Abstract:

The brazing process of chlorofluorocarbon/oxygen-free-copper (CFC/OFC) composite mockup and CuCrZr at 710~750°C by vacuum brazing and with STEMET-1101 amorphous filler is studied. Firstly, the microstructure and melt behaviors of the filler are characterized by means of XRD and differential scanning calorimetry and then the organism form, elemental distributions, phase structures, and mechanical property in the bonding seams are studied by using optical microscopy, electron probe microanalysis and tensile tests. The thermal fatigue property of CFC/OFC/CuCrZr brazing mockup is measured with the high heat flux facility. The results show that the bonding seam consists of Ni(Cr, Cu)2P particles, Cu(Ni)3P phase and Cu matrix in brazing temperature of 710~750°C, which is smooth and crack-free. Especially, a continued intermetallic phase network in the bonding seam is depressed in the case of 750°C/15min treatment. The welding strength of the OFC/CuCrZr is higher than tensile strength of OFC. The bonding strength of CuCrZr/CuCrZr joint is 210MPa and fracture is partly ductile. The CFC/Cu/CuCrZr mockup prepared in the case of 750°C/15min treatment can tolerate 7MW·m^-2 high heat flux under 1000 cycles.

Key words: HL-2M divertor, Amorphous filler, Brazing, High heat flux tests

摘要：

在采用商用的STEMET-1101非晶钎料、温度为710~750°C的真空钎焊下，对CFC/OFC(氯氟烃/无氧铜)复合块与CuCrZr(铬锆铜)的钎焊进行了研究。首先，通过X-射线衍射(XRD)和差式扫描量热分析对钎料的结构和熔化行为进行了表征；然后，通过光学显微镜、电子探针微分析和拉伸试验等方法对焊缝的组织形貌、元素成分分布、相结构和力学性能进行了分析；最后，通过高热负荷装置对CFC/OFC/CuCrZr钎焊模块的热疲劳性能进行测试。结果表明，在710~750°C钎焊温度内焊缝由Cu固溶体、(Cu, Ni)3P和Ni(Cu ,Cr)2P金属间化合物组成，焊缝平整无裂纹；特别是在750°C/15min情况下，抑制了焊缝金属间化合物的连续分布，OFC/CuCrZr的焊接强度大于OFC的抗拉强度，CuCrZr/CuCrZr的结合强度为210MPa，并呈现部分韧性断裂。在750°C/15min情况下制备的CFC/Cu/CuCrZr模块可以承受1000次7MW·m^-2的循环热负荷。

关键词: HL-2M divertor, Amorphous filler, Brazing, High heat flux tests