Abstract:

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.

Key words: ITER, First wall, Be/Cu, Ti/Cu, Hot isostatic pressing (HIP), Annealing

摘要：

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。

关键词: ITER, 第一壁, 铍铜热等静压, 钛铜扩散界面, 退火