聚变堆包层第一壁缩比部件激光选区熔化成形研究

Selective Laser Melting of Blanket First Wall Reduced Scale Component for Fusion Reactor

目的研究激光选区熔化(SLM)成形第一壁缩比结构的组织性能。方法以316L粉末为原材料,运用Inspire软件对不同成形姿势下第一壁缩比结构的应力与变形情况进行数值模拟,选择最佳成形姿势进行SLM成形,以控制整体变形,并对成形零件进行显微组织观察与力学性能测试。结果实验结果表明,与立放和侧放2种成形姿势相比,平放时残余应力与变形最小,最大残余应力为29.68 MPa,最大变形量为0.29 mm。成形件微观组织呈现各向异性,x-y方向主要为粗大的胞状晶组织,z-x方向为细长的柱状晶组织。力学测试结果显示,x-y方向的抗拉强度为672.1 MPa,伸长率为48.2%,冲击韧性为100.6 J/cm^(2);z-x方向的抗拉强度为646.9 MPa,伸长率64.4%,冲击韧性为136.3 J/cm^(2)。结论组织的差异性主要是由扫描工艺与熔池内部复杂的温度场引起的,微观结构的各向异性会造成力学性能的差异,x-y方向的强度高于z-x方向的,z-x方向上的塑性韧性更高。

The work aims to investigate the microstructure and properties of the first wall reduced scale structure formed by selective laser melting.The stress and deformation of the first wall reduced scale structure under different forming postures were subject to numerical simulation with 316L powder by Inspire software.The best forming posture was selected for SLM to control the overall deformation,and the microstructure observation and mechanical properties test of the formed parts were carried out.The experimental results indicated that the residual stress and deformation were the smallest under flat placement compared with those under vertical and side placement,and the maximum residual stress and deformation could reach 29.68 MPa and 0.29 mm,respectively.The main microstructure of the formed parts presented anisotropic coarse cellular crystal in x-y direction and slender columnar crystal in z-x direction.The mechanical test results showed that tensile strength,elongation and impact toughness in x-y direction were up to 672.1 MPa,48.2%and 100.6 J/cm^(2),respectively and 646.9 MPa,64.4%,136.3 J/cm^(2)in z-x direction.The difference of microstructure is mainly caused by the scanning process and complex temperature field of molten pool.The anisotropy of microstructure results in different mechanical properties and the strength in x-y direction is higher than that in z-x direction,while the higher plasticity and toughness are exhibited in z-x direction.