Characterization of Inconel 718 Processed by Laser Metal Deposition (LMD)
H. Elgazzar and Y. H. Elbashar
Inconel 718 is widely used in several industries in the form of high added value components such as gears and turbine blade owing to its pronounced combination mechanical properties and structural stability at high temperatures. The IN718 components often have complex shapes that are difficult to manufacture using conventional machining. Recently there is a growing interest in additive manufacturing (AM) practically laser metal deposition (LMD) due to its ability to manufacture three-dimensional (3-D) complex products from Inconel 718; however, the LMD products suffer from defects such as cracks, porosity and lack of adhesion due to using low-quality powder and/ or improper processing parameters. This study focuses on the deposition of Inconel 718 on 304 stainless steel substrates at low heat input, aiming to obtain cracks free products. The effect of specific energy, laser interaction time and powder mass flow rate on the characteristics of the deposited layers such as surface roughness, layer height, dilution, microstructure, and hardness were investigated. The results showed that all specimens are crack-free at all levels of experiments, few pores were observed in some specimens; however, the using of low heat input comes at the expense of low layers height.
Keywords: Nd:YAG laser, Inconel 718, 304 stainless steel, laser metal deposition (LMD), cracks, porosity