基于分形表征的堆焊再制造层界面生长机理及性能研究

Surfacing deposition forming is one of key surpport technologies to remanufacturing. But it exists heterogeneity interface problem between surfacing remanufactured layer and the remanufacing matrix, as the material reason.Interface is one of third choke points to remanufacturing,and its effect on remanufacturing quality is prominent. So, the forming mechanism of the bonding interface between surfacing deposition layer and the remanufacing matrix, even its effect on the property of the surfacing remanufactured layer will be researched, preconditioned that the bonding interface configuration is denoted quantitatively with fractal dimension, in this requisition. First, remanufacturing matrix surface configuration, bonding interface configuration between surfacing remanufactured layer and the remanufacing matrix are denoted quantitatively with fractal dimension. Then, remanufacing matrix surface fractal model is designed, and the growthing course is modeled and pursued to research its forming mechanism,based on the designed fractal surface model.Even the effect factors and them’s effect on bonding interface forming are searched and studied. At last, the relationship among the surfacing remanufactured layer’s property, fractal dimension of remanufacturing matrix, process parameters fractal dimension of bonding interface and other facters are exploited, and bonding interface’s effect on property of the remanufactured layer is determined. Based on the research in this project,the forming mechanism of the bonding interface can be clear, and the forecast mathematic model of the property of surfacing remanufactured layer is build, so that the remanufactured piece is avoid to be breached to exploit the layer’s property of. Even that this research in this project can be taken as technic support to the design and controlling on the surfacing deposition forming remanufacturing layer’s property, and the development and application of surfacing deposition forming remanufacturing technology can be promoted finally.

堆焊熔敷成形技术是再制造关键支撑技术之一。但由于材料原因，堆焊再制造层与基体之间往往存在异质界面问题，界面是再制造的三大瓶颈之一，对再制造质量有非常重要的影响。因此，本申请拟进行基于分形表征的堆焊再制造层结合界面生长机理，以及结合界面对再制造层性能的影响研究：首先，利用分维实现对再制造层结合界面形貌、基体表面形貌的准确定量表征；然后，设计基体表面分形模型，进行基于分形特性粗糙面的结合界面生长形成过程模拟追踪研究，结合实验观测分析，揭示结合界面生长形成机理，并分析各影响因素对其生长行为的影响；最后，研究再制造层性能与结合界面分维、工艺参数等因素之间的量化关系，确立结合界面对再制造性能的影响。通过项目研究，弄清堆焊再制造层结合界面生长形成机理，建立再制造层性能反推预测模型，可以避免进行材料的破坏性实验，进而为实现堆焊再制造层性能的设计与控制提供技术支撑，推动堆焊熔敷成形再制造技术的发展与应用。

针对再制造覆层与基体间异质界面是再制造瓶颈问题和FV520B不锈钢国内再制造研究基础薄弱问题，本项目引入分形理论，主要进行了包括成形层表面、成形层与基体结合界面以及成形层微观组织结构等在内的FV520B不锈钢MAG堆焊再制造成形层定量化表征、再制造成形层表界面行为研究，再制造成形层组织性能，以及振动、热处理对其影响的研究。研究表明：基于分维数可以实现FV520B不锈钢MAG堆焊再制造成形层的分形定量化表征，再制造成形过程中不断生成的焊缝熔池与基体间熔合面相互作用、搭接形成的成形层与基体的熔合面即为再制造成形层与基体间结合界面，随再制造成形过程的不断进行，结合界面复杂性及其分维数呈不断增大趋势，再制造成形层的分形特性是由其成形技术原理的分形特性遗传决定的—增材制造技术 “由点成线，由线成面，由面成体”的微积分成形制造原理具有自相似分形特性，这为增材制造/再制造成形研究提供了新视角和新的技术方法。. FV520B不锈钢MAG堆焊再制造成形层由马氏体+NbC，MoC，M23C6等碳化物沉淀硬化相组成。受振动的影响，马氏体板条宽度，各晶面Bragg衍射峰峰位角、晶格畸变程度以及晶面择优取向性都会发生变化；亚共振频率（f=3000r/min）振动对再制造成形层晶粒细化、减轻晶格畸变作用以及材料各向异性增强作用最显著。热处理可以削弱再制造成形层晶格畸变、弱化（110）晶面择优取向性；660℃+4h保温是较理想热处理工艺，可同时起到消除成形层与基体间结合界面，细化晶粒，削弱晶格畸变及材料各项异性作用。 . FV520B不锈钢MAG堆焊再制造成形层具有高强度、高硬度特性和优异摩擦学性能，抗拉强度达为1195MPa，超过基材，屈服强度、硬度和干摩擦学性能与基材相当，但冲击韧性相对较低；亚共振频率振动（f=1500r/min）对再制造成形层静拉伸力学性能和摩擦学性能提升作用最明显，此条件下其抗拉强度和屈服强度分别可达1300 MPa和839.4MPa，但振动对硬度作用不明显且会降低其冲击韧性。振动和热处理对再制造成形层组织性能的影响研究可为再制造强化处理提供技术参考和指导。