采用整体加热燃烧合成法（即热爆合成）制备了ＴｉＣ－Ａｌ复合体系，利用差热分析（ＤＴＡ）、Ｘ射线衍射分析（ＸＲＤ）和扫描电镜（ＳＥＭ）等手段研究了Ｔｉ－Ｃ－Ａｌ体系中升温速度及Ａｌ含量对ＴｉＣ反应合成过程的影响，分析了Ａｌ基体对ＴｉＣ粒子的形成机理．结果表明，在ＴｉＣ反应合成过程中，首先是Ｔｉ与Ａｌ反应形成Ｔｉ与Ａｌ的化合物，放出热量，随后促使Ｔｉ与Ｃ的放热反应发生，合成ＴｉＣ时放热产生的高温使Ｔｉ与Ａｌ的化合物分解，从而制得ＴｉＣ－Ａｌ复合体系；升温速度及Ａｌ含量只有超过一定值时，该体系才能在较低温度发生热爆反应；当Ａｌ的质量分数从１０％升至５０％时，ＴｉＣ的粒度从５．０μｍ阵至０．５μｍ．
TiC-Al composites were prepared from powders of Ti,C and Al by means of thermal explosion technique.The effects of heating rate and aluminium content on the thermal explosion process,phase composition and microstructure of the reaction products have been studied.By differential thermal analysis,X-ray diffraction and scanning electron microscopy,it is shown that the explosive reaction in the Ti-C-Al system proceeds in such a way that aluminium initially reacts with titanium to form Ti-Al compounds with heat evolution,and then the reaction between titanium and carbon,and the decomposition of Ti-Al compounds to titanium and aluminium are subsequently followed.The certain heating rate and aluminium content are needed if the thermal explosion occurs at low temperature in Ti-C-Al system.As mass fration of aluminium was increased over the range of 10% to 50%,the grain size of TiC decreased approximately from 5.0μm to 0.5μm.
参考文献
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| [4] | HoltJB,MunirZA,JMaterSci,1986 |
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