Abstract Laser heating is often used to perform the surface treatment by modifying local microstructural and mechanical properties of components having complex geometries. In this study, the laser surface heat treatment of a rotating cylindrical work-piece was investigated using both experimental and numerical modeling approaches, with an aim to correlate and predict the temperature distribution during the process. The depth of the laser affected zone was predicted by solving the transient heat transfer with a moving laser heat source, using finite element analysis. The temperatures derived from the microstructural examination of the experimental specimen were found to closely agree with the predicted results from the numerical simulations. The numerical and experimental results have also led to a new observation, indicating a linear variation of the absorptivity with the laser scan speed. The prediction of the cooling curves from simulation suggested the β → α ʺ phase transformation and the recovery of the β phase, and the existence of new phases were confirmed through electron microscopy. The rapid cooling during the laser surface treatment was found to induce a flake-structure that consisted of both martensite ( α ʺ ) and regained bcc ( β ) phase. A new polynomial input power function has been proposed to achieve uniform distribution of the heat penetration along the cylinder axis, saving about 10% of the material wastage.

中文翻译：

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一种控制和优化材料激光表面热处理的新方法

摘要 激光加热通常用于通过改变具有复杂几何形状的部件的局部微观结构和机械性能来进行表面处理。在这项研究中，使用实验和数值建模方法研究了旋转圆柱形工件的激光表面热处理，目的是关联和预测过程中的温度分布。激光影响区的深度是通过使用有限元分析解决移动激光热源的瞬态热传递来预测的。发现从实验样品的微观结构检查得出的温度与数值模拟的预测结果非常一致。数值和实验结果也导致了新的观察，表明吸收率随激光扫描速度的线性变化。模拟的冷却曲线预测表明 β → α ʺ 相变和 β 相恢复，并且通过电子显微镜证实了新相的存在。发现激光表面处理过程中的快速冷却会诱发片状结构，该结构由马氏体 (α ʺ ) 和恢复的 bcc ( β ) 相组成。提出了一种新的多项式输入功率函数，以实现沿圆柱轴的热穿透均匀分布，节省约 10% 的材料浪费。并且通过电子显微镜证实了新相的存在。发现激光表面处理过程中的快速冷却诱导了片状结构，该结构由马氏体 ( α ʺ ) 和恢复的 bcc ( β ) 相组成。提出了一种新的多项式输入功率函数，以实现沿圆柱轴的热穿透均匀分布，节省约 10% 的材料浪费。并且通过电子显微镜证实了新相的存在。发现激光表面处理过程中的快速冷却诱导了片状结构，该结构由马氏体 ( α ʺ ) 和恢复的 bcc ( β ) 相组成。提出了一种新的多项式输入功率函数，以实现沿圆柱轴的热穿透均匀分布，节省约 10% 的材料浪费。