氧化铝陶瓷材料激光选区熔化成形过程模拟与实验研究

发布时间：2018-01-29 23:12

本文关键词： 激光选区熔化氧化铝温度场应力场熔化程度扫描策略预热温度　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：陶瓷材料具有耐高温、耐腐蚀、耐磨损、高强度、高硬度、抗氧化等诸多优点,近年来在航空航天、生物医疗、汽车、建筑领域内的应用日益广泛。然而,陶瓷材料固有的高强度、高硬度、高脆性等特性给传统加工工艺带来了挑战,尤其对于形状复杂的陶瓷件,通常需要借助于复杂的模具实现,生产周期长,制造成本高,某种程度上限制了陶瓷材料的应用和发展。激光选区熔化技术(Selective Laser Melting,SLM)熔融成形、无需模具、适用材料种类多的技术优越性为复杂陶瓷构件的快速制造提供了新的思路。开展陶瓷材料SLM成形工艺的研究,不仅可以丰富成形陶瓷的工艺手段,而且能够显著缩短陶瓷零件的生产流程,提高成形件性能。本文主要开展氧化铝陶瓷材料激光选区熔化成形过程模拟与实验分析研究,基于仿真分析和工艺实验,研究关键工艺参数对陶瓷材料SLM成形效果的影响。主要研究工作包括如下四点:(1)研究了 SLM有限元分析理论以及仿真模型构建方法,基于温度场、应力场有限元分析理论,设定了热源函数和边界条件,实现了材料性能非线性处理以及相变潜热处理,建立了陶瓷材料有限元分析模型;(2)研究了氧化铝陶瓷材料SLM成形温度场仿真分析方法,通过研究熔池尺寸、温度梯度分布、液相时间、升温速率分析了激光扫描速度、激光功率、扫描策略和预热温度对温度场分布的影响;(3)研究了氧化铝陶瓷材料SLM成形应力场仿真分析方法,基于间接热应力耦合法实现了氧化铝应力场模型的构建,探索了成形过程中的应力场分布规律,分析了激光扫描策略和预热温度对应力场分布的影响;(4)开展了氧化铝陶瓷材料SLM成形工艺实验,研究了不同氧化铝粉末状态对应的铺粉质量差异,分析了扫描速度、激光功率、扫描策略对氧化铝陶瓷材料熔化程度的影响,探索了预热温度对成形效果的影响规律,验证了仿真结果的有效性。
[Abstract]:Ceramic materials have many advantages, such as high temperature resistance, corrosion resistance, wear resistance, high strength, high hardness, oxidation resistance and so on. In recent years, ceramic materials have been widely used in aerospace, biomedical, automobile and construction fields. The inherent characteristics of ceramic materials such as high strength, high hardness and high brittleness have brought challenges to the traditional processing technology, especially for ceramic parts with complex shapes, which usually need to be realized by means of complex dies, and the production cycle is long. The high manufacturing cost limits the application and development of ceramic materials to some extent. Laser selective Laser melting (SLM) melt forming. The advantages of many kinds of suitable materials provide a new idea for rapid manufacturing of complex ceramic components. The research on SLM forming process of ceramic materials is carried out. It can not only enrich the process of forming ceramics, but also shorten the production process of ceramic parts. In this paper, the simulation and experimental analysis of laser selective melting forming process of alumina ceramic material are carried out, based on simulation analysis and process experiment. The main research work includes the following four points: 1) the theory of SLM finite element analysis and the method of constructing simulation model are studied. Based on the theory of finite element analysis of temperature field and stress field, the heat source function and boundary condition are set up, the nonlinear treatment of material performance and latent heat treatment of phase change are realized, and the finite element analysis model of ceramic material is established. The simulation analysis method of temperature field of alumina ceramic material SLM was studied. The laser scanning speed and laser power were analyzed by studying the size of molten pool, temperature gradient distribution, liquid phase time and heating rate. The influence of scanning strategy and preheating temperature on temperature field distribution; The simulation analysis method of SLM forming stress field of alumina ceramic material is studied. Based on the indirect thermal stress coupling method, the stress field model of alumina is constructed, and the distribution law of the stress field in the forming process is explored. The effects of laser scanning strategy and preheating temperature on force field distribution are analyzed. (4) the SLM forming process experiment of alumina ceramic material was carried out, the quality difference of different alumina powder state was studied, the scanning speed and laser power were analyzed. The effect of scanning strategy on the melting degree of alumina ceramic material was studied. The effect of preheating temperature on the forming effect was explored and the validity of the simulation results was verified.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ174.6

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