摘要
利用Ti-Al-TiO2体系的放热反应,采用热压工艺原位合成了Al2O3/TiAl复合材料。研究了Nb2O5加入量对复合材料结构与力学性能的影响。结果表明,相组成中有γ-TiAl、α2-Ti3Al、Al2O3和NbAl3相。随Nb2O5加入量的增大,复合材料的密度、相对密度和硬度逐渐增大;抗弯强度和断裂韧度在加入量为6%时达到最大,分别为398.5MPa和6.99MPa.m1/2,此后随其含量增大而降低。组织分析表明,随Nb2O5加入量的增加,Al2O3粒子团聚度减弱,沿晶界弥散分布,双相γ+α2片层组织不断细化,结构更加均匀。Nb2O5对力学性能的影响主要表现在调节相含量和细化组织。
In-situ Al2O3/TiAl composites were prepared by hot-pressing method based on the exothermic reaction of Ti-Al-TiO2-Nb2O5 system.Effects of Nb2O5 addition on microstructure and mechanical properties of the prepared composites were investigated by SEM(scanning electron microscope),XRD(X-ray diffraction).The results indicate that the as-sintered composites consist of γ-TiAl,α2-Ti3Al,Al2O3 phase and NbAl3 phase.With increasing in Nb2O5 content,the density,relative density and hardness of the composites are gradually increased,meanwhile,bending strength and fracture toughness are firstly increased and then decreased,in which the maximum values are 398.5 MPa and 6.99 MPa·m1/2,respectively,with 6% Nb2O5 content.Microstructure analysis shows that,sintered at 1200℃,the composites present a γ+α2 lamellar structure.With Nb2O5 content increase,the aggregate degree of Al2O3 particles is improved with dispersively distributed along the grain boundary,meanwhile,the dual-phase γ+α2 lamellar structure is refined with more homogeneous distribution.Nb2O5 additive plays an important role in adjusting phase content and refining structure,which is beneficial to improving the properties of the composites.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2009年第6期549-552,共4页
Special Casting & Nonferrous Alloys
基金
陕西理工学院引入人才科研启动项目(SLGQD0751)
