Strong and ductile titanium-oxygen-iron alloys by additive manufacturing.

Titanium alloys are advanced lightweight materials, indispensable for many critical applications1,2. The mainstay of the titanium industry is the α-ß titanium alloys, which are formulated through alloying additions that stabilize the α and ß phases3-5. Our work focuses on harnessing two of the most powerful stabilizing elements and strengtheners for α-ß titanium alloys, oxygen and iron1-5, which are readily abundant. However, the embrittling effect of oxygen6,7, described colloquially as 'the kryptonite to titanium'8, and the microsegregation of iron9 have hindered their combination for the development of strong and ductile α-ß titanium-oxygen-iron alloys. Here we integrate alloy design with additive manufacturing (AM) process design to demonstrate a series of titanium-oxygen-iron compositions that exhibit outstanding tensile properties. We explain the atomic-scale origins of these properties using various characterization techniques. The abundance of oxygen and iron and the process simplicity for net-shape or near-net-shape manufacturing by AM make these α-ß titanium-oxygen-iron alloys attractive for a diverse range of applications. Furthermore, they offer promise for industrial-scale use of off-grade sponge titanium or sponge titanium-oxygen-iron10,11, an industrial waste product at present. The economic and environmental potential to reduce the carbon footprint of the energy-intensive sponge titanium production12 is substantial.

Microstructure and Its Effect on the Magnetic, Magnetocaloric and Magnetostrictive Properties of Tb55Co30Fe15 Glassy Ribbons.

In the present work, the microstructure and its effect on the magnetic, magnetocaloric, and magnetoelastic properties of the Tb55Co30Fe15 melt-spun ribbon were investigated. The ribbon exhibits typical amorphous characteristics in its X-ray diffraction examination and differential scanning calorimetry measurement. However, the magnetic properties of the ribbon indicate that the ribbon is inhomogeneous in the nanoscale, as ascertained by a high-resolution electron microscope. Compared to the Tb55Co45 amorphous alloy, the Tb55Co30Fe15 ribbon shows poor magnetocaloric properties but outstanding magnetostriction. A rather high value of reversible magnetostriction up to 788 ppm under 5 T was obtained. The mechanism for the formation of nanoparticles and its effect on the magnetocaloric and magnetostrictive properties were investigated.

Additive Manufactured Graphene Coating with Synergistic Photothermal and Superhydrophobic Effects for Bactericidal Applications.

Drug-resistant bacterial infection is a global threat to public health due to the high mobility of the population. Novel therapy methods have been intensively studied for the eradication of antibiotic-resistant bacteria, including photothermal treatment, which has established outstanding bacterial killing efficiencies under laser radiation, and superhydrophobic surfaces have exhibited excellent antifouling properties. However, an effective, scalable, and affordable bactericidal coating for eliminating drug-resistant bacteria is lacking. Herein, a novel graphene coating using one-step laser-induced graphene and simultaneous laser-induced forward transfer is introduced. The graphene coating shows high photothermal conversion and superhydrophobic performance, and these synergistic effects can make the bacteria number decrease with over 99.99% proportions under one sun illumination. The superhydrophobic properties can also reduce 99.87% of bacteria compared to the control sample when the solar energy is not available. This additive and scalable method can quickly coat functional graphene onto various substrates, with bacterial applications in many areas, such as water pipeline robots.

Wearable Fluid Capture Devices for Electrochemical Sensing of Sweat.

Wearable sensing technologies are vital for realizing personalized health monitoring. Noninvasive human sweat sampling is essential for monitoring an individual's physical state using rich physiological data. However, existing wearable sensing technologies lack the controlled capture of body sweat and in performing on-device measurement without inflammatory contact. Herein, we report the development of a wearable sweat-capture device using patterned graphene arrays with controlled superwettability and electrical conductivity for simultaneously capturing and electrochemically measuring sweat droplets. The sweat droplets exhibited strong attachment on the superhydrophilic graphene patterns, even during moderate exercising. The captured sweat droplets present strong electrochemical signals using graphene films as the working electrode and metal pins as the counter electrode arrays assembled on 3D printed holders, at the detection limit of 6 µM for H2O2 sensing. This research enables full-body spatiotemporal mapping of sweat, which is beneficial for a broad range of personalized monitoring applications, such as drug abuse detection, athletics performance optimization, and physiological wellness tracking.