The depth homogeneity of laser-treated zones is one possible factor to define the quality and efficacy of altered mechanical properties in materials. For instance, half-rounded cross-sectional shapes of laser hardened zones using Gaussian beams provide dissimilar hardened depth in the edges and center of the treated area. This means that the in-depth distribution of compressive residual stress varies between the edges and the center of the hardened area. Nonhomogeneity of compressive residual stress distributions can inhibit fatigue properties and can lead to product failure. The utilization of oscillated laser beams has been proven to improve the welding efficiency and energy input distribution to the material, which promises achieving a homogeneous depth of laser-treated zones in hardening applications. Therefore, this work examines the influence of triangular, square, and circular beam oscillation strategies on the energy input distribution during the process and the geometry of the laser-treated zones on microalloyed steel. Laser beam pathways were assembled using a vector graphic editor to visualize the energy distribution from each oscillation strategy. Cross section images of the hardened tracks were taken and related to the thermal energy input profiles. It was revealed that each oscillation strategy demonstrates characteristic temporal and spatial thermal energy input distribution, influencing the geometry of the hardened zone. The circular oscillation strategy produced a widely constant depth in contrary to the triangular and square beam oscillation due to its characteristic energy distribution that allows homogeneous heat dissemination in the material. This confirms that the laser beam oscillation strategy can tailor the energy input distribution to optimize the processing outcome.

中文翻译：

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激光束振荡策略对微合金钢表面处理的影响

激光处理区域的深度均匀性是定义材料中改变的机械性能的质量和功效的一个可能因素。例如，使用高斯光束的激光硬化区域的半圆形横截面形状在处理区域的边缘和中心提供不同的硬化深度。这意味着压缩残余应力的深度分布在硬化区域的边缘和中心之间变化。压缩残余应力分布的不均匀性会抑制疲劳性能，并可能导致产品故障。事实证明，使用振荡激光束可以提高焊接效率和材料的能量输入分布，这有望在硬化应用中实现激光处理区域的均匀深度。所以，这项工作检查了三角形、方形和圆形光束振荡策略对过程中能量输入分布的影响以及微合金钢上激光处理区域的几何形状。使用矢量图形编辑器组装激光束路径，以可视化每个振荡策略的能量分布。拍摄了硬化轨道的横截面图像，并与热能输入曲线相关。结果表明，每个振荡策略都表现出特征性的时间和空间热能输入分布，影响硬化区的几何形状。与三角形和方形梁振荡相反，圆形振荡策略产生了广泛恒定的深度，因为其特征能量分布允许材料中均匀的热传播。这证实了激光束振荡策略可以调整能量输入分布以优化加工结果。