Microstructure and mechanical properties of rapid directionally solidified Ni-base superalloy Rene′41 by laser melting deposition manufacturing

Ni-base superalloy Rene′41 was produced by the laser melting deposition (LMD) manufacturing process. The microstructure was characterized by optical and scanning electron microscopy and X-ray diffraction. Results showed that ultra-fine rapid directionally solidified columnar grains with some fine MC carbide particles in the interdendritic zone were formed in the as-deposited samples along the deposited-direction due to the high thermal gradient and solidification cooling rate. The columnar grains were composed of well oriented cellular dendrites with a primary arm spacing of approximately 35 μm. The size of γ′ precipitates in the dendritic cores was larger than that in the interdendritic zones. Mechanical test data have shown that the LMD material had good high-temperature mechanical properties along longitudinal section.