激光直接制造是一种全新的制造技术。采用Fe-Cr-B-Si-C 铁基合金粉末利用激光直接制造技术制备了单道激光熔覆层和薄壁圆筒零件。运用金相显微镜（OM）、X 射线能谱仪（EDX）、X 射线衍射（XRD）和纳米压痕技术研究了单道激光熔覆层和薄壁圆筒零件的显微组织、物相结构和纳米力学性能。研究结果表明，激光直接制造金属零件组织致密、未出现裂纹和气孔等缺陷；层间组织发生了粗化，导致层间力学性能弱化，但整体性能较高，能够满足实际零件的使用性能要求；激光扫描方向的改变有利于熔池的搅拌作用，枝晶组织发生了碎化，有利于组织的均匀化。

Laser direct manufacturing is a novel manufacturing technology. Fe-Cr-B-Si-C alloy powders are used in laser direct manufacture to make single track laser cladding layer and thin wall cylinder. The microstructure, phase structure and mechanical properties of single track cladding layer and thin wall cylinder are investigated by optical microscopy (OM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and nano-indentation techniques. The results show that laser direct forming metal parts are fully dense, and that there are no defects such as crack and pore. There is somewhat coarsening during interlayer microstructure, which can lead to weak mechanical properties. However, the whole properties of the thin wall cylinder may still satisfy the real part performance requirements. The change of laser scanning direction is beneficial to molten pool stirring, which leads to smashed dendrite structure in favor of microstructure homogenization.