摘要
利用Al-Ti-TiO2-Nb2O5系的原位放热反应合成了Al2O3/TiAl基复合材料,观测了复合材料的相组成和微观形貌及力学性能,并探讨了其强化机理。结果表明:Nb2O5的加入获得了双相基体和弥散分布的Al2O3第二相颗粒,随其掺杂量的增大,组织明显均匀并细化。复合材料的硬度呈直线增加,相对密度也增大。当Nb2O5掺杂量为6wt%时,复合材料的抗折强度最佳,高达642MPa。通过异相界面电子结构解释了双相基体的强化原因,同时以内晶颗粒残余应力原理说明了强度随Nb2O5掺杂量的变化规律。
The in situ exothermic reaction of Al-Ti-TiO2-Nb2O5 system was adopted to fabricate Al2 O3 particles reinforcing TiAl-based composites. The phase composition, microstructure and mechanical properties of the composites were analyzed. Strengthening mechanism of the composites was investigated too. The results show that with Nb2O5 added in, a submicron α2/γ, dual phase structure and Al2O3 second phase can be obtained. The fine second particles disperse around the grains. With increasing Nb2O5 content, there present a homogeneous structure and refinement grains. The Vickers hardness exhibits a linear increase and the relative density increases too. The composite with 6wt% content of Nb2O5 exhibits a good bending strength of 642MPa. The strengthening mechanism in twophase TiAl-based composites is discussed with valence electron structures of biphase interface. And intra - granular particle residual stress strengthening is to explain the variation of strength with the content of Nb2O5.
出处
《航空材料学报》
EI
CAS
CSCD
2007年第3期11-16,共6页
Journal of Aeronautical Materials
基金
国家自然科学基金资助项目(50432010
50672056)
关键词
复合材料
原位反应
力学性能
强化机理
composite
in situ reaction
mechanical property
strengthening mechanism
