New extractants for Cu 2+ ions in raw ore powders or waste water (fluid) were successfully synthesized recently in good yields.Their structures and purity were confirmed by 1 H NMR and IR.
Additively manufactured stainless steels have become increasingly popular due to their desirable properties, but their mechanical behavior in structural parts is not yet fully understood. Specifically, the impact of columnar microstructures on fatigue behavior is still unclear. A typical directed energy deposition (DED)‐fabricated 316L stainless steel microstructure consists of distinct zones with equiaxed and columnar grains. To answer the question of how these zones of a DED‐fabricated 316L stainless steel microstructure affect the local mechanical behavior individually, such as the fatigue strength, stress/strain distribution, and fatigue life, crystal plasticity simulations are conducted to investigate the influence of microstructure on local mechanical behavior such as fatigue strength, stress/strain distribution, and fatigue life. The simulations find that columnar microstructures exhibit better fatigue strength than equiaxed structures when the load is parallel to the major axis of the columnar grains, but the strength decreases when the load is perpendicular. This study also uses machine learning to predict fatigue life, which shows good agreement with crystal plasticity modeling. The study suggests that the combined crystal plasticity–machine learning approach is an effective way to predict the fatigue behavior of additively manufactured components.
Abstract Aiming at the demand of precise forming of large-scale high-performance lightweight components with inner ring reinforcement, a new multi-directional loading rotary extrusion forming technology is developed, which matches the linear motion with the rotary motion and actively increases the strong shear force. Its principle is that while the blank is axially extruded and loaded, the radial force and rotating torque are increased. Through the synergistic action of axial, radial and rotating motion, the orderly flow of metal is controlled and the cumulative severe plastic deformation (SPD) of "uplift-trowel" micro area is generated, so as to realize the uniform strengthening and toughening of materials. At the same time, through the continuous deformation of punch "ellipse-circle", high reinforcement is grown on the cylinder wall to achieve the high-quality forming of cylindrical parts or inner ring reinforcement components. This technology enriches the plastic forming theory and widens the application field of plastic forming. In addition, the formed large-scale high-performance inner ring stiffened magnesium (Mg) components have been successfully verified in aerospace equipment, solves the problems of integral forming and severe deformation strengthening and toughening of large-scale inner ring stiffened components, and has a good prospect of popularization and application.
In this paper,Ti-Zr28-Cu15-Ni15(1#) and Ti-Zr21-Cu20-Ni15(2#) amorphous filler metals were prepared by rapidly-cooled equipment in order to join the TA15 titanium alloy honeycomb sandwich panel structures.The joint microstructure and tensile strength was investigated by means of SEM,EDS and XRD etc.The results indicated that both of the fillers perform good forming property.Compared with the conventional fillers,the quenching fillers have lower melting temperature and narrow melting temperature range.Filler metal 2# performs higher wettability and glass forming ability than filler metal 1# due to its high percent of eutectic composition.The tensile strength of the brazed joint reached 325MPa at 970℃ for 30min with filler metal 1#,while the tensile strength of the brazed joint reached 359MPa at 950℃ for 30min with filler metal 2#,and the mechanical stability of the joints is excellent.α+β lamellar structure formed in both joints brazed in the same condition,and smaller amount of Ti-Cu and Ti-Ni intermetallic compounds in the joints brazed with filler metal 2#.
Using binomial distribution, we have created a structure to describe Si 1-x Ge x substrate, so ion implantation into Ge and Si 1-x Ge x can be simulated based on Molecular dynamics method. ZBL potential is applied to describe interaction between implanted ion and target atoms. David Cai's electronic stopping power model is applied to calculate collision between implanted ion and electronics. The results of boron implantation into pure Ge and Si 1-x Ge x are compared with SIMS data. The phenomenon of fluence loss due to surface sputtering and backscattering is investigated. Factors affecting range profile and fluence loss including Ge fraction and implant tilt is also presented in this paper.This electronic document is a "live" template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.
To investigate the transport behaviour of fractured rocks (tightly compacted granular material) under loading/unloading, a dual permeability model was applied by means of numerical simulation. The numerical samples had a size of 80 × 80 mm2 and consisted of granular material with average grains of 1.6 × 1.6 mm2 in size. The grain boundaries were strongly bonded and the samples behaved like intact rock blocks mechanically, but the grain boundaries were permeable and provided the primary permeability for the matrix. Fractures might initiate and grow along the grain boundaries where the level of stress exceeded their strength. The fractures newly created and the pre-existing ones that were embedded within the samples might be much more permeable than the passive grain boundaries, and they would dominate the transport behaviour of the samples if a connected fracture network formed. By increasing fluid pressure (constant differential stress) and increasing differential stress (constant fluid pressure), two types of loading schemes were applied to the samples. As a result, connected fracture networks developed at a certain stress state. The evolution of fractures and fracture networks greatly altered the flow patterns; main flows were being concentrated within those continuously open fracture networks. On the other hand, the change in hydraulic conduits has led to a strong modification of the fluid pressure distribution. Under low effective mean stress (high fluid pressure), secondary percolation phenomena occurred in the loading plane because of the presence of a connected network of open fractures. In this case, the permeability in the loading plane and in the direction perpendicular to the plane increased greatly. Under high effective mean stress (highly differential stress and constant fluid pressure); however, such a secondary percolation threshold was unlikely to exist, although a connected network developed at a critical stress state. This was because most of those fractures created did not open under high effective mean stress, and the deformation was characterized by grain boundary sliding and isolated, dilational jogs at the intersections of grain boundaries. In this case, the permeability in the loading plane had a slight reduction caused by lack of continuously open fractures, but the permeability in the direction perpendicular to the loading plane increased sharply and became highly localized. The deformation and permeability of the samples were examined when subjected to cycling loads. The fluid pressure alternated between the hydrostatic fluid pressure and a higher fluid pressure (supra-hydrostatic) at which the samples became unstable. During the cycling loading the fractures opened and closed periodically, and the permeability increased and decreased correspondingly. When the fluid pressure decreased from a high level to a low level (loading) in a cycling load, the permeability and deformation of the samples did not totally return to the previous state, indicating a clear plastic deformation. After a number of cycling loads, the plastic deformation and permeability increased progressively, which suggests strong path-dependent behaviour. The overall permeability of the samples increased with increasing extensional strain. For the same extensional strain, the permeability was greater under a low effective mean stress than under a high effective mean stress, and greater during continuous loading than cyclic loading.
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