MICROSTRUCTURE AND MECHANICAL PROPERTY OF LASER DIRECT MANUFACTURING METAL THIN WALL CYLINDER

In this paper, Fe-Cr-B-Si-C alloy powers were used in laser direct manufacture 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 were 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 were fully dense, there were no defects such as crack and pore. There was somewhat grain coarsening in interlayer zone during laser processing, which will 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 was beneficial to molten pool stirring, which lead to smash dendrite structure in favor of microstructure homogenization.