(上海交通大學(xué) 金屬基復(fù)合材料國家重點(diǎn)實(shí)驗(yàn)室，上海 200030)
摘 要: 利用鈦與石墨之間的自蔓燃高溫合成反應(yīng)經(jīng)普通的鈦合金鑄造工藝制備了TiC增強(qiáng)的鈦基復(fù)合材料。借助X射線衍射儀、光學(xué)金相顯微鏡和透射電鏡分析了鈦基復(fù)合材料的物相組成和增強(qiáng)體的微觀結(jié)構(gòu)。結(jié)果表明：復(fù)合材料由TiC增強(qiáng)體和基體鈦合金組成。TiC顯示 兩種不同的形態(tài)：樹枝晶狀和等軸或近似等軸狀。原位合成的增強(qiáng)體TiC以溶解-析出的方式生長。從二元相圖分析，凝固過程經(jīng)歷三個階段： 初晶TiC，二元共晶β-Ti+TiC和固態(tài)相變。由于成分過冷的形成，初晶TiC以樹枝晶的形態(tài)生長。二元共晶TiC以等軸或近似等軸狀生長。少量的TiC在形核與長大的過程中形成孿晶結(jié)構(gòu)，孿晶面是(111)面。
關(guān)鍵字: 鑄造；鈦基復(fù)合材料；微觀結(jié)構(gòu)；TiC
TiC in in situ synthesized titanium
matrix composites
ZHANG Xiao-nong, WU Ren-jie
（State Key Laboratory of Metal Matrix Composites,
Shanghai Jiaotong University, Shanghai 200030, China）
Abstract:TiC reinforced titanium matrix composites were produced by non-consumable arc-melting technology utilizing the selfpropagation high-temperature synthesis (SHS) reaction between titanium and graphite. X-ray diffraction (XRD) was used to identify the phases in the composites. Microstructures of the composite s were observed with optical microscope (OM) and transmission electron microscope (TEM). The results show that there are two phases in the composites: TiC and titanium matrix alloy. TiC shows two different shapes: dendritic shape, equiaxed or near-equiaxed shape. The in situ synthesized TiC grows in a way of dissolution-precipitation. Analysis of binary phase diagram determined that the solidification path undertook the following three stages: primary TiC, binary eutectic β-Ti+TiC and solid transformation. Primary TiC grows in dendritic shape due to the formation of composition undercooling. Binary eutectic TiC grows in equiaxed or near-equiaxed shape. A small quantity of TiC may form twin structure during nucleation and growth. The twin plane is (111) plane.
Key words: casting; titanium matrix composites; microstructure; TiC
