Tailoring ultra-strong nanocrystalline tungsten nanofoams by reverse phase dissolution

Temperature-dependent mechanical behavior of three-dimensionally ordered macroporous tungsten

“…Nanoporous materials are of interest because their high surface areas can provide enhanced properties benefiting a wide range of technologies. Of particular interest in this study is the fact that the mechanical properties of such materials exhibit length scale effects [1,2,3]. In nanoporous gold, stresses approaching the theoretical shear strength of the material (an upper bound of τ = μ/10, where μ is the shear modulus) have been reported as the ligament diameter decreases below 100 nm [2].…”

“…Nanoporous metals made by dealloying processes have a random arrangement of ligaments and typically possess polycrystalline microstructures and combine the effects of small grain size with the open-pore structure. Open-cell structures made with a number of pure metals, such as Au [1,2,5,6,7], Cu [8], and W [3] can exhibit very high ligament strengths. The ligament strengths are estimated by inverting property scaling laws [2].…”

“…The ligament strengths are estimated by inverting property scaling laws [2]. Nanoporous tungsten made by high-pressure torsion followed by dealloying showed high strength of 5.3 GPa even at a relative density of 65%, corresponding to ligament yield stresses of 2.04 GPa [3]. Meanwhile, 36% dense nanoporous gold with 15 nm thick ligaments shows ligament yield stresses of 1.5 GPa, which is an order of magnitude larger than the yield stresses found in fully dense gold columns [9].…”

“…Synthesis of the 3DOM material as detailed here results in a nanocrystalline microstructure within the ligaments. Given that dense nanocrystalline tungsten thin films exhibit hardness values over 10 GPa (corresponding to a yield strength of approximately 3.4-5 GPa) [3,32], it is postulated that the nanocrystalline microstructure in 3DOM tungsten could enable exceptional yield strengths across a range of temperatures.…”

Size-Dependent Alloying Ability of Immiscible W-Cu Bimetallic Nanoparticles: A Theoretical and Experimental Study

“…At the same time, the crystalline structure, melting point, and electronegativity of W and Cu are quite different. Bulk W-Cu materials are widely used in aerospace, military, electronic information, and other fields [11][12][13][14]. Conventional powder metallurgy methods do not solve the problem of the immiscibility of W and Cu, which results in the outcome that the overall properties of bulk W-Cu materials, such as poor ductility, are insufficient to meet industrial needs.…”