Effect of nitrogen content on microstructure and fatigue crack growth rate of high titanium-alloyed superalloy
Effect of nitrogen content on microstructure and fatigue crack growth rate of high titanium-alloyed superalloy
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DOI：
10.1016/j.matchar.2020.110492
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发表时间：
2020-09
影响因子：
4.7
通讯作者：
Gao Xiaoyong-;Lin Zhang;Chen Xiaowei-;Luan Yifeng;X. Qu
中科院分区：
文献类型：
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作者：
Gao Xiaoyong-;Lin Zhang;Chen Xiaowei-;Luan Yifeng;X. Qu
研究了氮含量对高钛镍基高温合金FGH96显微组织和疲劳裂纹扩展速率的影响。结果表明：当含氮量从0.0066 wt%降低到0.0012 wt%时，组织（γ′相和碳化物）变化不大，但FCG速率显著降低；这可以用氮化TiN的尖锐和矩形形貌来解释，这可能导致其周围严重的应力集中。在高含氮合金的横截面上，沿主裂纹路径和次裂纹路径分布有TiN氮化物。采用扫描电镜（SEM）和透射电镜（TEM）结合能谱仪（EDS）分析了TiN氮化物的特征。随着氮含量的降低，TiN氮化物的数量密度、面积分数、最大尺寸和平均尺寸均减小。氮含量为66 ppm时，存在较大尺寸的TiN团簇。
The effect of nitrogen content on microstructure and fatigue crack growth (FCG) rate of high titanium-alloyed Ni-based superalloy FGH96 was investigated. The results show that with nitrogen content decreasing from 0.0066 wt% to 0.0012 wt%, the microstructure (γ' phase and carbide) has little change, but the FCG rate decreases significantly. This can be explained by the sharp and rectangular morphology of TiN nitride, which could cause severe stress concentration around them. TiN nitrides were observed along the main and secondary crack paths on the transversal section of alloys with high nitrogen content. The characteristic of TiN nitrides was analyzed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDS). The number density, area fraction, and maximum and average sizes of TiN nitrides decrease with decreasing of nitrogen content. Clusters of TiN with large size exist in the case of 66 ppm of nitrogen.