基于CA-LB多场耦合的钛合金激光快速成形熔池凝固枝晶生长机理研究

项目名称： 基于CA-LB多场耦合的钛合金激光快速成形熔池凝固枝晶生长机理研究

项目编号： No.51205261

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 王志坚

作者单位： 沈阳航空航天大学

项目金额： 25万元

中文摘要： 钛合金广泛应用于航空航天等领域，钛合金激光快速成形技术具有省材、节时、低成本、柔性程度高和加工零件综合性能优异等特点，成为近年来钛合金制造技术发展的总趋势。目前钛合金激光快速成形凝固微观晶粒形态和缺陷形成机理仍处在实验摸索阶段，缺少描述凝固过程多场耦合的理论模型和对微观组织的正确预测，致使成形零件质量和综合力学性能难以实现精确控制。本课题以Ti-6Al-4V钛合金为熔覆材料，采用元胞自动机法和格子Boltzmann法耦合，建立熔池凝固流场、温度场、溶质浓度场和枝晶生长等多场耦合数学模型，运用理论、模拟和实验相结合的方法，从微观尺度研究熔池凝固动态演化特性，揭示熔池内钛合金凝固枝晶形貌和缺陷形成机理，阐明激光功率、扫描速度、离焦量和送粉量等宏观工艺参数对微观组织形态的作用机制，从而实现正确预测和控制成形过程、优化组织、抑制缺陷的目的，为优化激光工艺参数、提高成形零件质量提供理论依据。

中文关键词： 钛合金；激光快速成形；元胞自动机法；多场耦合；微观晶粒

英文摘要： Titanium alloy is widely used on the aerospace and some other fields. The laser rapid forming of titanium alloy has the advantages of saving material and time, low cost, high flexibility and excellent combination properties of components and has recently been the chief tendency of titanium alloy fabrication technique. Currently the formation mechanisms of micro-grain morphology and microdefect during the solidification of titanium alloy laser rapid forming are still on the stage of exploratory experiments. Lacks of exact multi-field coupling theoretical model and prediction of microstructure during laser molten pool solidification make it difficult to precisely control the quality and combination mechanical properties of components. Ti-6Al-4V titanium alloy is used as the cladding material and the cellular automaton method and Lattice Boltzmann method are coupled to build the multi-field coulping mathmatical models of flow, temperature, solute concentration and dendritic growth fields during molten pool solidification. The characteristics of solidifation dynamic evolution are studied in laser molten pool from microscale and the dendritic morphology of titanium alloy and formation mechanism of microdefect are explored by the method of combining theoretical model, simulation with experiments. The influence mechani

英文关键词： Titanium alloys；Laser rapid forming；Cellular automata method；Multi-field coulping；Microstructure morphology