Additive Manufacturing of Nickel-Base Superalloy Rene N5 through Scanning Laser Epitaxy (SLE) - Material Processing, Microstructures, and Microhardness Properties

Nickel-base superalloy Rene N5 is deposited on cast Rene N5 substrates with [100] and [001] crystallographic orientations through scanning laser epitaxy (SLE) applied to gas-atomized pre-alloyed Rene N5 powder. Single-pass fabrication of crack-free deposits exceeding 1000 micron is achieved. High-resolution optical microscopy reveals that the deposits have 10 times finer primary dendritic arm spacing compared to the substrate. SEM reveals the presence of finer microstructure in the deposit region compared to the substrate region. XRD and EBSD investigations show that the substrate crystallographic orientation does not affect the unidirectional crystal growth in the deposit region. Vickers microhardness values are higher in the deposits compared to the substrate.