@article{hankwitz_ledford_rock_o'dell_horn_2021, title={Electron Beam Melting of Niobium Alloys from Blended Powders}, volume={14}, ISSN={["1996-1944"]}, DOI={10.3390/ma14195536}, abstractNote={Niobium-based tungsten alloys are desirable for high-temperature structural applications yet are restricted in practice by limited room-temperature ductility and fabricability. Powder bed fusion additive manufacturing is one technology that could be leveraged to process alloys with limited ductility, without the need for pre-alloying. A custom electron beam powder bed fusion machine was used to demonstrate the processability of blended Nb-1Zr, Nb-10W-1Zr-0.1C, and Nb-20W-1Zr-0.1C powders, with resulting solid optical densities of 99+%. Ultimately, post-processing heat treatments were required to increase tungsten diffusion in niobium, as well as to attain satisfactory mechanical properties.}, number={19}, journal={MATERIALS}, author={Hankwitz, Jameson P. and Ledford, Christopher and Rock, Christopher and O'Dell, Scott and Horn, Timothy J.}, year={2021}, month={Oct} }
 @article{ellis_sprayberry_ledford_hankwitz_kirka_rock_horn_katoh_dehoff_2021, title={Processing of tungsten through electron beam melting *}, volume={555}, ISSN={["1873-4820"]}, DOI={10.1016/j.jnucmat.2021.153041}, abstractNote={Additive manufacturing (AM) presents a new design paradigm for the manufacture of engineering materials through the layer-by-layer approach combined with welding theory. In the instance of difficult to process materials such as tungsten and other refractory metals, AM offers an opportunity for radical redesign of critical components for next-generation energy technologies including fusion. In this work, electron beam powder bed fusion (EB-PBF) is applied to process pure tungsten to study the influence of process parameters on the defect density of the material. An in-situ image analysis algorithm is applied to pure tungsten for the first time, and is used to visualize the defect structure in AM tungsten. Finally, a cracking mechanism for AM tungsten is proposed, and suggestions for suppression of cracks in pure tungsten are offered.}, journal={JOURNAL OF NUCLEAR MATERIALS}, author={Ellis, Elizabeth A. I. and Sprayberry, Michael A. and Ledford, Christopher and Hankwitz, Jameson P. and Kirka, Michael M. and Rock, Chris D. and Horn, Timothy J. and Katoh, Yutai and Dehoff, Ryan R.}, year={2021}, month={Nov} }
 @article{roh_okello_golbasi_hankwitz_liu_tracy_velev_2019, title={3D-Printed Silicone Soft Architectures with Programmed Magneto-Capillary Reconfiguration}, volume={4}, ISSN={["2365-709X"]}, DOI={10.1002/admt.201800528}, abstractNote={AbstractSoft intelligent structures that are programmed to reshape and reconfigure under magnetic field can find applications such as in soft robotics and biomedical devices. Here, a new class of smart elastomeric architectures that undergo complex reconfiguration and shape change in applied magnetic fields, while floating on the surface of water, is reported. These magnetoactive soft actuators are fabricated by 3D printing with homocomposite silicone capillary ink. The ultrasoft actuators easily deform by the magnetic force exerted on carbonyl iron particles embedded in the silicone, as well as lateral capillary forces. The tensile and compressive moduli of the actuators are easily determined by their topological design through 3D printing. As a result, their responses can be engineered by the interplay of the intensity of the magnetic field gradient and the programmable moduli. 3D printing allows us to fabricate soft architectures with different actuation modes, such as isotropic/anisotropic contraction and multiple shape changes, as well as functional reconfiguration. Meshes that reconfigure in magnetic fields and respond to external stimuli by reshaping could serve as active tissue scaffolds for cell cultures and soft robots mimicking creatures that live on the surface of water.}, number={4}, journal={ADVANCED MATERIALS TECHNOLOGIES}, publisher={Wiley}, author={Roh, Sangchul and Okello, Lilian B. and Golbasi, Nuran and Hankwitz, Jameson P. and Liu, Jessica A-C and Tracy, Joseph B. and Velev, Orlin D.}, year={2019}, month={Apr} }