We demonstrate a three phase-grating moiré neutron interferometer in a highly intense neutron beam as a robust candidate for large area interferometry applications and for the characterization of materials. This novel far-field moiré technique allows for broad wavelength acceptance and relaxed requirements related to fabrication and alignment, thus circumventing the main obstacles associated wi...

We report experimental observations on the evolution of acoustic entropy in the course of cyclic loading as degradation occurs due to fatigue. The measured entropy is a result of the materials’ microstructural changes that occur as degradation due to cyclic mechanical loading. Experimental results demonstrate that maximum acoustic entropy emanating from materials during the course of degradatio...

Although very accurate in representing the material anisotropy, finite element analysis based on direct use of a polycrystal model is CPU-intensive (Guan et al., 2006a). In the present study, this Taylor-type polycrystalline model was firstly used to predict the anisotropy coefficients of Yld96 yield function. Then this phenomenological anisotropic yield function was implemented into ABAQUS/Sta...

The role of loading rate and fluid properties in the fracture of piping under internal explosions is an important issue for designers and accident analysis. This was examined by fracture experiments on thin-walled and preflawed aluminum 6061-T6 tubes. The tubes were 1) statically loaded with oil, 2) statically loaded with nitrogen, and 3) dynamically loaded with gaseous detonations traveling at...

Continuous production of Al 6061-T6 particulate using modulation-assisted machining (MAM) is demonstrated. Superimposition of a controlled, low-frequency modulation in conventional machining causes chips to form as discrete particles. By adjusting the conditions, equiaxed, platelet and fiber-shaped particles having narrow size distributions can be produced. Large-strain deformation leads to mic...

Science, a weekly journal, is published each Friday by the American Association for the Advancement of Science at Mt. Royal & Guilford Avenues, Baltimore 2, Maryland. Founded in 1880, it has been since 1900 the official publication of the AAAS. Editorial, Advertising, and Circulation Offices, 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Telephone, EXecutive 6060 or 6061. Cable address S...

In an effort to maximize grain growth of open-die forged 6061 aluminum alloy parts, samples from three of Weber Metals’s suppliers (Hidal Co-Almex USA Inc., TST Inc., and Vista Metals Corp.; to be called Supplier H, Supplier T, Supplier V respectively) were cut into cylinders with diameters of 0.75 ̋ and heights of 2 ̋, and put through a simulated forging process and heat treatment. It is possibl...

Plane-strain machining can be used to impart large plastic strains in alloys that are difficult to deform by other severe plastic deformation (SPD) processes. By cutting at low speeds, the heating caused by friction with the tool can be reduced to insignificant levels. The utility of this approach for characterizing microstructure development in SPD is demonstrated using a variety of commercial...