Abstract: The dipole magnet vacuum pipeline was critical equipment for the booster ring of HIAF. In order to attenuate the eddy current effect, reduce the gap of magnet, and decrease the difficulty of vacuum pipeline machining, the 3D-printed titanium alloy-lined ring wrapped in stainless steel with a thickness of 0.3 mm was created for fabricating a thin-wall chamber. The structural optimization of the titanium alloy-lined ring was carried out through simulation, and thin-wall chambers were fabricated for deformation testing and high-temperature baking testing. Evaluation of the outgassing performance of 3D-printed titanium alloy was completed. Ultimate vacuum tests were conducted before and after coating thin-wall chamber with Ti-Zr-V films, and a study of the effect of eddy current on vacuum performance was carried out. The results show that the stresses of stainless steel and titanium alloy are below the strength limit when the thickness of the titanium alloy-lined ring is as 4 mm, the width is as 11 mm and the spacing is as 15 mm. The deformation of the ring, with an arch height of 0.5 mm, is measured to be 0.78 mm, and the structure remained stable after 35 rounds of high-temperature baking at 250 ℃. The outgassing performance of TC4 titanium alloy and the ultimate vacuum performance of the thin-wall chamber meet the design criteria.

Key words: high intensity heavy-ion accelerator facility（HIAF）, titanium alloy-lined thin-wall chamber, 3D-printing, structure optimization, vacuum performance

摘要： 二极磁铁真空管道是强流重离子加速器装置增强器的关键设备，为了降低涡流效应、减小磁铁气隙及降低真空管道加工难度，采用厚度为0.3 mm的不锈钢包裹3D打印钛合金内衬骨架制作薄壁腔体。通过仿真模拟对内衬骨架进行结构优化设计，制作薄壁腔体进行变形量测试和高温烘烤强度测试。完成了3D打印钛合金出气性能评价、薄壁腔体镀Ti-Zr-V薄膜前后极限真空测试和涡流发热对真空性能影响的研究。研究结果表明，内衬骨架厚度为4 mm、宽度为11 mm、间距为15 mm时，不锈钢和钛合金应力小于强度极限；拱形高度为0.5 mm的内衬骨架实测变形量为0.78 mm，经过35次250 ℃高温烘烤后结构稳定；TC4钛合金材料的出气性能和薄壁腔体的极限真空性能满足设计指标要求。

关键词: 强流重离子加速器装置, 钛合金内衬薄壁腔体, 3D打印, 结构优化, 真空特性