A polycrystalline Cu foam with sub-micron ligament sizes was formed by creating a non-woven fabric via electrospinning with a homogeneous mixture of polyvinyl alcohol(PVA)-and copper acetate(Cu(Ac)2). Thermogravimetric measurement of the electrospun fabric of the precursor solution is reported. Oxidizing the precursor fabric at 773K formed an oxide nano-foam; subsequent heating at 573K with a reducing gas transformed the CuO nano-foam to Cu with a similar ligament and meso-scale pore size morphology. A cross-section prepared by focused ion beam lift-out shows the polycrystalline structure with multi-scale porosity. The mechanical property of the Cu nano-foam is measured by nano-indentation. The load-depth curves and deduced mechanical properties suggest that additional intra-ligament pores lead to unique structure-property relations in this non-conventional form of metal.
Selective laser melting (SLM) is an additive manufacturing (AM) technology proven to produce near fully dense components made of a wide number of materials and with the required printing resolution to manufacture structures with microscopic structural details. Because of complexity of the processing and tensile and fatigue relationships, SLM requires more investigation. For instance, the shielding gas flow (argon flow) has affected the stability of the process and consequently the quality of AM components. In addition to provide an inert atmosphere during the printing process, the argon flow removes process byproducts, such as spatter and smoke that occur during the SLM. Inefficient argon flow results in the interaction of the laser beam with the by-products, leading to the redeposition of these onto the melt pool. This has a negative impact on the surface morphology, density of the parts, and ultimately mechanical performance. In this study we investigated two argon flows (optimized vs. nonoptimized) and their effects on the tensile properties and surface finish of Ti-6Al-4V samples (stress relieved) with different size dimensions and printing directions (horizontal vs. vertical). For the nonoptimized argon flow, we found tensile properties that ranged from 826 to 1,052 MPa ultimate tensile strength (UTS), 925 to 966 MPa yield strength (YS), and 0.6–17% elongation (Elong.). The optimized flow exhibited more consistent results, as follows: 998–1,039 MPa UTS, 878–940 MPa YS, and 15–17% Elong. No statistical difference was found on the average surface roughness for samples printed in the vertical direction (7.26 μm Ra, and 47.90 μm Rz), regardless of the argon flow used. For the horizontal direction, however, the optimized flow showed a smoother surface finish (6.48 μm Ra, 39.46 μm Rz) compared with the nonoptimized flow (11.72 μm Ra, 71.13 μm Rz). The effects of argon flow on density and metallurgical characteristics of printed parts also were discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.