Abstract
A deleterious Laves phase forms in the solidified structure of Inconel 718 (IN718) alloy during laser cladding. However, effective removal methods have not yet been identified. In this study, we first added the IN718 alloy cladding layers with a trace amount of vanadium (V, 0.066 wt.%). Then, we studied the solidification structure of cladding layers using a confocal laser scanning microscope and scanning electron microscopy. The microstructure and Laves phase morphology were investigated. The distribution of niobium (Nb) was observed by experiment as well. We found that V is evenly distributed in dendrites and interdendritic zones. A more refined dendrite structure, reduced second dendrite arm spacing and lower volume fraction of Laves phase were observed in the solidification structure. The results of linear energy-dispersive X-ray spectroscopy (EDS) indicate that the concentration of Nb decreases with an increasing of the distance from the Laves phase. The V-containing sample displayed a relatively slower decreasing tendency. The IN718 alloy sample was harder with the addition of V. In addition, the porosity of the sample decreased compared with the blank sample. The presented findings outline a new method to inhibit the Nb segregation in IN718 alloy during laser cladding, providing reference significance for improving the performance of IN718 alloy samples during actual processing.
Highlights
Laser cladding (Figure 1) is a surface modification technology
The effect of the addition of P and B on Inconel 718 (IN718) alloy as-cast microstructure was studied; the results indicated that the addition of of these
InSolidification this study, we investigated the solidification structure of the V-containing cladding layer
Summary
Laser cladding (Figure 1) is a surface modification technology. Compared with traditional surface strengthening technology, laser cladding has high laser beam energy density, high process efficiency, and fast heating and cooling rates [1,2,3]. Nb is the most important element in IN718 alloy. The addition of Nb has a strong solid solution strengthening effect on Ni–Fe–Cr-based austenite and improves the elastic modulus of the alloy. Nb is the elemental basis for the main strengthening phase of IN718 alloy. One of the most important microscopic characteristics of IN718 alloy is the distribution of
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