Thermal-induced wave propagation frequently occurs during the laser powder bed fusion (LPBF) process due to the laser-material interaction. However, the effect of thermal variation and the resulting metallurgical phase transition on the wave propagation characteristics remains unclear. This paper presents a semi-analytical modeling of thermo-metallurgical-induced wave propagation in the LPBF of titanium alloys. In this modeling, the transient temperature field related to laser motion is first predicted based on the differential quadrature method. Subsequently, the temperature and corresponding metallurgical phase transition are employed to analytically obtain the wave propagation characteristics based on the higher-order shear deformation theory. The accuracy of the proposed model is verified by the comparison with the results in the literature. In addition, the impact of process parameters, part geometries, and heat source parameters on the temperature field and wave propagation of LPBF-built titanium alloys is analyzed. The predicted results show that the temperature field increases with higher energy densities and laser penetration, while decreasing with the increased preheating temperature, length-to-width ratio, laser semi-axis, and layer thickness. The elevated temperature leads to the decreasing wave frequency and phase velocity. These results can serve as a guideline for health monitoring and defect determination during the LPBF process of titanium alloys.

中文翻译：

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激光粉末床熔合钛合金零件热冶金诱发波传播的半解析建模

由于激光与材料的相互作用，在激光粉末床熔化（LPBF）过程中经常发生热致波传播。然而，热变化和由此产生的冶金相变对波传播特性的影响仍不清楚。本文提出了钛合金 LPBF 中热冶金引起的波传播的半解析模型。在该建模中，首先基于微分求积法预测与激光运动相关的瞬态温度场。随后，基于高阶剪切变形理论，利用温度和相应的冶金相变分析获得波传播特性。通过与文献结果的比较，验证了所提模型的准确性。此外，还分析了工艺参数、零件几何形状和热源参数对LPBF构造钛合金温度场和波传播的影响。预测结果表明，温度场随着能量密度和激光穿透力的增加而增大，而随着预热温度、长宽比、激光半轴和层厚的增加而减小。温度升高导致波频率和相速度降低。这些结果可以作为钛合金LPBF过程中健康监测和缺陷判定的指南。