Effect of Nd:YAG pulsed laser welding process on the liquation and strain-age cracking in GTD-111 superalloy
Effect of Nd:YAG pulsed laser welding process on the liquation and strain-age cracking in GTD-111 superalloy
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DOI：
10.1016/j.jmapro.2020.01.049
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发表时间：
2020-04
影响因子：
6.2
通讯作者：
Guiju Zhang;Caiyuan Xiao;M. Taheri
中科院分区：
文献类型：
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作者：
Guiju Zhang;Caiyuan Xiao;M. Taheri
采用平均功率为250 W的Nd：YAG脉冲激光对GTD-111镍基高温合金进行了焊接性研究，并对焊接过程中的液化、凝固和应变时效裂纹特征进行了分析。结果表明，GTD-111镍基铸造高温合金中的液化裂纹与γ′相、MC碳化物、枝晶间γ-γ ′共晶的成分液化和富Cr硼化物的熔化有关。此外，在Al和Ti的浓度高的位置处发生焊接期间的裂纹。在MT 1条件下（1200℃，2 h），由于有害相在焊前溶解，焊缝无裂纹。在MT 1条件下，γ′相对裂纹的发生率影响不大。显微组织的分析表明，裂纹主要是由于熔析在焊态条件下，并加剧了焊后热处理裂纹在随后的热处理。焊接前经时效热处理的试样经时效热处理后，由于γ-γ共晶相析出，形成应变时效裂纹。显微硬度测试结果表明，熔合区的硬度高于热影响区和母材区。热影响区的液化裂纹主要受基体合金硬度的影响。
The weldability of GTD-111 nickel-based superalloy by Nd: YAG pulse laser with an average power of 250 W was studied using several pre-and post-weld heat treatment cycle, and the characteristics of liquation, solidification and strain-age cracks were also investigated. The results revealed that liquation cracks in the GTD-111 Nickel-Based Cast Superalloy were associated with the constitutional liquation of γ′ particle, MC carbides, inter-dendritic γ-γ׳ eutectic and melting of Cr-rich boride. Also, cracking during welding occurred at the places that the concentration of Al and Ti is high. Crack-free laser welds were observed in the MT1 conditions (1200℃ for 2 h) owing to dissolution of deleterious phases before welding. γ′ phase had little effect on the incidence of cracking in the MT1 condition. An analysis of the microstructures indicated that the cracking was caused primarily by liquation in the as-welded condition and was exacerbated by post-weld heat treatment cracking during the subsequent heat treatment. aging heat treatment of samples which were undergone aging heat treatment before welding, resulted in the formation of strain-age cracking due to γʹ and γ-γ׳ eutectic phases precipitation. The results of micro-hardness indicated that the hardness of fusion zone (FZ) was higher than that of HAZ and base metal zone (BMZ). The liquation cracking in the heat affected zone (HAZ) was observed to be affected by the hardness of base-alloy.