【摘要】 选区激光熔化是由线及面、再由面及体的逐行、逐层增材制造技术，作为其成型工艺基础的激光对粉末线扫描熔化的熔道形貌及尺度，对三维结构的成型和质量有着直接影响。为此，建立了TC4粉末在激光作用下的粉末熔化、熔体流动和熔道冷却的全过程仿真模型，以进行基础工艺参数优化；并与成型试验相结合，在粉层厚度分别为25、40和55μm,进一步优化得到的成型工艺的激光线能量密度范围分别为0.060～0.115、0.110～0.182和0.210～0.252 J/mm时，能够稳定地获得熔宽均匀的熔道；在其基础上，以优化的单熔道工艺参数实现了高度为1.7 mm、壁厚为118μm的薄壁结构三维成型，为利用SLM技术进行薄壁类结构的成型提供了基础。更多还原

【Abstract】 Selective Laser Melting(SLM) is a category of additive manufacturing technology which forms layers from lines then volumes from layers to achieve line-by-line and layer-by-layer manufacturing. Formation via lineal laser scanning is its basal process, in which the tracks′ geometry and scales formed this way has a direct impact on the formation of surfaces and 3 D structures. Therefore, an overall simulation model that includes powder melting, pool flowing and track cooling process of TC4 powder under the action of laser was established, from which the basal process parameters could be optimized. Furthermore, an experiment was carried out to conclude that with a powder thickness of 25,40 and 55 μm respectively, laser linear energy density corresponding ranges of 0.060～0.115,0.110～0.182,and 0.210～0.252 J/mm were feasible to reliably acquire straight tracks of stable wideness.Based on the optimized parameters of single-track formation, further experiments succeeded in forming 3 D thin-walled structures with a height of 1.7 mm and a wall thickness of 118 μm.The optimized process serves as a basis for parameters selection for SLM formed thin-walled structures.更多还原