新型Ti_3AlC_2-Al_2O_3/TiAl_3复合材料的组织结构与性能  

Microstructure and properties of new type Ti_3AlC_2-Al_2O_3/TiAl_3 composites

作　　者：李晓梅[1] 肖华强[2] 曾勇[1] 陈维平[1] 

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640 [2]贵州大学机械工程学院,贵阳550025

出　　处：《复合材料学报》2015年第1期108-116,共9页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(51271080);广东省自然科学基金(S2011010002227);高等学校博士学科点专项科研基金(201001721100033)

摘　　要：利用Al-TiO2-TiC体系,通过机械球磨和反应热压制备出Ti3AlC2与Al2O3两相原位内生成增强TiAl3金属基复合材料。借助DSC、XRD、SEM和TEM研究了复合材料的反应机制、显微组织、力学性能及抗氧化性能。结果表明,球磨50h后的复合粉末经1 250℃/50 MPa保温10min烧结后可得到组织均匀细小且致密的Ti3AlC2-Al2O3/TiAl3复合材料,其密度、维氏硬度、室温三点弯曲强度、断裂韧性及压缩强度分别为3.8g/cm3、8.4GPa、658.9 MPa、7.9 MPa·m1/2和1 742.0 MPa,1 000℃的高温压缩强度为604.1 MPa。Ti3AlC2-Al2O3/TiAl3复合材料的增韧机制主要包括Ti3AlC2和Al2O3颗粒的剥离、Ti3AlC2相导致的裂纹偏转和桥接以及Ti3AlC2颗粒的变形及层裂。Ti3AlC2-Al2O3/TiAl3复合材料在700~1 000℃温度区间内生成的氧化层虽不致密,但仍表现出优异的抗高温循环氧化性能。The TiAl3 matrix intermetallic composites reinforced by in-situ synthesized two phases of Ti3AlC2 and Al2O3 were produced by mechanically ball-milled and hot pressing of Al-TiO2-TiC system.The reaction mechanism,microstructure,mechanical properties and oxidation-resistance properties of the composites were investigated using DSC,XRD,SEM and TEM.The results indicate that dense Ti3AlC2-Al2O3/TiAl3 composites with homogeneous and pyknotic microstructure can be obtained by sintering 50hball-milled power mixture at 1 250 ℃/50 MPa for10 min.The density,Vickers hardness,three-point bending strength,fracture toughness and compressive strength at room temperature of Ti3AlC2-Al2O3/TiAl3 composites reach 3.8g/cm3,8.4GPa,658.9 MPa,7.9 MPa·m1/2and 1 742.0MPa,respectively,and the elevated-temperature compressive strength at 1 000℃reaches 604.1MPa.The toughening mechanism of Ti3AlC2-Al2O3/TiAl3 composites is primarily attributed to the pull-out of Ti3AlC2 and Al2O3particles,crack deflection and crack bridging by Ti3AlC2 phase,and the deformation and delamination of Ti3AlC2 particles.Tough the oxidation scales generated in the temperature range from 700 to 1 000 ℃ are not dense,the Ti3AlC2-Al2O3/TiAl3 composites still exhibit excellent cyclic oxidation resistance.

关 键 词：复合材料 组织结构 TIAL3 反应热压 原位合成 力学性能 抗氧化性能 

分 类 号：TB33[一般工业技术—材料科学与工程]