1,723,155 research outputs found
The morphology of the odontophore of Longidorus litchii Xu & Cheng, 1992 (Nematoda : Longidoridae)
No full textThe morphology of the odontophore of Longidorus litchii Xu & Cheng, 1992, is described and depicted in photomicrographs from specimens collected from the locality of the type habitat i.e. clay soil around roots of litchi trees (Litchi chienesis Sonn) in Zhangzhou, Fujian province, eastern China. The odontophore is swollen and has a tri-radiate base containing well developed flanges. These taxonomically important characteristics were not reported in the original description of the species
Developing processing routes for the equal-channel angular pressing of age-hardenable aluminum alloys
No full textThe processing of age-hardenable aluminum alloys by equal-channel angular pressing (ECAP) was investigated using three different Al-Zn-Mg alloys. The results show that it is relatively easy to conduct the ECAP at an elevated temperature of 473 K, but this leads to a weakening of the alloy rather than a strengthening. The processing by ECAP may be performed successfully at room temperature provided it is conducted fairly quickly (within ~10 minutes) after quenching from the solution treatment. It is necessary also to optimize the solution treatment conditions for each alloy composition. Under optimum conditions, good strengthening is achieved even after a single pass in ECAP. This article is based on a presentation given in the symposium entitled “Mechanical Behavior of Nanostructured Materials,” which occurred during the TMS Spring Meeting in San Francisco, CA, February 15–19, 2009, under the auspices of TMS, the TMS Electronic, Magnetic, and Photonic Materials Division, the TMS Materials Processing and Manufacturing Division, the TMS Structural Materials Division, the TMS Nanomechanical Materials Behavior Committee, the TMS Chemistry and Physics of Materials Committee, and the TMS/ASM Mechanical Behavior of Materials Committee.<br/
Creep and superplasticity in a spray-cast aluminum alloy processed by ECA pressing
No full textA commercial spray-cast aluminum 7034 alloy, having a composition of Al–11.5% Zn–2.5% Mg–0.9% Cu–0.2% Zr, was processed by equal-channel angular pressing (ECAP) at a temperature of 473 K to reduce the grain size from ~2.1 to ~0.3 ?m. Microstructural observations revealed a breaking of the rod-like MgZn2 precipitates during ECAP. Static annealing showed the ultrafine grain size was reasonably stable up to a temperature of 673 K. Tensile and creep tests were conducted using specimens cut from the unpressed bars and from billets processed by ECAP. In tensile testing at 673 K, the results on the as-pressed alloy show a potential for achieving high superplastic elongations to failure of >1000% at stain rates at and above 10?2 s?1. In creep testing at 473 K, the creep rates recorded for the as-pressed samples were significantly faster, by about two orders of magnitude, than for the unpressed alloy
Three-dimensional representations of hardness distributions after processing by high-pressure torsion
No full textThe Vickers microhardness was recorded on the polished surfaces of disks of pure aluminum and an Al-6061 alloy after processing by high-pressure torsion. The results are shown in three-dimensional representations that reveal clearly the gradual evolution towards a homogeneous structure. This evolution is reasonably rapid in pure Al but it is slower in the alloy due to the lower rate of recovery. The results show evolution is assisted by increasing the numbers of turns and/or the imposed pressure. The results reveal significant differences between pure Al and the Al-6061 alloy which are consistent with earlier results obtained during processing by equal-channel angular pressing
Data for Group IV mid-infrared photonics
No full textExperimental data for the plots shown in the paper Mashanovich, G, Nedeljkovic, M, Soler Penades, J, Qu, Z, Cao, W, Osman, A, Wu, Y, Stirling, C, Qi, Y, Xu Cheng, Y, Reid, L, Littlejohns, CG, Jian, K, Zhao, Z, Takenaka, M, Li, T, Zhou, Z, Gardes, F, Thomson, D & Reed, G 2018, 'Group IV mid-­infrared photonics' Optical Materials Express.</span
Mechanical characteristics of a Zn-22% Al Alloy processed to very high strains by ECAP
No full textA Zn–22% Al eutectoid alloy was processed by equal-channel angular pressing for various numbers of passes up to a maximum of 24. Observations show the as-pressed grain size remains constant between 4 and 24 passes and the stress–strain behavior at room temperature is essentially independent of the number of imposed passes when using strain rates of 1.0 × 10?3 and 1.0 × 10?2 s?1. The results provide no evidence for a critical imposed strain marking the onset of higher ductilities
Evaluating the influence of pressure and torsional strain on processing by high-pressure torsion
No full textTests were conducted on an Al-6061 alloy to evaluate the separate effects of the applied pressure and the torsional straining in processing by high-pressure torsion (HPT). The values of the Vickers microhardness were measured after processing and plotted both linearly across the diameters of the disks and as three-dimensional representations. The measurements show that the applied pressure increases the hardness in the absence of torsional straining. In the presence of a pressure and torsional straining, the hardness values are high at the edges of the disk but lower in the central region. There is a gradual evolution toward a hardness homogeneity with increasing numbers of HPT revolutions. The hardness values at the edges of the disks are reasonably independent of the applied pressure but the extent of this region of high hardness depends upon both the applied pressure and the numbers of turns in the HPT processing
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