基板预热温度对激光金属沉积成形零件微观组织的影响

Effects of substrate preheating temperature on microstructures of parts formed by laser metal deposition shaping

基板预热可以显著降低激光金属沉积成形(laser metal deposition shaping,LMDS)过程的热应力,从而抑制成形过程裂缝的产生,但基板预热温度的高低对成形零件的微观组织有着重要的影响,因此研究不同基板预热温度下激光金属沉积成形零件的微观组织变化规律对基板预热温度的选择具有非常重要的意义.利用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,采用Ni60A金属粉末在基板未预热和预热到200,300,400,500和600℃时分别进行成形试验.然后利用扫描电子显微镜和能量散射谱仪对成形试件的微观组织进行深入的研究,得到不同基板预热温度对激光金属沉积成形零件微观组织的影响规律,为基板预热温度的优化选择提供了重要参考.

Substrate preheating could significantly decrease the thermal stress during LMDS processing, and thereby inhibiting the generation of cracks. However, the level of substrate preheating temperature had an important impact on the microstructures of the forming parts, and it was of great importance for the choice of substrate preheating temperature to understand the effects of substrate preheating temperature on microstructures. Through the LMDS system and substrate preheating system constructed and developed successfully by Shenyang Institute of Automation, Chinese Academy of Sciences, LMDS experiments without substrate preheating or under the preheating temperature of 200, 300, 400, 500, 600℃ were carried out with Ni60A separately. By using scanning electron microscopy and energy scattering spectrometer, deep research on microstructures of the shaped parts were carried out. The regularities of the effects of different substrate preheating temperature on the microstructures of those parts formed by LMDS are obtained, and they can provide the important references for optimization and choice of substrate preheating temperature.