颗粒增强钛基复合材料持久性能研究

目的研究颗粒增强钛基复合材料的持久性能,了解其影响因素。方法以TP-650钛基复合材料(属Ti-Al-Zr-Sn-Mo-Nb系合金)为研究对象,材料经过热处理后,加工成Ф5mm标准的持久实验试样,利用Bn-2持久试验机,在650℃/220MPa、650℃/300MPa、600℃/220MPa、600℃/300MPa条件下进行持久试验,采用Olympus光学显微镜观察钛基复合材料的组织。用Gatan Mode 600B双喷离子减薄机制备TEM试样,在JEOL JEM-200CX透射电镜下进行观察,研究了持久过程中裂纹的形成、位错、TiC颗粒的行为对材料持久性能的影响。结果及结论在持久过程中,复合材料的断裂裂纹萌生及扩展和TiC颗粒密切相关,持久断裂过程是空洞在TiC/Ti界面和晶界上形成、长大、相互合并成晶界裂纹的过程,TiC颗粒以及α、β相中位错可以改变裂纹的扩展方向,从而改善材料的持久性能。

Research On creep rupture properties of particulate-reinforced titanium matrix composites

Objective-To study the creep rupture properties of particulate-reinforced titanium ma- trix eomposites（TMCs） and understand its influencing factors Methods-The research object TP-650 TMCs, an alloy consisting of Ti, Zr, Sn, Mo and Nb, is processed by the heat treatment to make into the standard specimens for tensile creep and rupture test, whose diameter is 5 ram. The creep rupture properties are tested by Bn-2 creep rupture strength testing machine at 650 ℃/220 MPa, 650 ℃/300 MPa, 600 ℃/220 MPa and 600 ℃/300 MPa; the microstructure of TMCs is observed with Olympus Optical Microscope, and then TEM test specimens are prepared with Gatan-600B Dual Ion Mill and observed with JEOL-JEM-200 CX transmission electron microscope to study the effect of crack forma tion, dislocations and the behavior of the TiC particles on the properties of particulate-reinforced TMCs during the persistent process. Results/Conclusion-The fracture crack initiation and extension of TMCs are closely related to TiC particles in fracture process. The creep rupture process under ther mal load is the one in which inanition forms, grows up and mutually merges into crystal boundary crack in the interphase of TiC/Ti or the crystal boundary. The TiC particles and dislocation of α phase and β phase change the propagation direction of the crack, thus improving creep rupture properties.