合金元素对铝基体中Al-Ti金属间化合物形貌的影响

Effect of Alloy Elements on Microtopography of TiAl_3 Intermetallic in Al Matrix

研究了Cu、Zn、Si及Mg元素对铝基体中TiAl_3金属间化合物形貌的影响。利用光学显微镜、X-射线衍射仪、扫描电镜及能谱分析仪分析了TiAl_3相的生成及微观形貌。结果表明:TiAl_3在纯铝中大部分为块状及短棒状;当Cu、Zn或者Si元素加入后,TiAl_3相分别呈现出笔直的长棒状、具有一定弧度的长条状及带分支的长条状;然而,当加入Mg元素后长条状TiAl_3的表面变得凹凸不平。熔体热对流的加强、晶体结构的改变、原子替换及降低熔体表面张力是TiAl_3相在各种合金元素作用下表现出不同形貌的主要原因。

The effect of alloy elements Cu,Zn,Si,and Mg on the microtopography of TiA1_3 intermetallic in A1 matrix was discussed. The formation and the microtopography of TiA1_3 phase were investigated by optical microscope （OM）, X-ray diffraction （XRD）, scanning electron microscope （SEM） and energy dispersive X-ray detector （EDS）. The results show that many bulk-like and short rod-like TiA1_3 phases exist in A1 matrix; when Cu, Zn or Si elements are added, TiA1_3 phases present long straight rod-like, strip-like with a certain radian, long strip shaped with some branches shapes, respectively, and yet when Mg element is added, the surface of long strip-like TiA1_3 phase becomes rough. The different microtopographies of TiA1_3 under different addition of the elements can be mainly attributed to the improvement of heat convection in the melts, variation of crystal structure, replacement of atoms and reduction of surface tension of melts.