Liquation cracking behavior and control in the heat affected zone of GH909 alloy during Nd: YAG laser welding
Liquation cracking behavior and control in the heat affected zone of GH909 alloy during Nd: YAG laser welding
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DOI：
10.1016/j.jmatprotec.2017.01.018
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发表时间：
2017-06
影响因子：
6.3
通讯作者：
Fei Yan;Sang Liu;Chongjing Hu;Chunming Wang;Xiyuan Hu
中科院分区：
文献类型：
--
作者：
Fei Yan;Sang Liu;Chongjing Hu;Chunming Wang;Xiyuan Hu
本文叙述了GH909合金的激光焊接实验。研究了热影响区液化裂纹的形成机理，并对焊接工艺进行了改进。我们确定热影响区液化裂纹的发生经历了三个阶段：晶间液化、裂纹萌生和裂纹扩展。液化开裂的存在与低熔点共晶和在晶界处发生的成分偏析有关。偏析导致晶界晶格畸变，抑制了固/液界面的结合力。在激光焊接过程中，通过减少晶界处的热输入而产生的相对较薄的液体膜的迁移可以降低热影响区液化开裂的敏感性。采用固溶处理而非标准时效处理的GH909合金便于激光焊接，其力学性能明显降低。
In this paper, we describe experimental laser welding of GH909 alloy. The forming mechanism of heat affected zone (HAZ) liquation cracking was investigated and improvements to the welding process are proposed. We determined that the occurrence of HAZ liquation cracking proceeds through three stages: intergranular liquation, crack initiation and crack growth. The presence of liquation cracking is associated with low melting eutectics and composition segregation that occurs at the grain boundaries. The segregation caused lattice distortion at the grain boundaries and inhibited the binding force at the solid/liquid interface. The susceptibility to HAZ liquation cracking can be reduced by the migration of a relatively thin liquid film that is produced by reducing the heat input at the grain boundaries during laser welding. GH909 alloy in solid solution treatment condition rather than standard aging treatment was adopted to facilitate laser welding, which results in significantly lower mechanical.