电脉冲作用下Al-Cu合金铸造织构转变机理及其对耐蚀性影响的研究

The theories of texture control for solid alloy have trended to be mature, however, it relatively lags for the studies of as-cast texture produced during liquid-solid phase transformation, and these studies focus mainly on the conditions of temperature and stress control, few works involve the electromagnetic field. It is of significant importance for digging into the performance potential by bring forward the texture control to the solidification duration and even the stage of metal melt. In this project, the Al-Cu binary alloys are treated by pulse electromagnetic field at different metallurgical phases, the evolution characteristics and control technology of the as-cast textures in this case are explored; Furthermore,based on the theory of liquid metal structure and the simulation calculation of thermal-electromagnetic field coupling, combining with the tests of micro-area texture and the analysis of grain boundry distribution configuration, the crystal growth rules are investigated under that non-equilibrium solidification condition, and hereby the changing mechanism of as-cast texture and the electropulse control rule are both built. On the other hand, this project regards the electrochemical property of an alloy as breakthrough point differentiated with the previous idea of focusing on the mechanical properties of an alloy, and discusses the relationship between the texture changes and the corrosion resistance of Electropulse-treated Al-Cu alloy. On this basis, the novel theoretical foundation and practical technique will be proposed how to control the texture configuration from metallurgical initial phase and then improve the material performance.

固相合金的织构控制理论已逐渐走向成熟，但对合金液固相变所形成的铸造织构研究却相对滞后，而且集中于温度和应力等控制条件，较少涉及到电磁场。将织构调控提前至合金凝固期间甚至是冶金熔体阶段对于充分挖掘材料性能潜力具有重要意义。本项目在金属熔体阶段对纯铝和铝铜二元合金施加电脉冲，探索该条件下铸造织构的转变规律及其控制技术；基于液态金属结构理论，结合微区织构测试及晶界分布组态分析，建立这种非平衡凝固条件下晶体生长模型，提出铸造织构的转变机理及电脉冲调控规律。以合金电化学性能为切入点，研究铸造织构转变对金属耐蚀性影响的实验规律。本项目旨在从冶金源头控制合金织构组态，进而改善材料使用性能，为生产应用提供理论基础与实用手段。

电脉冲对晶体生长影响的机制尚不明确。本项目在金属熔体阶段对纯铝和铝铜二元合金施加电脉冲，探索了该条件下由晶体生长所形成铸造织构的转变规律及其控制技术；基于液态金属结构理论，建立了这种非平衡凝固条件下的晶体生长模型，提出了铸造织构的转变机理及电脉冲调控规律。以耐蚀性能为切入点，研究了铸造织构转变对金属耐蚀性影响的实验规律。本项目旨在从冶金源头控制晶体生长及其织构组态，进而改善材料使用性能，为生产应用提供理论基础与实用手段。