8 ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2023 USING X-RAY SCATTERING TO MEASURE NANOCOMPOSITES Researchers at the University of Montpellier, France, are using small- angle x-ray and neutron scattering to measure nanocomposite structures. However, experiments thus far have revealed a surprising lack of nano- particle structure in certain nanocomposite materials whose molecular skeletons are reinforced with nanoparticles previously treated with polymer adsorption. In a new approach, the research team shows that these patterns can only be produced through attractive interactions between nanoparticles with a diverse array of shapes and sizes. The team’s results highlight the rapidly improving capabilities of small-angle scattering instruments and could also help researchers to advance their techniques for studying nanocomposites— with applications in areas including small electronics, biological tissue engineering, and strong, lightweight TESTING | CHARACTERIZATION CUTTING INTO MATERIAL BEHAVIOR To better understand the behavior of metals under extreme conditions, researchers at Texas A&M University, College Station, are utilizing a traditional manufacturing tool—metal cutting. Because the cutting process involves locally shearing or deforming the metal to extreme levels under high rates, the A&M team hypothesized that it could provide fundamental information on the material’s strength, resistance to plastic deformation, or irreversible shape change. According to assistant lead researcher Dinakar Sagapuram, “The research opens a new and interesting application for metal cutting as a property test that material scientists and physicists can use to test their theories. The number of mathematical theories of metal plasticity under high strain rates far outstrips the experimental data. So, the property information obtained using metal cutting can test which theories are valid and which are not.” The team used a high-speed camera to observe how metals deform and shear when they encounter a sharp cutting tool and then use this information to deduce their basic property information. Some advantages of using metal cutting over current testing methods include its simplicity and its ability to produce a range of conditions. These states can be difficult to achieve using conventional tests but are important from the standpoint of various engineering applications. tamu.edu. Triangular holes make this material more likely to crack from left to right. Courtesy of N.R. Brodnik et al./Phys. Rev. Lett. ASTM International recently published ASTM G224, Standard Practice for Operating UVC Lamp Apparatus for Exposure of Materials, outlining basic principles for operating test instruments to evaluate the durability of materials exposed to UVC light. Q-Lab Corp., Westlake, Ohio, led the development of this standard, which provides information on apparatus, specimens, and exposure conditions. astm.org. This side-by-side photo shows how researchers can see different behaviors of metal when it is cut. The gray knife is visible on the right of both photos. Courtesy of Dr. Dinakar Sagapuram. These images reflect the simulation of diversity in nanoparticle sizes: (a) hard spheres; (b) before annealing; and (c) after annealing. (a) (b) (c) BRIEF
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