超音速沉积Stellite6颗粒与激光复合工艺的数值模拟研究

发布时间：2018-03-20 11:36

  本文选题：超音速激光沉积　切入点：数值模拟　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：超音速激光沉积是基于冷喷涂与激光工艺的结合而发展起来的涂层工艺。通过激光对材料的加热作用,可以提高冷喷涂层的厚度、沉积效率、致密性以及颗粒与基体的结合强度,并且可以实现难沉积材料涂层的制备,保持沉积粉末的结构和性能。由于这些优势的存在,超音速激光沉积技术成为了一种可选择的具有吸引力的技术。超音速激光沉积工艺中,能否获得有效的沉积层,取决于沉积颗粒与基体及颗粒与颗粒间的变形行为,由于高速粒子碰撞变形瞬时性特点,颗粒与基体变形行为不易直接观察,所以本文利用有限元分析软件ANSYS/LS-DYNA来模拟颗粒沉积到基体的碰撞过程。首先选取Johnson-Cook材料模型和双线性各向同性硬化材料模型,建立超音速激光沉积三维模型,对两种材料模型在不同入射速度、不同沉积点温度下,Cu颗粒碰撞45钢基体的沉积过程进行了模拟分析,验证双线性各向同性硬化材料模型在超音速沉积Stellite6颗粒与激光复合工艺中的可行性。选用双线性各向同性硬化材料模型,对超音速激光沉积工艺中Stellite6颗粒与45钢基体碰撞结合过程进行了数值模拟分析,研究了单颗粒不同入射角度对颗粒与基体变形行为的影响,并分析研究了不同碰撞速度、不同沉积处温度对多颗粒撞击基体变形行为的影响。结果表明:(1)常温下颗粒撞击速度为800m/s和基体预热温度850℃、颗粒速度为500m/s时,Cu颗粒与45钢基体紧密结合形成致密涂层。Johnson-Cook材料模型和双线性各向同性硬化材料模型仿真结果一致,两种模型都能用于预测超音速激光沉积工艺参数。(2)颗粒的入射角度小于20°时,颗粒与基体能形成紧密结合,而当颗粒的入射角度大于20°时,颗粒与基体不能形成紧密结合。(3)多颗粒碰撞基体的过程中,在邻近颗粒间的交互作用及后续颗粒的夯实作用下,颗粒会变形,当颗粒与颗粒间变形相匹配时,颗粒间的间隙减小,形成致密结合。(4)通过激光加热作用改善基体的力学性能和材料特性,Stellite6颗粒能沉积到45钢基体上。
[Abstract]:Supersonic laser deposition is a coating process developed based on the combination of cold spraying and laser technology. The thickness and deposition efficiency of cold spray coating can be improved by heating the material by laser. Compactness and the bonding strength of particles to the substrate, and the preparation of coatings of refractory materials to maintain the structure and properties of deposited powders. Supersonic laser deposition technology has become an attractive alternative technology. In supersonic laser deposition process, the availability of effective deposition depends on the deformation behavior between deposition particles and matrix and between particles and particles. Because of the instantaneous characteristics of high velocity particle collision deformation, it is difficult to observe the deformation behavior of particle and matrix directly. In this paper, the finite element analysis software ANSYS/LS-DYNA is used to simulate the collision process of particles deposited into the matrix. Firstly, the Johnson-Cook material model and the bilinear isotropic hardening material model are selected to establish the three-dimensional model of supersonic laser deposition. The deposition process of two material models with different incident velocities and different deposition temperature on 45 steel matrix was simulated and analyzed. To verify the feasibility of bilinear isotropic hardening material model in supersonic deposition of Stellite6 particles and laser composite process, a bilinear isotropic hardening material model is used. In this paper, the collision process between Stellite6 particles and 45 steel matrix in supersonic laser deposition process is numerically simulated and analyzed. The effects of different incident angles of single particles on the deformation behavior of particles and matrix are studied, and the different collision velocities are analyzed. The results show that the particle impact velocity is 800 m / s and the substrate preheating temperature is 850 鈩，

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