Hardness, chemical, and microstructural studies for laser-fabricated metal parts of graded materials

Laser deposition of metal layers has been recognized, in recent years, as a one-step process to fabricate metal parts instead of the two-step process of producing a mold and then using the mold to cast a metal part. The authors have employed this one-step technique to create graded materials by varying the part's composition from 100% stainless steel to a 100% nickel-based superalloy. Mechanical properties of these graded materials are measured and the effects of slow solidification rates are investigated. A multimode CO2 laser is operated at 270 W to produce wall-like structures of graded materials. The CO2 laser beam is focused to a spot size of 600 mu m using a 127 mm focal length lens. (C) 2000 Laser Institute of America. [S1042-346X(00)00405-8].