Enhancement of multi-pass weld-crack resistance of Co-based superalloys by B-doping
Enhancement of multi-pass weld-crack resistance of Co-based superalloys by B-doping
复制标题
B掺杂增强钴基高温合金多道焊缝抗裂性能
DOI：
10.1016/j.matchar.2021.111527
复制
发表时间：
2021-10
影响因子：
4.7
通讯作者：
Zhou Yizhou
中科院分区：
文献类型：
--
作者：
Wen Mingyue;Sun Yuan;Yu Jinjiang;Meng Jie;Wang Shiyang;Dong Zhiguo;Niu Juntao;Sun Xiaofeng;Zhou Yizhou
提高钴基超级合金的抗焊裂性能具有重要的科学意义和现实意义。本文研究了Co-9.2Al-9 W-xB (at。%, x = 0, 0.05, 0.20)高温合金在多道次熔焊中的应用。结果表明，当b掺杂量为0.20%时，焊缝裂纹在熔合区形成。而加入0.05% B合金的高温合金焊接后没有出现裂纹，说明少量B掺杂可以提高co基高温合金的抗焊接裂纹能力。阐明了三种钴基高温合金不同可焊性的机理。b -掺杂0.05 at。%时，μ-Co7W6相在晶界上的析出被完全抑制，内部残余应力大大降低。0.05%硼含量的高温合金具有抑制析出相和降低内应力的特点，其抗焊接裂纹性能显著提高。而当b掺杂量达到0.20%时，M3B2相在晶界处析出，晶粒内部应力增大，可焊性进一步恶化。这些发现将促进高抗焊接裂纹钴基高温合金的发展。
Enhancing weld-crack resistance of Co-based suerpalloys is of both scientific and practical significance. In this work, the fusion zone weld-crack resistance of Co-9.2Al-9 W-xB (at.%, x = 0, 0.05, 0.20) superalloys during multi-pass fusion welding is investigated. It is found that weld cracks form in fusion zone without B-doping and with B-doping of 0.20%. However, no cracks form in the welded superalloy with 0.05% B alloys, suggesting the weld-crack resistance of Co-based superalloys can be enhanced by a small amount of B-doping. The mechanisms underlying the different weldability of the three Co-based superalloys are clarified. With B-doping of 0.05 at.%, the precipitation of μ-Co7W6 phase on grain boundaries can be fully suppressed, and the internal residual stress is largely reduced. The suppression of precipitated phases and low internal stress in the superalloy with 0.05% Bdoping account for its much enhanced weld-crack resistance. However, with further B-doping of 0.20%, the M3B2 phase precipitates on the grain boundaries and the internal stress inside grains also increases, which account for the further deterioration of weldabilty. These findings are believed to promote the development of Co-based superalloys with high weld-crack resistance.