Experimental Investigation on Laser Metal Deposition of Ti-6Al-4V Alloy with Coaxial Local Shielding Gas Nozzle
Experimental Investigation on Laser Metal Deposition of Ti-6Al-4V Alloy with Coaxial Local Shielding Gas Nozzle
复制标题
同轴局部保护气喷嘴激光金属沉积Ti-6Al-4V合金的实验研究
DOI：
10.1007/s11665-020-05283-x
复制
发表时间：
2020-11-13
影响因子：
2.3
通讯作者：
Shi, Shihong
中科院分区：
文献类型：
--
作者：
Li, Gang;Zhang, Jinchao;Shi, Shihong
由于钛合金的氧化，在激光金属沉积过程中需要惰性气体环境。带有局部屏蔽装置的喷嘴比惰性气室更灵活，生产的部件大小不受限制。在本研究中，设计了一种同轴双层气体屏蔽喷嘴，为激光沉积钛铝4V合金提供局部屏蔽。对四种不同气体流量下的流场进行了数值模拟，得到了相应的Ti-6Al-4V单层包层和构件。实验结果表明，随着气体流量的增大，有效保护长度先增大后趋于稳定。各组分的表面变色程度均有明显变化。其中，当气体流量超过30 L/min时，成形的块体成分表面呈淡黄色有光泽的银色，内部氧含量低于2000ppm，与粉末相比上升幅度很小。此外，与轧制基材相比，零件的显微硬度几乎没有增加。
An inert gas environment is required during the laser metal deposition of titanium alloys due to oxidation. A nozzle with local shielding device is more flexible than the inert gas chamber, and size of the components produced is not restricted. In this study, a coaxial double-deck gas shielding nozzle was designed to provide a local shielding for the laser metal deposition of Ti-6Al-4V alloy. Numerical simulation of flow field under four different gas flow rates was carried out, and the corresponding Ti-6Al-4V single clads as well as components were produced. Experimental results revealed that the effective protection length increased and then became steady with the gas rate getting larger. Every component showed significant change in the degree of surface discoloration. Among that when the gas flow rate exceeded 30 L/min, surface of the formed bulk components showed yellowish and shiny silver and the internal oxygen content was below 2000 ppm, which had a minimal raise from the powder. In addition, the microhardness of the components showed little increase compared with the rolled substrate.