不同基板预热温度对激光金属沉积成形过程温度场的影响

为降低成形过程的热应力，抑制成形过程裂缝的产生，减小成形过程试样和基板的翘曲变形，激光金属沉积成形往往需要进行基板预热，因此研究不同基板预热温度对激光金属沉积成形过程温度场的影响具有非常重要的意义．根据有限元分析中的“单元生死”技术，利用APDL编程建立了基板预热对激光金属沉积成形过程温度场影响的三维多道多层数值模拟模型，详细分析了基板未预热和分别预热到200，300，400，500，600 ℃时对沉积成形过程温度场和温度梯度的影响．通过中国科学院沈阳自动化研究所自行研制的激光金属沉积成形系统和基板预热系统，在与模拟过程相同的参数下，利用镍基合金粉末在基板未预热和分别预热到300，400，500，560 ℃时进行了成形试验，试验结果跟数值模拟结果吻合较好．

Effects of different substrate preheating temperature on temperature field during laser metal deposition shaping

To decrease thermal stress， restrain generation of cracks and reduce shape distortion of samples and substrate， preheating of substrate is usually required during laser metal deposition shaping (LMDS). Therefore， research on the effect of different substrate preheating temperatures on temperature field during processing is of great importance. Based on the “element life and death” theory of FEA， a 3D multi track and multi-layer model for LMDS is developed with ANSYS parametric design language (APDL). Then， effects of substrate preheating temperature on temperature field and temperature gradient are analyzed with details by setting the substrate preheating temperature at room temperature， 200， 300， 400， 500 and 600 ℃. Through LMDS system and substrate preheating system developed by Shenyang Institute of Automation， Chinese Academy of Science， and with the same parameters of simulating process， LMDS experiments are carried out with nickel-based super-alloy at room temperature, 300， 400, 500, 560 ℃. The results show good agreement with the numeric simulation. 