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Analysis of Mechanical and Thermal Properties of Aluminum-Chromium-Nitride-Coated Stainless Steel 316L Micrometal Lattice Fabricated by Selective Laser Sintering Dinesh Kumar Ravikumar, Sandeep Ragavan, and Sangeetha Dharmalingam (Submitted March 30, 2020; in revised form September 19, 2020; Accepted: 23 September 2020) Cellular materials, especially ordered lattice structures, contain lesser quantity of material than their bulk counterparts. Only a few researches are focused on composite microlattices and their performance at high temperatures. The aim of this scientific work is to analyze the thermal and mechanical properties and corrosion resistance of stainless steel 316L micrometal lattice (MML) fabricated by selective laser sintering method and to compare the thermal properties and corrosion resistance of aluminum-chromium-nitridecoated stainless steel 316 MML with that of the uncoated MML. The coating on the fabricated MML is done by physical vapor deposition. The coated and uncoated MMLs are subjected to dilatometry, corrosion test, thermogravimetric analysis (TGA) and differential scanning calorimetry and SEM analysis, whereas the uncoated MML was subjected to tension test and compression test in addition to the above-said tests. Simulation of these MML structures is carried out to correlate the results obtained, with the real-time test results. In compression test, the MMLs withstand a higher load owing to their octahedral arrangement of struts, which aided in uniform load distribution throughout the lattice. Also, the coated samples are found to be less prone to oxidation when subjected to high temperature as the coating prevented the formation of oxide, whereas the uncoated sample oxidized at higher temperatures as indicated by a considerable mass gain in the TGA plot and from the EDS analysis, which indicates the presence of oxygen in the uncoated MML. Another key result to be noted is that the uncoated MML distorted to a greater extent than the coated MML at higher temperatures as indicated from the dilatometry tests. These findings will be of use in future design/manufacturing optimizations in aerospace and automotive industries which require lightweight and high strength materials.

Dinesh Kumar Ravikumar, Sandeep Ragavan, and Sangeetha Dharmalingam, Department of Mechanical Engineering, Anna University, Chennai 600 025, India. Contact e-mail: [email protected].

Journal of Materials Engineering and Performance

Keywords

cellular, composite, micrometal lattice, octahedral, selective laser sintering, simulation

1. Introduction Development of high strength and low weight materials is of primary interest, particularly for aerospace applications. These materials must have high strength to weight ratio, i.e., high specific strength and low density (Ref 1, 2). Right from 1920s, with the invention of aircraft, materials used in the construction of an aircraft saw huge evolution, from ply woods and fabrics, to complete metal structures made of steel and aluminum. Ad