In order to realize high-performance joining of misoriented single crystal superalloys, a rapid partial transient liquid phase (PTLP) bonding process was proposed in this work. By using a mixture of nickel-chromium-tantalum (Ni-Cr-Ta) and nickel-based superalloy (FGH4096) powders as filler material, high-performance PTLP joints of misoriented single crystal superalloys (DD5) were obtained. The joint bonded at 1260 °C consisted of an epitaxial growth zone (EGZ) containing γ/γ' derived from DD5 and a polycrystalline zone (PCZ) located at the center of the joining layer, in which tantalum dichromide (TaCr) and tantalum carbide (TaC) existed at the grain boundaries. As the Ni-Cr-Ta content increased, the voids in the joints decreased while the Ta-rich compounds increased and the grain size decreased. With the holding time increasing, the Ta-rich compounds decreased while the grain size increasing. The optimum process was 60 min at 1260℃ with the Ni-Cr-Ta content of 60 wt%. Due to the specially designed filler metal without boron (B) and silicon (Si) elements, there was no low-melting eutectic or compound in the PTLP joints, which ensure the joint with high-performance at elevated temperatures. Compared with transient liquid phase (TLP) bonding process, the PTLP bonding process achieved rapid isothermal solidification with the help of the short-distance and large-area diffusion mechanism between the Ni-Cr-Ta (liquid phase) and FGH4096/DD5. The presence of PCZ prevented the formation of penetrating grain boundary, and thus eliminated the effect of misorientation between two base metals on the performance of the joints. The tensile strengths at room temperature and 980 °C of the PTLP joints which obtained with the optimum process were 926.05 MPa and 681.96 MPa, respectively, up to 90.32% and 92.25% of the base metal. The PTLP bonding process proposed in the present work may provide a high efficiency approach to achieve high-performance single crystal superalloy joint, which is also gifted a major advantage of B/Si-free.

中文翻译：

---

通过镍-铬-钽和镍基高温合金粉末的混合物对错误取向的单晶高温合金进行部分瞬态液相结合

为了实现错误取向单晶高温合金的高性能连接，本文提出了一种快速部分瞬态液相（PTLP）连接工艺。采用镍铬钽（Ni-Cr-Ta）和镍基高温合金（FGH4096）粉末的混合物作为填充材料，获得了高性能的错取向单晶高温合金（DD5）PTLP接头。在 1260 °C 下接合的接头由含有源自 DD5 的 γ/γ' 的外延生长区 (EGZ) 和位于接合层中心的多晶区 (PCZ) 组成，其中二铬化钽 (TaCr) 和碳化钽(TaC)存在于晶界处。随着Ni-Cr-Ta含量的增加，接头中的空隙减少，富Ta化合物增加，晶粒尺寸减小。随着保温时间的延长，富Ta化合物减少，晶粒尺寸增大。最佳工艺为1260℃、60 min、Ni-Cr-Ta含量为60 wt%。由于特殊设计的填充金属不含硼（B）和硅（Si）元素，PTLP接头中不存在低熔点共晶或化合物，从而保证了接头在高温下的高性能。与瞬态液相（TLP）键合工艺相比，PTLP键合工艺借助Ni-Cr-Ta（液相）与FGH4096/DD5之间的短距离、大面积扩散机制实现了快速等温凝固。PCZ的存在阻止了穿透晶界的形成，从而消除了两种母材之间的取向差对接头性能的影响。采用优化工艺得到的PTLP接头的室温和980℃拉伸强度分别为926.05 MPa和681.96 MPa,分别达到母材的90.32%和92.25%。本工作中提出的PTLP接合工艺可以提供一种高效的方法来实现高性能单晶高温合金接头，这也具有无B/Si的主要优点。