Abstract The Direct Laser Deposition (DLD) process has shown significant results in manufacturing due to its relevant flexibility to refurbish high-performance components (e.g. turbine blades or disks) or fabricating complex shaped parts. The solidification microstructure during the DLD process, is known to be controllable using different process parameters that induce changes in the grain structure, micro-segregation, and phase transformations. This work focuses on the effect the frequency of the pulsed laser has on the metallurgical characteristics of deposited thin walls. More specifically, the effect of three different pulsing rates (10 Hz, 100 Hz, 1000 Hz) during the deposition of the Nickel-based superalloys Inconel 718 has been studied and the results compared with parts produced by continuous wave laser mode. This work highlights how the pulsing rate significantly affected the thermal history, melt pool shape, grain size and its morphology, segregation region (Nb-enriched), and hardness. Finally, the microhardness was also evaluated and a correlation between the metallurgical characteristics and the pulsing rate was established.

中文翻译：

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激光源脉冲频率对直接激光沉积Inconel 718薄壁的影响

摘要 直接激光沉积 (DLD) 工艺因其在翻新高性能部件（例如涡轮叶片或圆盘）或制造复杂形状零件方面的相关灵活性而在制造中显示出显着的效果。众所周知，DLD 过程中的凝固微观结构可以使用不同的工艺参数进行控制，这些参数会引起晶粒结构、微观偏析和相变的变化。这项工作的重点是脉冲激光的频率对沉积薄壁的冶金特性的影响。更具体地说，研究了镍基高温合金 Inconel 718 沉积过程中三种不同脉冲频率（10 Hz、100 Hz、1000 Hz）的影响，并将结果与​​连续波激光模式生产的部件进行了比较。这项工作强调了脉冲速率如何显着影响热历史、熔池形状、晶粒尺寸及其形态、偏析区域（Nb 富集）和硬度。最后，还评估了显微硬度，并建立了冶金特性与脉动率之间的相关性。