摘要
以Mo、Si混合粉末为原料,采用放电等离子烧结技术原位制备MoSi_2陶瓷。利用X射线衍射仪、扫描电镜、维氏硬度计、电子万能材料试验机等,研究1 300,1 400和1 500℃下烧结的MoSi_2陶瓷物相组成、微观结构及力学性能。结果表明:MoSi_2陶瓷由MoSi_2和少量Mo_5Si_3/Mo_(4.8)Si_3C_(0.6)及SiO_2组成;随烧结温度升高,第二相Mo_5Si_3/Mo_(4.8)Si_3C_(0.6)含量增多,并发生Mo_5Si_3向Mo_(4.8)Si_3C_(0.6)的相转变;第二相Mo_5Si_3/Mo_(4.8)Si_3C_(0.6)含量增多可细化基体组织,材料沿晶断裂的比例增加,具有一定的强韧化作用;1 500℃烧结的MoSi_2陶瓷综合性能最佳,其致密度为99.5%,维氏硬度为9.8 GPa,抗弯强度和断裂韧性分别为313 MPa和2.9 MPa·m^(1/2)。
MoSi2 ceramics were synthesized in one step by in-situ reactive spark plasma sintering using Mo and Si powders as raw materials. The phase composition, microstructure and mechanical properties of MoSi2 sintered at 1300, 1400 and 1 500 ℃ were investigated by X-ray diffraction, scanning electron microscope, Vickers hardness tester and electronic universal material tester, etc. The results show that MoSi2 ceramics are composed of MoSi2 and trace amounts of Mo5Si3/Mo4.8Si3C0.6 and SiO2. With increasing of the sintering temperature, the content of the second phases Mo5Si3/Mo4.8Si3C0.6 increases and there is a phase transition from MosSi3 to Mo4.8SiaC0.6. The structure can be refined with increasing content of the second phases and more intergranular fracture can be found, which results in strengthening and toughening of the ceramic. The sample sintered at 1 500 ℃ possesses the best comprehensive performance： relative density is 99.5%, Vickers hardness is 9.8 GPa, bending strength and fracture toughness are 313 MPa and 2.9 MPa＇mv2, respectively.
出处
《粉末冶金材料科学与工程》
北大核心
2017年第4期563-568,共6页
Materials Science and Engineering of Powder Metallurgy
基金
中国博士后科学基金资助项目(2014M562129)
关键词
MOSI2
放电等离子烧结
原位反应
烧结温度
微观结构
力学性能
MoSi2
spark plasma sintering
in-situ reaction
sintering temperature
microstructure
mechanical property
