| 摘要: |
| 激光毛化织构广泛应用于摩擦副表面以提高其接触强度和改变摩擦性能,然而现有研究存在激光成形机理复杂、形貌可控性差等问题。 通过对所建立的二维模型进行研究,考虑反冲压力、热毛细力、表面张力对激光熔池流动的影响,分析毛化过程形貌演变规律和激光作用机理。 结果表明,当激光加热时间充足时,凹坑织构中心出现凸起,且随着脉宽的增加而增大。 中心凸起的形成归因于热毛细力,且受表面张力的影响无法形成过高的凸起。 此外,熔池加热阶段形貌主要受反冲压力影响,熔池冷却初期阶段形貌主要受表面张力的主导作用,冷却后期阶段形貌主要受热毛细力的主导作用。 在考虑反冲压力、热毛细力、表面张力对激光熔池流动等影响的基础上,建立了激光毛化织构二维数值模拟模型,为未来工程应用提供了理论依据。 |
| 关键词: 激光材料加工 激光毛化织构 形貌演变 数值模拟 熔池流动 |
| DOI：10.11933/j.issn.1007-9289.20210521003 |
| 分类号:TN249 |
| 基金项目:国家自然科学基金(51975252)和 2020 年江苏省研究生科研创新计划(KYCX20_3024)资助项目 |
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| Evolution Law and Forming Mechanism of Microtexture under Variation of Laser Pulse Duration |
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XIE Xuan1, YIN Bifeng1, CHEN Shiyue1, HUA Xijun2, ZHU Dongpo2, HAN Zhichao2, LI Jianhua2, XU Sheng1
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1.College of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013 , China;2.College of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 , China
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| Abstract: |
| Laser texturing is widely used in friction pair in order to improve the contact strength and friction performance. However, there are many problems such as complex forming mechanism and poor morphology controllability. By studying the two-dimensional model, considering the effects of recoil pressure,thermal capillary force and surface tension on the flowing of laser molten pool, the morphology evolution law and laser action mechanism of texturing process are analyzed. The results elaborated the evolution of microstructure center from dimple to bulge with the increase of pulse duration. The formation of central bulge was attributed to the thermo-capillary stress and limited by Young-Laplace stress. In addition, the surface profile of the molten pool in the heating stage was mainly affected by the recoil pressure, while the initial and later phase of molten pool cooling were respectively dominated by Young- Laplace stress and thermo-capillary stress. Considering the effects of recoil pressure, thermal capillary force and surface tension on the flowing of laser molten pool, a two-dimensional numerical simulation model of laser texturing is established, which provides a reliable theoretical basis for future engineering applications. |
| Key words: laser materials processing laser texturing morphology evolution numerical simulation melt flow |
