原位合成TiC/Al基复合材料研究

Study of thermal stability on in-situ synthesized TiC/Al composites

用LEYBOLD HERAEUS水冷铜坩埚真空电弧炉原位合成制备了TiC/Al基复合材料.X射线衍射谱表明,按20%TiC Al配比,制得TiC Al基复合材料中,TiC是唯一的增强相:在高温显微镜中在400℃、100MPa、真空度为0 00013Pa,压缩5h条件下,材料表现出良好的高温持久强度,TiC相未发生偏聚、差热分析(DTA),显示该材料在900℃以下TiC无相变发生.进一步证明原位TiC/Al复合材料具有良好的热稳定性.光学金相、SEM和TEM观察显示,TiC颗粒与基体界面干净,压缩后位错呈半环状,绕TiC相堆积,说明即使在400℃高温下,加载后位错只能以Orowan机制绕过TiC相.

In this paper, a new process for the synthesis of insitu TiC/Al composites has been developed in LEYBOLDHERAEUS vacuum electrometal furnace equipped with watercooling copper crucible. Xray diffraction (XRD) analysis shows that TiC is the only reinforced phase in 20?%TiC/Al composites. In high temperature microscope, 100 MPa and the pressure of 000013 Pa, the samples show favorable high temperature and endure strength when it is compressed for 5 hours and at 400?℃. TiC phase is not deflected, separated out and grows up. Transmission electron microscope (TEM) phase demonstrates the dislocation morphologies in foreandaft deformations. Differential thermal analysis (DTA) illustrates that no phase transformation occurs in the composites until 900?℃, which proves that insitu TiC composites presents the favorable thermal stability. The clear interfaces between TiC particles are proved by means of the observation in the microscope, scanning electron microscope (SEM) and TEM. The loops of dislocations are piled around TiC phase after compressive deformation at 400?℃, which illuminates that dislocations can only round TiC phase by the Orowan mechanism.