摘要
以Mo、Al、Si和Mo O_34种粉末为原料,通过燃烧合成和真空热压烧结工艺原位制备了(Si_(1-x)Al_x)_2/Al_2O_3复合材料,分析了其燃烧模式、产物相结构、微观组织和力学性能。结果表明:添加Al之后坯体的燃烧合成反应更加剧烈,燃烧模式由螺旋模式转入混沌模式。随着合金化Al含量的增加,基体相结构由C11_b型Mo Si_2转变为C40型Mo(Si,Al)_2,并且在所有复合材料中都可以鉴别出Al_2O_3衍射峰,表明通过燃烧合成技术原位制备了Mo(Si_(1-x)Al_x)_2/Al_2O_3复合材料。复合材料的断裂韧性和抗弯强度最高分别达到4.25 MPa·m^(1/2)和346 MPa,比纯Mo Si_2提高了39%和60%。复合材料的强韧化机制主要有Al合金化强韧化、Al_2O_3第二相颗粒弥散强韧化、玻璃相的消除以及断裂方式的转变。
Mo Mo（Si_（1-x）Al_x）_2/Al_2O_3composites were prepared by combustion synthesis and hot-pressing sintering. The combustion characteristics, phase composition, microstructure and mechanical properties of the Mo Mo（Si_（1-x）Al_x）_2/Al_2O_3 composites were investigated. The results show that the combustion synthesis mode, determined by image analysis, is spiral combustion in Mo Si_2 sample; however, it is chaotic combustion in Mo Mo（Si_（1-x）Al_x）_2/Al_2O_3samples. X-ray diffraction analysis confirms that the main phase composition of combustion products are changed from tetragonal Mo Si_2 to hexagonal Mo（Si,Al）_2 with the increasing of aluminum content, and the diffraction peaks of Al_2O_3 can be identified in Mo（Si_（1-x）Al_x）_2/Al_2O_3 samples. Mo（Si_（0.90）,Al_（0.10））_2/10% Al_2O_3 has the maximum fracture toughness of 4.25 MPa·m（1/2）and bending strength of 346 MPa, which are 39% and 60% larger than those of the monolith Mo Si_2, respectively. The toughening and strengthening mechanism can be attributed to solid solution of aluminum alloying, alumina particle reinforcement, the removal of glass phase and intergranular fracture.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第1期150-156,共7页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51104161)
江苏省"青蓝工程"基金(苏教师[2012]39号)
关键词
燃烧合成
二硅化钼
复合材料
合金化
力学性能
combustion synthesis
molybdenum disilicide
composites
alloying
mechanical properties
