金属增材制造中基于温度-发射率分离的辐射测温
Radiometric Temperature Measurement for Metal Additive Manufacturing via Temperature Emissivity Separation
AI总结：
针对LPBF光学监测仪器难以可靠检测细微缺陷的问题，提出温度-发射率分离（TES）方法，通过同时反演温度和光谱发射率提升测温精度，实验验证精度达±28 K，还证明工业可行性并实现微米级孔隙缺陷原位检测。
摘要：
激光粉末床熔融（LPBF）中熔池及周边区域的黑体辐射使该过程可被多种用于在线过程和质量控制的光学监测仪器观测。然而，这些仪器尚未能可靠检测影响LPBF构件力学性能的细微缺陷，限制了其应用。尽管辐射亮度与温度的物理联系可通过普朗克定律和光谱发射率的组合轻松理解，但将辐射亮度测量值解读为温度仍存在障碍。光谱发射率的不确定性源于其几乎无法预测且是波长的强函数；这进而导致估计温度的不确定性，掩盖了指示构件缺陷的LPBF过程动态。本文提出温度-发射率分离（TES）方法，用于准确反演LPBF中的光学测量温度。TES从光谱分辨辐射亮度测量值中同时计算温度和光谱发射率，由于后者被有效测量，因此得到更准确的过程温度。通过集成于LPBF试验台的定制成像光谱仪评估该方法，在验证实验中比较三种基本TES算法，结果显示在1000 K范围内温度反演精度达±28 K。第二项研究通过制造LPBF测试工件证明工业可行性，利用温度数据研究熔合过程边界条件的演变（包括分层打印时冷却速率降低），并通过3D计算机断层扫描评估温度场与构件孔隙率的初步关联，实现LPBF中微米级孔隙缺陷的原位光学检测。
英文摘要：
Emission of blackbody emission from the meltpool and surrounding area in laser powder bed fusion (LPBF) makes this process visible to a range of optical monitoring instruments intended for online process and quality control. Yet, these instruments have yet to prove capable of reliably detecting the finest flaws that influence LPBF component mechanical performance, limiting their adoption. One hindrance lies in interpreting measurements of radiance as temperature, despite the physical link between these variables being readily understood as a combination of Plank's Law and spectral emissivity. Uncertainty in spectral emissivity arises as it is nearly impossible to predict and can be a strong function of wavelength; in turn, this manifests uncertainty in estimated temperatures and thereby obscures the LPBF process dynamics that indicate component defects. This paper presents temperature emissivity separation (TES) as a method for accurate retrieval of optically-measured temperatures in LPBF. TES simultaneously calculates both temperature and spectral emissivity from spectrally-resolved radiance measurements and, as the latter term is effectively measured, more accurate process temperatures result. Using a bespoke imaging spectrometer integrated with an LPBF testbed to evaluate this approach, three basic TES algorithms are compared in a validation experiment that demonstrates retrieval of temperatures accurate to $\pm 28$ K over a $1000$ K range. A second investigation proves industrial feasibility through fabrication of an LPBF test artifact. Temperature data are used to study the evolution of fusion process boundary conditions, including a decrease in cooling rate as layerwise printing proceeds. A provisional correlation of temperature fields to component porosity assessed by 3D computed tomography demonstrates in situ optical detection of micron-scale porous defects in LPBF.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
