Mo(Si_(1-x)Al_x)_2/Al_2O_3复合材料的制备与强韧化  

Preparation, Structure and Mechanical Properties of Mo(Si_(1-x)Al_x)_2/Al_2O_3 Composites

作　　者：郭瑞霞[1] 朱高明[1] 王晓虹[1] 牛继南[1] 刘章生[1] 冯培忠[1] 

机构地区：[1]中国矿业大学,江苏徐州221116

出　　处：《稀有金属材料与工程》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)

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.

关 键 词：燃烧合成 二硅化钼 复合材料 合金化 力学性能 

分 类 号：TB33[一般工业技术—材料科学与工程]