermet was prepared by reaction boronizing sintering process using Mo, Fe, Cr, Ni and different particle size of Fe B powder as raw materials. The effects of the Fe B particle size on the morphology of the cermet hard phase and mechanical properties were studied. The results show that when using coarse Fe B powder, coarse Mo2 Fe B2hard phase grains are formed during solid phase sintering and grow along c axis during subsequent liquid phase sintering,finally coarse elongated morphology is formed. When using finer Fe B powder, the value solid phase reaction is almost completely carried out, the obtained hard phase particles are fine with higher Mo content, the value lattice constant a approaches to that of lattice constant c, the anisotropy of the hard phase is decreased, thereby the grain growth of the hard phase is inhibited, finally the morphology of the hard phase changes to nearly quasi-equiaxed shape and the particles are fine. The Mo2 Fe B2-based cermet with quasi-equiaxed hard phase grains has relatively high transverse rupture strength and hardness due to the small average size of Mo2 Fe B2particle. The Mo2 Fe B2-based cermet with elongated hard phase grains has relatively high fracture toughness due to the crack deflection and particle bridging.

关 键 词：MO2FEB2基金属陶瓷 硬质相 形貌 力学性能 

分 类 号：TG148[一般工业技术—材料科学与工程]