To fabricate large-sized and complex-shaped ceramic components for service at elevated temperatures, (HfZrTiTaNb)C high-entropy ceramic (HEC) joints with the improved joint strength of 292 MPa were successfully realized by using a FeCoCrNiTi_0.2 high-entropy alloy (HEA) filler at 1430 °C. The reliable joint relied on a direct metallurgical bonding with semi-coherent interfaces between HEC' carbides and HEA' alloy, independent of compounds. The high-entropy interface was confirmed by the habit planes of (020)_HEC' // (020)_HEA' and the calculated lattice misfit of 1.58%, which represented small internal stresses at bonding interfaces in the joints. The formation of HEC and HEA phases originated from the direct phase transition of HEC induced by active Ti and the residual of liquid HEA, respectively, and they maintained their original lattice structures, nanohardness, and elastic modulus. The joints possessed undiminished strength values when tested at 1000 °C, benefiting from high-entropy microstructures throughout the interfacial region. The failure location migrated from the HEC near the HEC' to the HEA'. In addition, the interfacial formation strategy was investigated by altering HEA thicknesses and bonding times. The HEC' was invariably present in the joint, while preventing phase separation of liquid HEA upon cooling to form HEC'/HEA'/HEC' structure required the HEA thickness of at least 300 µm and the resulting abundant liquid filling. With extended bonding times of up to 60 min, the depletion of the HEA' layer would decrease joint strength by 140 MPa. This work provides a new perspective on joint design toward ∼1000 °C high-temperature applications.

为了制造高温下使用的大型复杂形状陶瓷部件，采用FeCoCrNiTi _0.2 // (020) _HEA' 的习惯平面和计算出的 1.58% 的晶格失配证实，这表示键合时的内应力较小关节中的界面。 HEC和HEA相的形成分别源于活性Ti和液态HEA残留诱导HEC的直接相变，并且它们保持了原有的晶格结构、纳米硬度和弹性模量。受益于整个界面区域的高熵微观结构，在 1000 °C 下测试时，接头具有不降低的强度值。故障位置从HEC'附近的HEC迁移到HEA'。此外，通过改变 HEA 厚度和键合时间研究了界面形成策略。 HEC' 总是存在于接头中，同时防止液体 HEA 在冷却时发生相分离，以形成 HEC'/HEA'/HEC' 结构，需要至少 300 µm 的 HEA 厚度以及由此产生的丰富液体填充。当粘合时间延长至 60 分钟时，HEA' 层的损耗将使接头强度降低 140 MPa。这项工作为~1000 °C 高温应用的接头设计提供了新的视角。