Grain structure development in directional solidification of nickel-base superalloys
Grain structure development in directional solidification of nickel-base superalloys
复制标题
DOI：
10.1016/j.msea.2004.03.017
复制
发表时间：
2004-06
期刊：
影响因子：
6.4
通讯作者：
A. Wagner;B. Shollock;M. Mclean
中科院分区：
文献类型：
--
作者：
A. Wagner;B. Shollock;M. Mclean
三个单晶高温合金（CMSX 4，CM186LC和CMSX 10），表现出相当不同的铸造性能的微观结构进行了定量表征淬火定向凝固，以确定晶粒选择机制的变化。合金的枝晶形貌没有观察到显着差异。详细观察枝晶在定向凝固的双晶体CMSX 4与良好控制的取向差显示显着修改的二次枝晶的生长在发展中的籽晶晶界。普遍接受的二次枝晶过度生长的标准不能解释目前的结果。有人提出，经常在第二代和第三代高温合金中产生的扩散纹理是由于竞争的溶质扩散场抑制二次枝晶发展的结果。
The microstructures of three single crystal superalloys (CMSX4, CM186LC and CMSX10) that exhibit quite different casting properties have been characterised quantitatively following quenched directional solidification to identify variations in the grain selection mechanisms. No significant differences in the dendrite morphologies of the alloys were observed. Detailed observation of dendrites in directionally solidified bicrystals of CMSX4 with well-controlled misorientations showed significant modification of the growth of secondary dendrites at the developing seeded grain boundary. The generally accepted criterion of overgrowth by secondary dendrites cannot account for the present results. It is proposed that the diffuse textures that are frequently produced in second and third generation superalloys are a consequence of the inhibition of secondary dendrite development due to competing solute diffusion fields.