搅拌摩擦增材制造的微观结构-力学性能一体化数值模拟

Integrated Modelling of Microstructure and Mechanical Property in Friction Stir Additive Manufacturing

搅拌摩擦增材制造技术是在搅拌摩擦焊接的基础上发展起来的一种新型固态增材制造技术。针对搅拌摩擦增材制造技术中的重新搅拌和重新加热问题,采用试验和数据方法进行分析,通过Monte Carlo模型计算微观结构演化,通过析出相演化模型计算析出相分布,并进一步计算不同增材层之间的硬度分布,通过与试验测量数据的比较验证了模型的正确性。结果显示,不同增材层之间的晶粒大小和形貌由于重搅拌和重加热的作用而存在差异,同时,温度曲线的变化使粒子数和平均半径发生变化,进而导致力学性能出现差异。在试验验证的基础上,通过数值模拟解释了差异产生的具体机理。

As a new solid state additive manufacturing technology,friction stir additive manufacturing is developed based on friction stir welding.For the re-stirring and re-heating phenomena in friction stir additive manufacturing,both experimental and numerical methods are used for analysis.Monte Carlo method is used to calculate the microstructural evolutions.The precipitate distributions are calculated by the developed precipitate evolution model.The hardness distributions on different additive manufactured layers are then calculated.Experimental data is compared to show the validities of the numerical models.Results indicate that different grain sizes and morphologies can be found due to the existences of restirring and re-heating.The variations of particle numbers and mean radii of precipitates on different layers,caused by different temperature histories,can lead to the different mechanical properties.The mechanism for the generation of different mechanical properties in different layers are explained by numerical simulations in combination with experimental validation.