Functionally Graded SS 316L to Ni-Based Structures Produced by 3D Plasma Metal Deposition

Abstract

In this investigation, the fabrication of functionally graded structures of SS316L to Ni-based alloys were studied, using the novel technique 3D plasma metal deposition. Two Ni-based alloys were used, a heat resistance alloy Ni80-20 and the solid-solution strengthened Ni625. Different configurations were analyzed, for the Ni80-20 a hard transition and a smooth transition with a region of 50% SS316L/50% Ni80-20. Regarding the structures with Ni625, a smooth transition configuration and variations in the heat input were applied. The effect of the process parameters on the geometry of the structures and the microstructures was studied. Microstructure examinations were carried out using optical and scanning electron microscopy. In addition, microhardness analysis were made on the interfaces. In general, the smooth transition of both systems showed a gradual change in the properties. The microstructural results for the SS316L (both systems) showed an austenite matrix with δ-phase. For the mixed zone and the Ni80-20 an austenite (γ) matrix with some M7C3 precipitates and laves phase were recognized. The as-built Ni625 microstructure was composed of an austenite (γ) matrix with secondary phases laves and δ-Ni3Nb, and precipitates M7C3. The mixed zone exhibited the same phases but with changes in the morphology.

Functionally graded materials classifications and development trends from industrial point of view

“…"Thin FGMs" are manufactured by different methods like physical vapor deposition (PVD) [109], chemical vapor deposition (CVD) [130,131], thermal spray deposition [132] and self-propagating high temperature synthesis (SHS) techniques like laser cladding ( Fig. 8) [133][134][135], while "Bulk FGMs" are manufactured by powder metallurgy [136,137], centrifugal casting [138,139], solid freeform techniques [140], gravity settling.…”

W + Cu and W + Ni Composites and FGMs Prepared by Plasma Transferred Arc Cladding

“…The general benefit of gradually changing composition (so-called functionally graded material (FGM)) lies in the reduction of stress concentration that would otherwise occur at a sharp interface of two dissimilar materials upon thermal loading [ 6 , 20 ]. FGM formation by PTA and similar techniques was described in [ 21 , 22 ].…”

Processing by Additive Manufacturing Based on Plasma Transferred Arc of Hastelloy in Air and Argon Atmosphere

“…When the wire is employed, the technique could be considered as one of the wire arc additive manufacturing (WAAM) processes, in addition to tungsten inert gas/metal inert gas (TIG/MIG) [12]. The PTA is included in the recently named group 3D Plasma Metal Deposition (3DPMD) that belongs to the category of directed energy deposition processes [13][14][15]. This manufacturing process permits us to carry out the fabrication of specimens with larger dimensions than specimens produced by powder bed techniques.…”