Brazing C/C composites to DD3 alloy with a novel Ag–Cr active braze
Brazing C/C composites to DD3 alloy with a novel Ag–Cr active braze
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DOI：
10.1016/j.ceramint.2022.02.038
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发表时间：
2022-02
影响因子：
5.2
通讯作者：
Xiajun Guo;X. Si;Chun Li;Shuhui Zhao;Bo Yang;J. Qi;Jian Cao
中科院分区：
文献类型：
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作者：
Xiajun Guo;X. Si;Chun Li;Shuhui Zhao;Bo Yang;J. Qi;Jian Cao
提出了一种新型的Ag-Cr活性钎料，成功地将碳/碳（C/C）复合材料钎焊到镍基单晶合金（DD 3）上。研究了C/C-AgCr-DD 3焊接接头的组织特征和力学性能。结果表明，在C/C和DD 3基体附近分别存在Cr23 C6和Ni 2Cr层。Cr颗粒聚集在Ni 2Cr层外。令人惊讶的是，只有Ag基体和Cr颗粒可以观察到在钎焊焊缝中没有形成脆性化合物，避免了对接头塑性的损害。随着Cr含量的增加和钎焊温度的升高，Cr23 C6和Ni 2Cr层的厚度增加。过高的钎焊温度导致钎焊缝急剧变窄。纳米压痕测试表明，Cr23 C6相的硬度和弹性模量最高，分别为22.5 GPa和316 GPa。在1040 °C下使用Ag-10 wt% Cr钎焊获得接头剪切强度的最大值（27 MPa）。该研究有助于揭示界面微观结构对C/C-金属接头性能的影响，进一步促进接头的可靠使用。此外，本研究提供了一种新的钎焊设计策略，以避免在C/C复合材料和镍基合金的接头中形成脆性化合物。
A novel Ag–Cr active braze is presented to successfully braze carbon/carbon (C/C) composites to a Ni-based single crystal alloy (DD3). The microstructural characteristics and mechanical properties of C/C–AgCr-DD3 joints are investigated. Results indicate that Cr23C6and Ni2Cr layers can be found nearby C/C and DD3 substrates, respectively. And Cr particles are aggregated outside the Ni2Cr layer. Amazingly, only Ag matrix and Cr particles can be observed in the brazed seam without the formation of brittle compounds, avoiding damage to the joint plasticity. The thickness of Cr23C6and Ni2Cr layers can be increased with increasing Cr content and brazing temperature. The excessive brazing temperature results in a sharp narrowing of the brazed seam. The nano-indentation test shows that the Cr23C6phase exhibits the highest hardness (22.5 GPa) and elastic modulus (316 GPa) among joint phases. The maximum value (27 MPa) of the joint shear strength is obtained using Ag-10 wt% Cr braze at 1040 °C. This work can facilitate revealing effects of the interfacial microstructure on the performance of C/C-metal joints, further promoting their reliable utilization. Furthermore, this study provides a new braze design strategy to avoid the formation of brittle compounds in joints of C/C composites and Ni-based alloy.