Effects of heat treatment on dual phase structure carbides in Ti-34Al matrix composite
来源期刊：中国有色金属学报(英文版)2003年第z1期
论文作者：WANG Hong-wei(王宏伟) FANG Wen-bin(房文斌) WEI Zun-jie(魏尊杰) ZENG Song-yan(曾松岩)
文章页码：128 - 132
Key words：composite; dual phase structure; TiC; Ti3AlC
Abstract: Ti-34Al matrix composite fabricated by melt-casting process was annealed at different temperatures. The constitution and morphology of carbides in composite were investigated using X-ray diffraction, scanning electron microscopy and electron probe microscope analysis. The results reveal that the as cast Ti-34Al composite is composed of Ti3Al, TiAl, TiC and Ti3AlC in which carbides distributing at grain boundaries are TiC+Ti3AlC dual phase structure. The core particle is TiC and the interfacial transition zone is Ti3AlC existing between TiC particle and α+γ matrix. Ti3AlC is in equilibrium with α2-Ti3Al and γ-TiAl when the alloy was annealed at 900℃, while Ti3AlC reaches equilibrium with α-Ti and γ-TiAl at 1250℃. In α2+γ phase field, TiC+Ti3AlC dual phase structure particles in as cast alloy change into thin elongated plate Ti3AlC. When the composite was annealed in α+γ phase field, the dual phase structure particles change into single phase blocky and lath-like Ti3AlC particles, and TiC in dual phase structure particles dissolved leading Ti to precipitate within Ti3AlC particles. The volume fraction of Ti precipitates within the blocky particles is much higher than within lath-like particles.
WANG Hong-wei(王宏伟)1, FANG Wen-bin(房文斌)2, WEI Zun-jie(魏尊杰)1, ZENG Song-yan(曾松岩)1
(1. School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China;
2.School of Materials Science and Engineering,
Weihai Branch of Harbin Institute of Technology, Weihai 264209, China)
Abstract:Ti-34Al matrix composite fabricated by melt-casting process was annealed at different temperatures. The constitution and morphology of carbides in composite were investigated using X-ray diffraction, scanning electron microscopy and electron probe microscope analysis. The results reveal that the as cast Ti-34Al composite is composed of Ti3Al, TiAl, TiC and Ti3AlC in which carbides distributing at grain boundaries are TiC+Ti3AlC dual phase structure. The core particle is TiC and the interfacial transition zone is Ti3AlC existing between TiC particle and α+γ matrix. Ti3AlC is in equilibrium with α2-Ti3Al and γ-TiAl when the alloy was annealed at 900℃, while Ti3AlC reaches equilibrium with α-Ti and γ-TiAl at 1250℃. In α2+γ phase field, TiC+Ti3AlC dual phase structure particles in as cast alloy change into thin elongated plate Ti3AlC. When the composite was annealed in α+γ phase field, the dual phase structure particles change into single phase blocky and lath-like Ti3AlC particles, and TiC in dual phase structure particles dissolved leading Ti to precipitate within Ti3AlC particles. The volume fraction of Ti precipitates within the blocky particles is much higher than within lath-like particles.
Key words:composite; dual phase structure; TiC; Ti3AlC
