Nickel Aluminum Bronze (NAB) alloy fabricated via Laser Powder Bed Fusion (LPBF) using a heated platform
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Date
2025-08
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University of New Brunswick
Abstract
This research investigates the influence of a heated platform on microstructural characteristics, mechanical properties, and corrosion behavior of the nickel aluminum bronze alloy (NAB C95800) fabricated using the laser powder bed fusion (LPBF) technique. The microstructure of the LPBF-NAB sample exhibited due to the rapid cooling rates inherent to the LPBF process, a fine microstructure comprising Widmanstätten α and martensitic β′ phases was observed. Transmission electron microscopy (TEM) confirmed the presence of κ precipitates, which are attributed to the use of a heated platform during the layer-by-layer powder deposition. To evaluate the mechanical performance, uniaxial tensile tests were conducted on flat, bone-shaped specimens, with strain distribution across the gauge section monitored via digital image correlation (DIC). The results demonstrated remarkable yield strength of 646±20 MPa and ultimate tensile strength of 1056±20 MPa, which are likely due to the presence of κ precipitates and the associated precipitation hardening mechanism. The elongation of the sample was about 5.65% at the rupture stress. To evaluate the corrosion resistance of LPBF-NAB samples, electrochemical tests were performed, and the results were compared with those of conventionally cast counterparts. The cyclic potentiodynamic polarization (CPP) curves exhibited that the corrosion resistance of both samples are comparable. However, the number and size of the pits formed on the surface of the cast sample were lower than those produced via the heated platform LPBF method after the corrosion test.