热压烧结Ti_3AlC_2材料的制备、结构与性能研究  

Study on the Fabrication, Microstructure and Properties of Ti_3AlC_2 Sintered by Hot-Pressing

作　　者：梅炳初[1] 徐学文[1] 朱教群[1] 刘俊[1] 

机构地区：[1]武汉理工大学,湖北武汉430070

出　　处：《稀有金属材料与工程》2005年第5期684-687,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50172037);教育部重点科技项目(02052)

摘　　要：采用热压工艺研究了不同工艺制度和原料中不同的Si含量对Ti3AlC2合成的影响。研究表明:在1300℃~1500℃,30MPa压力和Ar气氛中热压摩尔比为n(TiC)?n(Ti)?n(Al)?n(Si)=2?1?1?0.2的混合粉末,可以得到纯度达98%(质量分数)以上的致密块体Ti3AlC2材料;添加的Si均匀分布在基体中,形成固溶体,当添加Si的摩尔比为0.2时,固溶体的化学式为Ti2.76Al0.78Si0.22C2。烧结试样的晶体为层片状结构,1300℃和1400℃时,烧结试样的晶粒尺寸分别为10μm^15μm和20μm^30μm。材料的维氏硬度为3.3GPa^5.0GPa,弹性模量为289GPa,抗压强度为785MPa,抗弯强度为375MPa,断裂韧性为7.0MPa·m1/2;25℃时,电导率为3.1×106S·m-1,热容为125.4J/mol·K,热导率为27.5W/m·K;热膨胀系数为8.8×10-6K-1。The synthesis of Ti3AlC2 was studied by hot pressing with different conditions. Results indicate that the single-phase bulk Ti3AlC2 was fabricated with the mixture powders n(TiC):n(Ti):n(Al):n(Si)=2:1:(1 similar to 1.1):(0.2 similar to 0.1) in molar ratio, which soaked at 1 300 degrees C similar to 1 500 degrees C for 2 hours under a pressure of 30 MPa and in Ar atmosphere. With the soaked temperature of 1 300 degrees C and 1 400 degrees C, the densities are 4.19 g/cm(3) and 4.22 g/cm(3), the purities are 98 wt% and 98.2 wt%, and the crystals are laminate with the dimension of 10 mu m similar to 15 mu m and 20 mu m similar to 30 mu m, respectively. The additive Si was uniformly distributed in the matrix. When the molar ratio of additive Si was 0.2, the compound can be described with the formula, Ti2.76Al0.78Si0.22C2. The Vicker's hardness, Young's modules, compressive strength, flexural strength and fracture toughness are 3.3 GPa similar to 5.0 GPa, 289 GPa, 785 MPa, 375 MPa and 7.0 MPa(.)m(1/2) respectively. The electric conductivity, heat capacity and thermal conductivity are 3.1 x 10(6) S(.)m(-1), 125.4 J/mol(.)K and 27.5 W/m(.)K at 25 degrees C respectively; the thermal expansion coefficient is 8.8 x 10(6) K-1.

关 键 词：TI3ALC2 热压 力学性能 热性能 电性能 

分 类 号：TB383[一般工业技术—材料科学与工程]