超声冲击原位辅助的超高速激光沉积非晶涂层制备及形性调控

苛刻的服役环境对工程装备安全运行提出了严峻挑战，激光表面非晶化技术是提升其服役水平的重要途径，但传统激光熔覆技术制备非晶涂层存在非晶体积含量低、断裂韧性差等不足。本项目提出采用超声冲击原位辅助的超高速激光沉积工艺制备高性能（Ni-Fe-Co）-B-Si-Nb体系非晶涂层，主要研究内容包括：研究沉积过程中微熔池动态质能传输行为对涂层组织及成形的影响规律，优化合金体系的成分比例并明确涂层的非晶形成机制；探讨超声冲击参量与涂层残余应力分布、流变单元有效浓度和剪切带萌生/扩展行为之间的非线性关联，阐明超声冲击对涂层残余应力与拉伸塑性的协同作用机制；探究局部应力状态和非晶含量等因素对涂层腐蚀与摩擦损伤演变行为的影响规律，构建涂层损伤力学模型和寿命预测模型。最终实现高非晶含量、强韧均衡非晶涂层的一体化可控制备。研究成果可为我国关键工程装备的涂层防护与延寿提供理论指导和技术支撑。

Extreme service environment puts forward severe challenge for security operation of engineering equipment. Laser amorphization process gives a good choice for an increasing service level. Low amorphous volume fraction and bad fracture toughness are the main defects in the amorphous coatings fabricated by traditional laser cladding process. In this study, fabrication of high performance (Ni-Fe-Co)-B-Si-Nb amorphous coating by ultra-high speed laser deposition with in-situ UIT assistance is developed. Firstly, the influence of material/energy transferring behavior in micro-pool during laser deposition process on microstructure and morphology formation will be investigated to optimize the element proportion and clarify the amorphous phase formation mechanism. Secondly, the non-linear relationship between UIT parameters and residual stress distribution, flow units, shear bands formation/expanding behavior will be established in order to learn the synergistic action mechanism of UIT on residual stress and tensile plasticity. Then, the influence rule of regional stress state and amorphous fraction on corrosion, wear damage evolution will be systematically investigated to build the damage mechanical model and life prediction model. At the end, an integrated controllable preparation method will be developed for a high volume fraction and strength/toughness equilibrium amorphous coating. The research results can give not only theoretical direction but also technical support for coating protection and life extension of key engineering equipment.