在本文中，通過雷射金屬箔材列印技術 (LFP) 成功製造出無裂痕6061鋁合金件。並根據雷射作用時間 (TL) 以及線能量密度 (LED) 對製程參數進行優化。在700 W的雷射功率下進行單道實驗，以研究掃描速度對熔池形成的影響。當掃描速度達到130 mm/s時，裂紋形成。EBSD圖像顯示，由於熱輸入量減少，熔池邊界的晶粒尺寸減小。當掃描速度低於100 mm/s時，由於輸入能量較高，熔池截面會出現氣孔以及熔池凹陷的缺陷。後續使用700 W雷射功率以及100 mm/s掃描速度的優化參數進行多層零件。四個LFP零件拉伸試樣的平均極限拉伸強度 (UTS) 為246 MPa，平均伸長率為8%。斷裂面顯示出韌性斷裂特有的破裂面、滑移面、微孔洞以及分離的柱狀晶粒。並根據XRD和EBSD的結果證明 (200) 峰值代表柱狀晶粒的存在。
除此之外，本文也研究預熱處理於6061鋁合金樣品上晶粒和表面波紋結構的演變，以瞭解預熱如何影響微觀結構。為評估預熱溫度對於熔池形成的影響，文中建立了一個三維有限元素模型。模擬結果表明，隨著預熱溫度的升高，凝固速率降低，導致冷卻時間延長。EBSD結果顯示了晶粒大小的變化，當預熱溫度低於450˚C時，平均晶粒大小由75.6 μm增加至136.8 μm。同時，(001) 取向強度的增加顯示柱狀晶粒生長的特徵。然而，當樣品預熱溫度高於450˚C時，平均晶粒大小減小至105.7 μm，(111) 取向的出現指出在加工過程中發生了再結晶。此外，凝固速率的降低延長了冷卻時間，導致表面粗糙度 (Sa) 從21.7 μm降至5.2 μm，熔池表面上的波紋也隨著預熱溫度的升高而減少。XRD結果進一步證實了柱狀晶粒的增加和再結晶的存在，與EBSD結果相符。

In this study, crack-free aluminum alloy 6061 parts were successfully fabricated using the laser foil printing (LFP) process. Parametric optimization of the processing map was conducted based on laser interaction time (TL) and line energy density (LED). Single-track experiments were performed at a laser power of 700 W to investigate the influence of scanning speed. Cracks formed when the scanning speed reached 130 mm/s. Electron backscattered diffraction (EBSD) patterns indicated a reduction in grain size along the melt pool boundary due to a decrease in heat input. At scanning speeds below 100 mm/s, pores and cavities emerged due to the high energy input. Subsequently, multilayer parts were fabricated using the optimized parameters of 700 W laser power and a scanning speed of 100 mm/s. Four tensile specimens of the LFP parts exhibited an average ultimate tensile stress of 246 MPa and an elongation of 8%. The fracture surfaces revealed dimples, cleavages, slip regimes, and disbanded columnar grains characteristic of ductile fracture. X-ray diffraction (XRD) and EBSD results indicated the presence of columnar grains with a (200) peak.
The evolution of the grain and ripple structures on the preheated AA6061 samples was also investigated to understand how preheating affects the microstructure. A three-dimensional FEM model was constructed to assess the effects of preheating temperature. Simulation results indicate that as the preheating temperature increases, the solidification rate decreases, leading to an increase in cooling time. The EBSD results reveal an evolution of average grain size, which increases from 75.6 μm to 136.8 μm when the preheating temperature is below 450˚C. The concomitant increase in the (001) orientation is characteristic of columnar grain growth. However, when the sample is preheated above 450˚C, the average grain size decreases to 105.7 μm, and the appearance of the (111) orientation indicate that recrystallization occurred during processing. The reduction in the solidification rate increases the cooling time, leading to an improvement in surface roughness (Sa) from 21.7 μm to 5.2 μm. Ripples on melt pool surface were also found to be reduced with increasing preheating temperature. XRD results further confirm the increased columnar grains and the presence of recrystallization, aligning with the EBSD results.

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