Effect of growth rate on microstructure and tensile properties of Ti–45Al–2Cr–2Nb prepared by electromagnetic cold crucible directional solidification
Effect of growth rate on microstructure and tensile properties of Ti–45Al–2Cr–2Nb prepared by electromagnetic cold crucible directional solidification
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DOI：
10.1016/j.matdes.2015.07.122
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发表时间：
2015-12
影响因子：
8.4
通讯作者：
H. Ding;Yong-zhe Wang;Ruirun Chen;Jingjie Guo;H. Fu
中科院分区：
文献类型：
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作者：
H. Ding;Yong-zhe Wang;Ruirun Chen;Jingjie Guo;H. Fu
采用电磁冷坩埚定向凝固技术，以0.2 ~ 1.2mm/min的不同生长速率对Ti-45 Al-2Cr-2Nb合金进行了定向凝固。结果表明，在柱状晶中生成了定向排列的α2（Ti 3Al）/γ（TiAl）片层组织、B2相和块状γ相。根据关系式λ <$V− 0.48，片层间距（λ）随着生长速率（V）的增加而减小，但B2的体积分数随着生长速率的增加而增加。单轴拉伸试验结果表明，当B2相和块状γ相存在于α2/γ层状组织基体中时，它们对拉伸破坏有显著影响，因为它们通常是拉伸过程中的裂纹源。
Ti–45Al–2Cr–2Nb alloy was directionally solidified at different growth rates varying from 0.2 to 1.2 mm/min by applying an electromagnetic cold crucible directional solidification technique. It was determined that well-aligned α2(Ti3Al)/γ(TiAl) lamellar structures, B2phase and blocky γ phase were generated in columnar grains. The interlamellar spacing (λ) decreases with the increasing growth rate (V) according to the relationship λ ∝V− 0.48, but the volume fraction of B2is increased as growth rate is increasing. Results of uniaxial tensile tests show that the B2phase and the blocky γ phase have significant influence on tensile failure when they are presented in the matrix of α2/γ lamellar structures, because they are usually employed to act as cracking sources during the tension process.