双电弧冷金属过渡高效增材制造工艺与机理研究

The proposed double wire cold metal transfer aims at solving problems such as excessive heat input and poor molding precision during additive manufacturing of aluminum alloy, stainless steel, and nickel-base alloy.. Combined with numerical simulation and experiments, the interaction between double arc, the mechanism of metal transfer, and stability of metal transfer during double wire cold metal transfer additive manufacturing are studied. The prediction models of solidification structure and mechanical properties are established based on the heat transfer and fluid flow model. Using synergistic control of integrated power supply, which controlled amplitude and frequency of CMT wire feeding and trapezoid wave or sine wave modulated double-pulsed current waveform, the support vector machine model and fuzzy control algorithm are setted up for welding current, welding speed, wire feeding rate and deposition layer dimension, and the process optimization of additive manufacturing is achieved.. The prime novelty of the project include：Combined the control technology of cold metal transfer by using new modulated double-pulse with high speed, high efficiency and double arc manufacturing, the heat input is reduced and the deposited efficiency of arc additive manufacturing is increased; Combined a customized wire-feeding machine, which is made in China with an integrated double arc welding power supply, which a single DSP is built-in, the control technology of different waveforms is realized flexibly by autonomous programming.. The research results of the project would provide a theoretical basis for probing the process mechanism of double arc cold metal transfer, high efficiency manufacturing, and also provide newly scientific methods and support for large metallic components with perfect structure and excellent performance.

项目采用双电弧冷金属过渡方法解决铝合金、不锈钢和和镍基合金增材制造中存在的热输入过高和成型精度低等问题。利用数值模拟和工艺试验相结合研究双丝冷金属过渡的双电弧相互作用及金属熔滴过渡机理和稳定性，并基于热传递与液体流动模型建立凝固组织和机械性能预测模型。利用一体化电源对送进回抽送丝幅度、频率与梯形波或正弦波调制双脉冲焊接电流波形的协同控制，建立焊接电流、焊接速度和送丝速度与沉积层尺寸的支持向量机模型及模糊控制算法，实现增材制造的工艺优化。项目创新地将新型双脉冲调制的冷金属过渡控制技术和高速高效双电弧增材制造相结合，降低电弧增材的热输入和提高其熔敷效率；采用定制国产振康回抽型送丝机，与内置DSP的一体化双丝电源结合，通过自主编程灵活实现不同波形的控制技术。项目研究成果可为透视双电弧冷金属过渡高效增材制造的工艺机理提供理论基础，为获得结构健全及性能优异的大型金属构件提供新的科学方法和手段。

课题组在国家自然科学基金的资助下，经过4年的研究工作，严格按照申请书制订的研究工作计划进度开展课题的攻关，通过对单丝铝合金单双脉冲电弧增材制造熔池的温度场和流速场仿真，阐述沉积过程晶粒细化的机理；通过对单丝和双丝电弧增材制造不锈钢薄壁件的研究，为双电弧冷金属过渡高效增材制造的工艺机理提供理论基础、并对工艺参数进行了优化；在基于CMT+P模式下，研究不同焊接线能量输入，对于焊缝成型质量的影响；对双脉冲气体保护焊的电流波形进行改进，提出了一种低热输入双脉冲气体保护焊；探索了双丝等离子弧添加剂制造技术，制备了不同成分梯度的316L/Inconel625功能梯度材料；拓展研究了三丝等离子弧增材制造高熵合金制备工艺，并研究了不同Al含量的合金组织及其性能的演变。课题研究成果发表论文36篇，其中SCI收录20篇（其中第一作者1篇，通讯作者15篇），EI收录9篇（其中第一作者4篇，通讯作者4篇）,中文核心2篇(第一作者2篇)；提交博士学位论文7篇，硕士学位论文11篇。申请受理发明专利10件，授权发明专利3件。参加国际学术交流会议9次，共做汇报7次，其中特邀报告2次。