In this study, pulse‐width modulation of laser power was identified as a feasible means for varying the chemical gradient in copper—nickel‐graded materials. Graded material deposits of 70 wt. %. copper‐30 wt. %. nickel on 100 wt. %. nickel and vice versa were deposited and characterized. The 70/30 copper—nickel weight ratio in the feedstock powder was achieved through blending elemental copper and 96 wt. %. Ni—Delero‐22 alloy. At the dissimilar material interface over the course of four layers, the duty cycle of power was ramped down from a high value to optimized deposition conditions. This change was theorized to influence the remelting and deposition height, and by extension, vary the chemistry gradient. X‐ray Energy Dispersive Spectroscopy (EDS) analysis showed significant differences in the span and nature of chemistry gradient with varying duty cycles. These observations were also supported by the variation in microhardness values across the interface. The influence of different chemistry gradients on the tensile performance was observed through mini‐tensile testing, coupled with Digital Image Correlation (DIC). The strain fields from the DIC analysis showed variations in strain for different chemistry gradients. The strength measurements from these specimens were also different for different chemistry gradients. The site of failure was observed to always occur within the copper-rich region.
S. Karnati et al., "On the Feasibility of Tailoring Copper-Nickel Functionally Graded Materials Fabricated through Laser Metal Deposition," Metals, vol. 9, no. 3, MDPI AG, Mar 2019.
The definitive version is available at https://doi.org/10.3390/met9030287
Mechanical and Aerospace Engineering
Materials Science and Engineering
Intelligent Systems Center
Keywords and Phrases
Blended elemental powders; Digital image correlation; Functionally graded materials; Laser metal deposition; Miniature tensile testing; X-ray energy dispersive spectroscopy
International Standard Serial Number (ISSN)
Article - Journal
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01 Mar 2019