双相TiAl合金脉冲电化学加工多尺度多目标优化策略研究

TiAl合金在航空发动机低压涡轮叶片上的成功应用，提高了研究者们对TiAl合金无损加工的研究兴趣，实现高精度、高表面质量的双相TiAl合金的稳定电化学加工是值得密切关注的问题。项目采用Monte Carlo与分形理论建立粗糙表面BDM双电层模型，弄清双相Ti-48Al-2Cr-2Nb合金/溶液界面结构演变机理；分析脉冲电化学加工系统的电流分岔特性、产生机理及影响机制，建立电流与控制参量的分岔模型；利用非线性等效电路模型建立加工系统数学模型；利用反应-扩散分形生长模型重构表面微观形貌演变机理；建立各向异性材料模型与多相多场耦合仿真模型，分析微米尺度下的物质去除机理与微观形貌演变规律；利用多场耦合细观模型分析电流密度、加工间隙等的分布规律；从纳米、微米、细观三尺度建立目标函数，采用微分进化算法实现工艺优化，为TiAl合金叶盘的脉冲电化学加工提供理论基础。

The successful application of TiAl alloys to low-pressure turbine blades of aeroengines has increased researchers' interest in non-destructive machining of TiAl alloys. The realization of stable electrochemical machining of high-precision and high-surface quality in two-phase TiAl alloys is a matter worthy of close attention. A rough surface BDM electric double layer model will be built by Monte Carlo and fractal theory and to illuminate the evolution of interface structure of two-phase Ti-48Al-2Cr-2Nb alloy / solution. The characteristics, generation mechanism and influence mechanism of the current bifurcation of the pulse electrochemical machining system will be analyzed, and bifurcation models between current and control parameters will be built. In addition, a nonlinear equivalent circuit model will be established for the mathematical model of the machining system. The evolution of surface micro-topography will be reconstructed by a reaction-diffusion fractal growth model, and a mathematical model between current and surface micro-topography will be also researched. An anisotropic materials model and a multi-phase flows, multi-field simulation model will be set up to analyze the material removal mechanism and the evolution of micro-morphology in micrometer scale. At the same time, the multi-field coupled meso-model will be used to analyze the distribution laws of current density and machining gap. The objective functions will be established from the three scales of nano-scale, micro-scale, and meso-scale for the process optimization by differential evolution algorithm. The project will provide a theoretical basis for pulse electrochemical machining of TiAl alloy blade disk.