铜含量对燃烧合成TiB_2-Cu基金属陶瓷组织和性能的影响  

Effect of copper content on the microstructures and properties of TiB_2 based cermets by SHS

作　　者：徐强[1] 张幸红[2] 韩杰才[2] 赫晓东[2] 

机构地区：[1]清华大学材料科学与工程系,北京100084 [2]哈尔滨工业大学复合材料研究所,黑龙江哈尔滨150001

出　　处：《材料科学与工艺》2005年第1期16-20,共5页Materials Science and Technology

基　　金：教育部博士点基金(20020213037)航天创新基金(2002-2004年度).

摘　　要：利用自蔓延高温燃烧合成结合准热等静压技术制备了不同Cu含量的TiB2-Cu基金属陶瓷.为了得到金属粘结剂的最佳含量,研究了Cu含量对TiB2-Cu基金属陶瓷热力学、微观组织和性能的影响.在Ti-B-Cu体系的燃烧合成过程中,可能存在TiB2、TiB和TiCu三个相.热力学计算结果表明TiB2是最稳定的相.随着Cu含量的增加,TiB2-Cu基金属陶瓷的绝热温度(Tad)和燃烧温度(Tc)逐渐降低.燃烧温度会影响产物中陶瓷相的形貌,TiB2颗粒的尺寸随金属含量的增加而减小.TiB2-Cu基金属陶瓷的硬度(HRA)和弯曲强度随着Cu含量的增多均呈现先增加后降低的趋势,最大值分别对应20wt.%和40wt.%的Cu含量.随Cu含量的增加,TiB2-Cu基金属陶瓷的孔隙率由于金属Cu良好的流动性而呈下降趋势,断裂韧性则呈逐渐上升的趋势.材料的韧化机制为裂纹尖端塑性钝化机制和裂纹偏转机制.TiB2-Cu基金属陶瓷的最佳金属粘结剂含量位于40wt.%-50wt.%.TiB2 based cermets with different copper content were produced from titanium powder, boron powder and copper powder by Self-propagating High-temperature Synthesis under conditions of Pseudo Hot Isostat-ic Pressing (SHS/PHIP). In order to obtain the optimal copper content, the effect of copper content on the thermodynamics, microstructures and properties of TiB2 based cermets was investigated. The calculated result of thermodynamics showed that TiB2 was the most stable phase among TiB2, TiB and TiCu in the Ti - B - Cu system. The adiabatic temperatures ( Tad ) and combustion temperatures ( Tc) of TiB2 based cermets decreased with the copper content increasing. Combustion temperature influences the morphology of ceramic in the products. The size of the TiB2 particles in the products decreased with increasing amounts of copper. The hardness (HRA) and bend strength increased firstly, then decreased with copper increasing. Their maximum values appeared at 20 wt. % and 40 wt. % copper, respectively. The porosity of TiB2 based cermets decreased with the copper content increasing due to good fluidity of copper. With the addition of copper, the fracture toughness of TiB2 based cermets increased gradually. Crack-tip plastic blunting by a ductile metallic phase and crack deflection are the principal mechanisms of toughness improvement of TiB2 based cermets. The range of optimal copper content in the TiB2 based cermets is between 40 wt. % and 50 wt. %.

关 键 词：金属陶瓷 TIB2颗粒 组织和性能 自蔓延高温燃烧合成 微观组织 热力学计算 粘结剂 热等静压技术 绝热温度 弯曲强度 

分 类 号：TB333[一般工业技术—材料科学与工程] TB331