Ultrasonic test of carbon composite/copper joints in the ITER divertor
Ultrasonic test of carbon composite/copper joints in the ITER divertor
复制标题
ITER 偏滤器中碳复合材料/铜接头的超声波测试
DOI：
10.1016/j.fusengdes.2013.05.078
复制
发表时间：
2013
影响因子：
1.7
通讯作者：
E. Visca
中科院分区：
文献类型：
--
作者：
S. Roccella;E. Cacciotti;D. Candura;A. Mancini;A. Pizzuto;A. Reale;A. Tatì;E. Visca
ITER偏滤器的垂直靶由主动冷却的高通量单元（HFU）组成：由钨和碳/碳纤维复合材料（CFC）铠装的CuCrZr管。装甲是用有孔的平行六面体块获得的，称为单块，预先制备并通过扩散结合焊接到管上。单块制备包括在单块孔内铸造一层无氧铜（Cu OFHC）。每个HFU覆盖有100多个单块，这些单块必须同时连接到管上。因此，在机组安装前，对铜OFHC铸件中或与CFC的界面处存在的任何缺陷进行个体化处理是非常重要的。本文讨论了超声无损检测方法在CFC整体与铜OFHC连接界面控制中的应用。在ENEA实验室，根据ITER规范，开发并广泛测试了适用于控制这些接头尺寸和几何形状的超声技术（UT）。然而，UT仍然很难检测到此类接头中的真实的缺陷。CFC表面必须进行机加工以提高接头的机械强度。这导致表面不垂直于超声波。此外，CFC的特征在于超声波的高声学衰减，因此不容易获得关于Cu/CFC键合的信息。然而，UT的清晰度和简单性推动了进一步的研究。有了这个目的，与人工缺陷的CFC/Cu界面上引起的铜铸造过程中，样品已被制造和研究，无论是通过脉冲回波技术和不同的技术。本文报道了该样品的超声检测结果，并与X射线法进行了比较。
The vertical targets of the ITER divertor consist of high flux units (HFU) actively cooled: CuCrZr tubes armoured by tungsten and carbon/carbon fibre composite (CFC). The armour is obtained with holed parallelepiped blocks, called monoblocks, previously prepared and welded onto the tubes by means diffusion bonding. The monoblock preparation consists in the casting of a layer of copper oxygen free (Cu OFHC) inside the monoblock hole.Each HFU is covered with more than 100 monoblocks that have to be joined simultaneously to the tube. Therefore, it is very important to individuate any defects present in the casting of Cu OFHC or at the interface with the CFC before the monoblocks are installed on the units.This paper discusses the application of non-destructive testing by ultrasound (US) method for the control of the joining interfaces between CFC monoblocks and Cu OFHC, before the brazing on the CrCrZr tube.In ENEA laboratory an ultrasonic technique (UT) suitable for the control of these joints with size and geometry according to the ITER specifications has been developed and widely tested. Real defects in this type of joints are, however, still hardly detected by UT. The CFC surface has to be machined to improve the mechanical strength of the joint. This results in a surface not perpendicular to the ultrasonic wave. Moreover, CFC is characterized by high acoustic attenuation of the ultrasonic wave and then it is not easy to get information regarding the Cu/CFC bonding. Nevertheless, the UT sharpness and simplicity pushes to perform some further study. With this purpose, a sample with artificial defects induced on the CFC/Cu interface during the Cu casting, has been manufactured and investigated, both by pulse-echo technique and by different techniques. The results obtained by the UT on this sample are reported and compared with X-ray method.