Effect of substrate orientation on the formation of equiaxed stray grains in laser surface remelted single crystal superalloys: Experimental investigation
Effect of substrate orientation on the formation of equiaxed stray grains in laser surface remelted single crystal superalloys: Experimental investigation
复制标题
基体取向对激光表面重熔单晶高温合金中等轴杂散晶粒形成的影响：实验研究
DOI：
10.1016/j.actamat.2015.11.018
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发表时间：
2016-02-01
期刊：
影响因子：
9.4
通讯作者：
Wang, N.
中科院分区：
文献类型：
--
作者：
Wang, L.;Wang, N.
基体取向对单晶合金激光焊接中杂散晶粒的形成起着关键作用，而杂散晶粒的形成对单晶合金激光焊接件的成功修复至关重要。在先前的工作[Acta Mater 2015; 88：283-292]中，我们通过围绕x-、y-和z-轴旋转改变取向，从理论上研究了基板取向对激光熔池中等轴SG磁化率的影响，x-、y-和z-轴分别与[100]、[010]和[001]结晶方向一致。发现y轴旋转导致SG能力的强烈变化，而x轴和z轴旋转几乎没有影响。在这项研究中，进行了实验，以验证计算结果。本文以我国第二代SX高温合金DD 6为研究对象。确定了与取向相关的SG形成，并采用SG的面积平均体积分数来评估整体CET趋势。取向相关SG的实验趋势与理论预测一致。成本psi分布进一步揭示了衬底取向对SG形成的影响，其中psi是一个几何参数，其是凝固前沿的法向矢量与枝晶畴中的择优结晶方向之间的角度。我们的研究结果提供了一个深入的洞察到通过调整基板取向的SX修复的激光加工窗口的控制。(C)2015 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Substrate orientation could play a key role in the stray grain (SG) formation in laser welded single crystal (SX) alloys, which is critical to a successful repair of SX components. In a previous work [Acta mater 2015; 88:283-292], we studied theoretically the substrate orientation effect on equiaxed SG susceptibility in laser melt pools by altering the orientation via rotations around x-, y-, and z-axis, which coincide with the [100], [010], and [001] crystallographic directions, respectively. It was found that y-axis rotation leads to a strong variation in SG ability whereas x- and z-axis rotations nearly have no effect. In this study, experiments were conducted to verify the calculated results. DD6, a second-generation Chinese SX superalloy was chosen as the object of research. The orientation-dependent SG formation was determined and the area-average volume fraction of SGs was employed to evaluate the overall CET tendency. The experimental tendency of the orientation dependent SG agrees well with the theoretical prediction. The effect of the substrate orientation on SG formation was further revealed by cost psi distribution, where psi is a geometrical parameter which is the angle between normal vector to the solidification front and preferred crystallographic direction in dendrite domain. Our results provide an in-depth insight into the control of laser processing window for SX repair via adjusting the substrate orientation. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.