顯微組織演變
( 1. 西安交通大學(xué) 金屬材料強(qiáng)度國(guó)家重點(diǎn)實(shí)驗(yàn)室，
西安 710049；
2. 西安建筑科技大學(xué) 材料科學(xué)與工程學(xué)院， 西安 710055)
摘 要: 在研究Ti， C， A1摩爾比為2∶1∶1的混合粉末自蔓延高溫合成Ti↓2AlC過(guò)程中的組織演變中，將在試樣中蔓延的燃燒波強(qiáng)制淬熄。 用掃描電鏡觀察了淬熄試樣中的顯微組織演變， 測(cè)定了其燃燒溫度， 并用X射線衍射檢測(cè)了燃燒合成產(chǎn)物的相組成。 結(jié)果表明： 合成反應(yīng)以Al的熔化為先導(dǎo)； 反應(yīng)過(guò)程可用溶解—析出—熔化—結(jié)晶機(jī)制描述；該反應(yīng)具有不完全性， 可能是由于實(shí)驗(yàn)中使用了較粗的鈦粉和鋁粉所致。
關(guān)鍵字: Ti2AlC；可加工陶瓷； 自蔓延高溫合成； 組織演變
temperature synthesis of Ti2AlC machinable ceramics
（ 1. State Key Laboratory for Mechanical Behavior of Materials，Xi′an Jiaotong University，
Xi′an 710049， China；
2. School of Materials Science and Engineering，
Xi′an University of Architecture and Technology， Xi′an 710055， China）
Abstract: In the study of microstructural evolution during self-propagating high-temperature synthesis of Ti2AlC machinable ceramics from Ti-Al-C powders, a propagating combustion wave in the sample was quenched, and the microstructural evolution was observed with scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The combustion temperature was measured, and the phase constituent of the synthesized product was inspected by X-ray diffraction (XRD). The results show that the combustion reaction is preceded by melting of the Al particle, and it proceeds in a dissolving-precipitating-melting-crystallizing mechanism. In addition, the reaction is incomplete, this is because the coarser Ti and Al powders are used in the experiment.
Key words: Ti2AlC； machinable ceramics； self-propagating high-temperature synthesis； microstructural evolution
