Lei Yucheng, Chang Hongxia, Guo Xiaokai, Li Tianqing, Xiao Longren
School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China.
School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China.
Ultrason Sonochem. 2017 Nov;39:77-86. doi: 10.1016/j.ultsonch.2017.03.038. Epub 2017 Mar 22.
Liquid lead-bismuth eutectic alloy (LBE) is applied in the Accelerator Driven transmutation System (ADS) as the high-power spallation neutron targets and coolant. A 19.2kHz ultrasonic device was deployed in liquid LBE at 550°C to induce short and long period cavitation erosion damage on the surface of weld joint, SEM and Atomic force microscopy (AFM) were used to map out the surface properties, and Energy Dispersive Spectrometer (EDS) was applied to the qualitative and quantitative analysis of elements in the micro region of the surface. The erosion mechanism for how the cavitation erosion evolved by studying the element changes, their morphology evolution, the surface hardness and the roughness evolution, was proposed. The results showed that the pits, caters and cracks appeared gradually on the erode surface after a period of cavitation. The surface roughness increased along with exposure time. Work hardening by the bubbles impact in the incubation stage strengthened the cavitation resistance efficiently. The dissolution and oxidation corrosion and cavitation erosion that simultaneously happened in liquid LBE accelerated corrosion-erosion process, and these two processes combined to cause more serious damage on the material surface. Contrast to the performance of weld metal, base metal exhibited a much better cavitation resistance.
液态铅铋共晶合金（LBE）在加速器驱动嬗变系统（ADS）中用作高功率散裂中子靶和冷却剂。将一台19.2kHz的超声装置置于550°C的液态LBE中，以在焊接接头表面引发短期和长期的空蚀损伤，利用扫描电子显微镜（SEM）和原子力显微镜（AFM）测绘表面特性，并应用能谱仪（EDS）对表面微观区域的元素进行定性和定量分析。通过研究元素变化、形态演变、表面硬度和粗糙度演变，提出了空蚀是如何发展的侵蚀机制。结果表明，经过一段时间的空蚀后，侵蚀表面逐渐出现凹坑、沟槽和裂纹。表面粗糙度随暴露时间增加。在孕育阶段，气泡冲击产生的加工硬化有效地增强了抗空蚀能力。液态LBE中同时发生的溶解与氧化腐蚀以及空蚀加速了腐蚀-侵蚀过程，这两个过程共同作用，对材料表面造成更严重的损伤。与焊缝金属的性能相比，母材表现出更好的抗空蚀能力。
