Modeling of temperature distribution and clad geometry of the molten pool during laser cladding of TiAlSi alloys
Modeling of temperature distribution and clad geometry of the molten pool during laser cladding of TiAlSi alloys
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DOI：
10.1016/j.optlastec.2021.107277
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发表时间：
2021-10
影响因子：
5
通讯作者：
Chen Shen;Chonggui Li;Yajun Guo;Chuanming Liu;Xuanjun Zhang;Xiao-song Feng
中科院分区：
文献类型：
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作者：
Chen Shen;Chonggui Li;Yajun Guo;Chuanming Liu;Xuanjun Zhang;Xiao-song Feng
激光熔覆过程中熔池的温度变化规律对熔覆层的截面尺寸至关重要，从而影响熔覆层的性能。在这项研究中，一个修改后的三维（3D）瞬态有限元模型，模拟温度的演变和熔覆TiAlSi涂层的熔池的几何形状。通过理论计算，区分了TiAlSi粉末和TiAlSi合金的热性能差异，提高了模拟结果的精度。建立了高斯体热源模型。利用温度选择判断机制，比较元素的平均温度和材料的熔点，以区分粉末和合金元素。采用能量沿穿透方向沿着呈指数分布的衰减规律来模拟激光束被粉末颗粒和颗粒间空隙所偏转的情况，对高斯热源进行修正。研究了不同激光功率和扫描速度对熔覆层形貌的影响。利用多项式拟合曲线对仿真计算的轨道深度和宽度进行了分析。结果表明，激光功率与扫描速度成反比，而激光功率与扫描速度成正比。通过多项式拟合方程可以计算任意激光功率（600-1800 W）和扫描速度（0.005-0.025 m/s）下熔覆层的几何尺寸。扫描速度对轨迹深度的影响更大。将仿真结果与试验测量得到的履带宽度和纵向截面尺寸进行匹配，验证了模型的正确性。修正后的三维瞬态有限元模型能够描述单道激光熔覆的几何形状。
The temperature varying principal of the molten pool is crucial to coatings’ cross-section sizes during laser cladding process, which can influence the performance of the coatings. In this study, a modified three-dimensional (3D) transient finite element model was presented to simulate the temperature evolution and clad geometry of the molten pool of TiAlSi coatings. The difference of thermal properties in TiAlSi powders and TiAlSi alloys were distinguished to improve the precision of simulation results through theoretical calculation. The Gaussian body heat source model was established. A temperature selection judgment mechanism was utilized to compare the average temperature of the element and the melting point of the material to distinguish powder and alloy elements. An exponential distribution of energy attenuation along penetration direction was employed to simulate the laser beam deflected by the powder particles and the void among the particles to correct Gaussian heat source. The effect of different laser power and scan speeds on the cladding layer morphologies were investigated. The track depth and width calculated by simulation were analyzed by polynomial fitting curves. The results showed that the track depth and width were directly proportional to laser power, whereas inversely to scanning speed. Geometric dimensions of cladding layers at arbitrary laser power (600–1800 W) and scan speed (0.005–0.025 m/s) can be computed by polynomial fitting equation. Track depth was more impressed by scanning speed. The track width and longitudinal size of cross-section geometry from the simulation results and experiment measurement were matched to validate the presented model. The modified 3D transient finite element model is able to describe the geometry of single-track laser cladding.