Effects of Hf and B on high temperature low stress creep behavior of a second generation Ni-based single crystal superalloy DD11
Effects of Hf and B on high temperature low stress creep behavior of a second generation Ni-based single crystal superalloy DD11
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DOI：
10.1016/j.msea.2016.06.079
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发表时间：
2016-08
期刊：
影响因子：
6.4
通讯作者：
Y. Zhao;J. Zhang;Y. Luo;Jinxu Li;D. Tang
中科院分区：
文献类型：
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作者：
Y. Zhao;J. Zhang;Y. Luo;Jinxu Li;D. Tang
研究了四种镍基单晶高温合金的铸态和热处理组织及高温蠕变性能，其中Hf含量为0~0.4wt%，B含量为0~0.02wt%。实验结果表明，单独添加Hf可提高蠕变持久寿命，但单独添加B会降低蠕变持久寿命。单独添加Hf或B会明显改变γ/γ‘的元素分配比和界面位错间距。同时，在蠕变样品中观察到了块状MC碳化物、脚本状M3B2相等第二相的形成，这也与高温蠕变行为密切相关。残余(γ+γ‘)共晶体积分数高的主要原因是同时添加Hf和B的实验合金的蠕变持久寿命显著降低。该研究有助于更好地理解Hf和B的强化机制，优化单晶高温合金中Hf和B的加入量。
The as-cast and heat-treated microstructures and high temperature creep properties have been investigated in four experimental Ni-based single crystal superalloys containing various levels of Hf addition (0–0.4 wt%) and B addition (0–0.02 wt%). The experimental results indicated that the creep rupture life showed an improvement with individual addition of Hf, but it was decreased with individual addition of B. The elemental partitioning ratio and interfacial dislocation spacing of γ/γ′ were obviously changed with individual Hf or B additions. Meanwhile, the formation of secondary phases, such as the blocky MC carbide, script-like shape M3B2phases, was observed in the creep samples, which was also closely related to the high temperature creep behaviors. The high volume fraction of residual (γ+γ′) eutectics was mainly attributed to the significant decrease of creep rupture life for the present experimental alloy containing both Hf and B additions. This study is helpful to better understand Hf and B's role of strengthening mechanism and to optimize Hf and B additions in single crystal superalloys.