TC11钛合金单道选区激光熔化成形机理与工艺参数影响规律

Mechanism and influence of process parameters on single track selective laser melting forming of TC11 titanium alloy

为探明TC11钛合金选区激光熔化成形规律,以获得高质量TC11钛合金增材制造参数,本文基于离散单元法建立粒径呈高斯分布的粉末层,并将其通过UDF导入到Fluent软件,建立介观尺度下的选区激光熔化CFD模型,对不同工艺参数下的单道形貌缺陷以及熔池演变过程进行模拟,阐明TC11钛合金单道选区激光熔化成形机理,并结合实验验证仿真模型的准确性.结果表明:当能量密度较小时,部分粒径较大或较为集中的粉末无法吸收足够的能量后熔化,故易产生球化或单道不平直等缺陷;在相同线能量密度下,过高扫描速度也会导致缺陷形成,且实验和仿真误差在15%以内.研究结果可为提高TC11增材制造质量和工艺参数优化提供依据.

In order to find out the law of selective laser melting forming of TC11 titanium alloy and obtain high quality additive manufacturing parameters of TC11 titanium alloy,a powder layer with Gaussian particle size distribution is established based on discrete element method and imported into Fluent software through UDF to establish a mesoscopic selective laser melting CFD model.The morphology defects of single track and the evolution process of molten pool with different process parameters are simulated,and the forming mechanism of single track selective laser melting of TC11 titanium alloy is clarified.The accuracy of the simulation model is verified by experiments.The results show that when the energy density is small,some powders with larger or more concentrated particle size cannot absorb enough energy and melt,so it is easy to produce defects such as spheroidization or single channel irregularity.Under the same linear energy density,high scanning speed will also lead to the formation of defects and experimental and simulation errors within 15%.The results provide a basis for improving the additive manufacturing quality of TC11 and optimizing the process parameters.