退火对钛/铜热等静压扩散连接界面的影响

钛/铜(Ti/Cu)作为ITER 第一壁Be/CuCrZr 热等静压连接中间过渡层，形成了多层中间金属相结构，容易在Ti/Cu 金属相之间产生裂纹等缺陷。采用CuCrZr 代替Be，经过与Be/CuCrZr 相同的热等静压工艺，制作了多个CuCrZr/Ti/Cu/CuCrZr 连接件，对Ti/Cu 连接接头进行深入分析。对连接件分别进行未退火、400℃和500℃ 退火处理，去应力退火后对接头强度和缺陷分布的影响进行了研究。研究结果表明，中间钛层的两侧都形成了三层Ti/Cu 扩散层，分别为Cu₄Ti、CuTi 和CuTi₂。纯铜侧的Cu₄Ti 厚度比CuCrZr 侧的厚，使得裂纹几乎全部分布于铜侧的Cu₄Ti 与CuTi 交界处，拉伸样品极易在此处发生脆性断裂。随着退火温度升高，裂纹的产生和扩展减少。

Effect of annealing on Ti/CuCrZr HIP interface

As the ITER first wall Be/CuCrZr hot isostatic pressing (HIP) bonding intermediate transition layer, Ti/Cu layer can form a multi-layer intermediate metal phase, and defects such as cracks occur between the Ti/Cu metal phases. CuCrZr was used instead of Be, and a number of CuCrZr/Ti/Cu/CuCrZr joints were fabricated by the same HIP process as Be/CuCrZr to analyze the Ti/Cu joints. The effects of stress relief annealing on joint strength and defect distribution of the joints unannealed, annealed at 400°C and 500°C respectively were studied. The results show that three layers of Ti/Cu diffusion layers are formed on both sides of the intermediate titanium layer, namely Cu₄Ti, CuTi and CuTi₂. The thickness of Cu₄Ti on the pure copper side is thicker than that on the CuCrZr side, so that the crack is almost entirely distributed at the junction of Cu₄Ti and CuTi on the pure copper side where brittle fracture is easy to occur in the tensile samples. As the annealing temperature increases, the generation and propagation of cracks decreases.