| Finite element method has been widely used in machinery, electronics, construction, metallurgy, aerospace and other fields. In the field of materials science, researchers, via the finite element method (FEM), can not only do detailed simulation and analyses for many process of material, such as deformation, strain hardening, fracture process,etc,but also can reflect the affection of internal and external factors on the material properties, such as reinforcement's shape and distribution, matrix - reinforcement interface state, thermal residual stress, applied load, deformation temperature, etc. At the same time, researchers can get various information of material deformation process by finite element analysis (FEA), such as the distribution of applied load, variation of elastic and plastic deformation zone and the distribution of stress and strain. Therefore, finite element simulation of materials can save development costs and predict material properties.At first,this study briefly introduced the domestic and international research background about carbon nanotubes (CNTs)/magnesium matrix composites, made a summary about the research current situation and thermal and mechanical properties of carbon nanotubes (CNTs) and CNTs/magnesium composites and described the current situation and application of finite element analysis (FEA) on materials science and engineering. What's more, based on domestic and international study of carbon nanotubes (CNTs)/magnesium matrix composites, investigated the influence of Ni-coating thickness on the thermal residual stress in AZ91D magnesium matrix composite reinforced with Ni coated carbon nanotubes (Ni-CNTs/AZ91D), and researched effects of temperature and blank holder force on warm deep-drawing performance of the AZ91D magnesium alloy.In order to explore the influence of Ni-coating thickness on the thermal residual stress in Ni-CNTs/AZ91D composite, we firstly established three-dimensional finite element model of Ni-CNTs/AZ91D composite based on experiments, and then simulated thermal residual stress distribution in Ni-CNTs/AZ91D composite at different Ni-coating thickness with heat-stress coupling analysis method for discussing the relationship between Ni-coating thickness and thermal residual stress in the composites. For the Ni-CNTs/AZ91D composite materials, the thermal residual stress achieve the minimum at the thickness of Ni-coating is 6 nm. While the thickness of Ni-coating is varying from 2nm to 6nm, the thermal residual stress is diminished with the increase of the thickness of Ni-coating. While the thickness of Ni-coating is larger than 6nm, the thermal residual stress increases with increasing of the thickness of Ni-coating. Moreover, the location of thermal residual stress's maximum moves toward the interface of Ni-coating and substrate with increasing of the thickness of Ni-coating. Based on experiments, this study simulated the forming process for AZ91D magnesium alloy sheet under different deformation temperature and blank holder force conditions by advanced explicit dynamic finite element method, and study deep-drawing performance of the CNTs/AZ91D composite under different forming temperature and different blank holder force conditions. study found that the optimum forming temperature is 250℃for AZ91D sheet.This paper explored the best Ni-coating thickness of Ni-CNTs/AZ91D composite and the optimal warm deep-drawing process parameters for AZ91D magnesium alloy sheet based on finite element simulation. To provide guidance for formation of Ni-CNTs/AZ91D composite with more excellent performance, and warm deep-drawing of AZ91D magnesium alloy. And hope to reduce the cost of human and material resources. |
