Lamellar orientations and growth directions of β dendrites in directionally solidified Ti-47Al-2Cr-2Nb alloy

作者：Xiao, Zhixia; Zheng, Lijing; Yan, Jie; Yang, Lili; Zhang, Hu^*

来源：Journal of Crystal Growth, 2011, 324(1): 309-313.

DOI：10.1016/j.jcrysgro.2011.04.021

• Crystal morphology
• Dendrites
• Directional solidification
• Optical microscopy
• Bridgman technique
• Alloys

Lamellar orientations and growth directions of beta dendrites are investigated in Ti-47Al-2Cr-2Nb alloy with different temperature gradients (G) and growth rates (v) by directional solidification technique. It shows that p phase is the primary solidification phase when G/v ratio is equal to or less than 4.8 x 10(8) Ks m(-2), while the lamellar orientations vary with G and nu. At G of 40 K/cm and nu of 1 mm/min, lamellar orientation inclined at the angle of 74 to growth direction is preferred. As G is increased to 125 K/cm, or nu is increased to 10 mm/min, lamellar orientation aligned at about 45 to growth direction is favored. At intermediate G and nu, the orientations are aligned in the range of 45-78 degrees to growth direction. Calculation of beta-dendrite growth direction shows that growth direction is < 2 2 1 > (beta) at low G or nu, while the direction tends to be < 1 0 0 > (beta) at high G or nu.

• 出版日期2011-6-1
• 单位北京航空航天大学