Microstructure Evolution of Ti-47Al-2Cr-2Nb Alloy in the Liquid-Metal-Cooling (LMC) Directional-Soli

• 作 者: 肖志霞 张虎
• 机 构: School of Materials Science and Engineering,Beijing University of Aeronautics and Astronautics(BUAA)
• 出 处: Journal of Wuhan University of Technology(Materials Science
• 发表日期: 2011年02期
• 关键词: lamellar dendrite withdrawal directional solidified columnar apparatus grains so

The microstructure evolution of Ti-47Al-2Cr-2Nb alloy was investigated on liquid metal cooling type directional solidified apparatus at high temperature gradient.The analysis shows that it is solidified with primary β cells/dendrites,and then α phase is formed through peritectic reaction.Once the columnar grains grow into the steady state,the lamellar orientation inclined with the angle of 45° to the withdrawal direction is more favored than that with parallel to the withdrawal direction.In addition,α phase grain nucleates from β-interdendrite regions,and grows up to the dendritic trunk.If no other α grain hinders its growth,it would occupy the whole dendrite,or it would stop at the dendritic trunk for the weakened motivating drive in the β dendritic core.

The microstructure evolution of Ti-47Al-2Cr-2Nb alloy was investigated on liquid metal cooling type directional solidified apparatus at high temperature gradient. The analysis shows that it is solidified with primary β cells / dendrites, and then α phase is formed through peritectic reaction .Once the columnar grains grow into the steady state, the lamellar orientation inclined with the angle of 45 ° to the withdrawal direction is more favored than that with parallel to the withdrawal direction. In addition, α phase grain nucleates from β-interdendrite regions, and grows up to the dendritic trunk.If no other α grain hinders its growth, it would occupy the whole dendrite, or it would stop at the dendritic trunk for the weakened motivating drive in the β dendritic core.