Laser engineered net shaping of Co-based superalloys
(1.北京市装甲兵工程学院机械工程学院
2.Department of Mechanical Engineering, Academy of Armored Force Engineering, Beijing 100072, China
3.National Key Laboratory for Remanufacturing Institute, Academy of Armored Forces Engineering, Beijing 100072, China)
2.Department of Mechanical Engineering, Academy of Armored Force Engineering, Beijing 100072, China
3.National Key Laboratory for Remanufacturing Institute, Academy of Armored Forces Engineering, Beijing 100072, China)
Abstract: Laser engineered net shaping(LENS) process was investigated using Co-based superalloy powder with a high power continuous wave CO2 laser. Thin wall part with smooth surface was obtained by LENS of layer-by-layer deposition of the powder materials. This thin wall sample was tested for metallographic examinations, micro-hardness, X-ray diffraction and mechanical property test. Microstructural results show that the layers possess rapid solidification microstructural feature, fine dendritic crystal and M7C3-type carbides (essentially chromium-rich carbide) dispersed in the γ(Co,Cr) phase matrix. Dendrite spacing as well as the solidification mode can be controlled through control process parameters. In addition, this microstructural feature of the as-formed Co-base sample leads to an evident hardening and a superior tensile strength and toughness.
Key words: laser engineered net shaping (LENS); Co-based superalloy; microstructure; mechanical properties