Daoud Mohamed E, Taha Inas, Abdelgawad Ahmed, Barsoum Imad, Khan Kamran A, Anjum Dalaver H
Department of Physics, Khalifa University, P. O. Box 127788, Abu Dhabi, United Arab Emirates.
Department of Mechanical Engineering, Khalifa University, P. O. Box 12788, Abu Dhabi, United Arab Emirates.
Sci Rep. 2025 Jul 9;15(1):24784. doi: 10.1038/s41598-025-09316-0.
Residual stresses in metal alloys fabricated by the powder bed fusion-laser beam (PBF-LB) method exhibit anisotropy influenced by laser scanning and building orientations. This study maps nanoscale residual stresses within a single grain of PBF-LB AlSi10Mg alloy using various transmission electron microscopy (TEM) modalities. Residual stress maps were obtained for both as-built and T6 heat-treated samples along scanning and building orientations. Post-analysis revealed that T6 heat treatment reduced tensile stress compared to as-built samples. For example, in the [1̅00] crystallographic direction, average tensile and compressive residual stresses in the building direction decreased by ~ 70% after T6 treatment. Anisotropy in residual stresses was also observed; in the [1̅00] direction, average residual stresses in scanning orientation were ~ 13% and ~ 23% higher than the building direction in as-built and T6-treated samples, respectively. Heat treatment effects were further examined using image-based finite element method (FEM) simulations to understand the stress-driven mechanisms behind Si eutectic break-up and Si precipitate diffusion into the Al matrix. The results revealed regions of tensile and compressive stress within Si eutectic zones, identifying them as sources for Si diffusion and nucleation of Si-based precipitates within the matrix.
通过粉末床熔融激光束(PBF-LB)方法制造的金属合金中的残余应力表现出受激光扫描和构建方向影响的各向异性。本研究使用各种透射电子显微镜(TEM)方法绘制了PBF-LB AlSi10Mg合金单个晶粒内的纳米级残余应力。沿着扫描和构建方向获得了原始态和T6热处理样品的残余应力图。分析后发现,与原始态样品相比,T6热处理降低了拉伸应力。例如,在[1̅00]晶体学方向上, T6处理后构建方向上的平均拉伸和压缩残余应力降低了约70%。还观察到残余应力的各向异性;在[1̅00]方向上,原始态和T6处理样品中扫描方向的平均残余应力分别比构建方向高约13%和23%。使用基于图像的有限元方法(FEM)模拟进一步研究了热处理效果,以了解Si共晶分解和Si析出物扩散到Al基体背后的应力驱动机制。结果揭示了Si共晶区内的拉伸和压缩应力区域,将它们确定为Si扩散和基体中Si基析出物成核的来源。