Papers by Keyword: Texture

Abstract: The utilisation of friction-induced solid-state recycling, methodically adapted to the CoNform process, facilitates the continuous production of semi-finished products. The material intended for recycling is conveyed continuously via a rotating wheel. The volume flow is influenced by fixed surfaces, deflections, and constrictions, thereby creating an asymmetrical flow profile. In order to effect a change in the mechanical properties of the semi-finished product, the material fed into the process can be modified. This enables the amalgamation of two alloys or the direct transition between them. The inhomogeneous flow conditions present within the tool give rise to the mixing of materials, thereby creating a graded multi-material zone. The multi-material zone was divided into different areas and traced back to the process conditions. Within the transitions, the connections between the alloys were examined, as well as the influence on the boundary layer. Material properties were determined for the individual areas and located along the length of the profile.

Abstract: The usage of laterite is highly in the demand in all aspect of project. Assessing the index properties of lateritic soil from quarries in Kuje Area Council of FCT which can be used for construction needs. The characteristics of the laterite such as In-situ quality of laterite, color, Physical appearance, structure, and strength were examined by assessment. Quarried lateritic gravel from different quarry depths was enumerated for some index characteristics. Mechanical assessment of laterite from the location was performed to determine the amounts of the various characteristics, textures, and structures that were analysed by taking samples. The general characteristic including mechanical properties of laterite were however seen to be dependent on the soil in-situ profile characteristics, color, and general properties. The characteristics of laterite discovered to different totally concerning the area and depth of the quarry. There was an inquisition to understand the connection in between physical characteristics, and the general strength of the laterite. The results of the analyses are Atterberg Limit with Liquid limit 58% & 68% Plastic limits with 32% & 46% and plasticity index with 26% & 22%, other test are sieve analysis, with AASHTO A-7-5(5) & A-7-5(2) and Compaction test with O.M.C of 20.4% & 24.6%, M.D.D with 1.630 & 1.560, Soil specific gravity test with average 2.71 while permeability test has average 2.71 permeability. It is discovered that the samples needed to be stabilize so as to have strength to withstand imposed pressure or load after stabilization.

Abstract: Austenitic stainless steels (ASSs) are characteristic with a combination of good mechanical and corrosion properties. Therefore, they are used in the primary circuits of nuclear power plants. Under the influence of a corrosive environment containing chloride ions and mechanical loading, the phenomenon of stress corrosion cracking occurs in ASSs. SCC can also be initiated by the surface condition of ASSs. Machining is usually the last stage of production, during which a significant deformed zone with high residual tensile stresses can be created, which can accelerate the initiation of stress corrosion cracking. Research is focused on analyzing the influence of final turning on microstructural changes of the surface-machined layer caused by various turning parameters (e.g.: cutting speed, feed, depth of cut, cutting tool geometry). No significant microstructure changes were observed between the samples by light microscopy, so we focused on transmission electron microscopy (TEM) on thin lamellas prepared using the focus ion beam (FIB) technique. TEM observation confirmed the presence of a deformed zone and a passivation layer. In the case of the sample that was turned with a higher feed and cutting speed, the passivation layer was discontinuous. Such a microstructural change can significantly affect the corrosion resistance of ASS.

Abstract: The mechanical behaviour of materials is influenced by processing and thermomechanical exposure. In safety-sensitive industries there is a need to make predictions on the envelope of safe use beyond proven constitutive equations. Microstructural simulations, such as crystal plasticity modelling, can model features like grain size, morphology and texture. However, they are computationally demanding and it can be hard to translate measured microstructures into meaningful or representative statistical distributions. Surrogate models incorporate machine learning regression and statistical methods to emulate the response of a complex model. As they are much faster, they can model the response over a wide range of material parameters, permitting sensitivity analysis and uncertainty quantification. Preferred orientation (texture) can be challenging to incorporate into surrogate models as accurate representations can require a lot of parameters. In this study, reduced-order representations of crystallographic texture are presented to represent the bulk response of a polycrystal volume element. These representations are used as inputs to a gaussian process regression (GPR) model that is used to predict the macroscopic stress-strain response of a polycrystal for different crystallographic textures. The GPR acts as a surrogate model of the underlying crystal plasticity model and allows an inherent quantification of the model epistemic uncertainty and the uncertainty related to unobserved effects not captured by the texture parameterization. Incorporation of the surrogate model into finite element coding will be used as an application of the method.

Abstract: The stretch flangeability of ferritic steel grade with tensile strength ≥1 GPa in hole expansion tests can be significantly improved by using the wire electrical discharge machining (W-EDM) process for hole-making instead of conventional punching tools. This improvement is attributed to the notably enhanced cut edge quality of the machined holes. In this study, the average hole expansion ratio (HER) of a novel 0.1C-0.3V-0.25Mo-0.08Ti-0.08Nb steel increased from 24% to 91% when W-EDM was used in hole preparation. A comparison between the fractured surfaces of punched and W-EDM-machined holes after HER testing revealed different failure mechanisms in the steel sheet. At the onset of cracking, fractures in the W-EDM specimens exhibited ductile behavior, whereas quasi-cleavage fracture was observed in the punched specimens. Based on texture measurements and metallographic investigations, it was concluded that reducing the intensity of the adverse shear texture component {112}<111> near the steel sheet surface and eliminating microstructural constituent variations improved the stretch flangeability of the Ti-Mo-V-Nb steel in both hole-making processes.

Abstract: Pectin is a water-soluble fiber that can increase the fiber content of cookies. The pectin used comes from cocoa pod husk extract which was previously only used as animal feed and became waste. This research aims to utilize the content of cocoa pod husks in the form of pectin as a food additive applied to cookies. This research uses quantitative analysis with the help of SPSS on the physical and chemical properties of cookies and their digestibility. Extraction was carried out with 5% (w/v) citric acid solvent for 5 hours at a temperature of 95°C. The extract obtained was analyzed using FTIR and the spectrum was compared with pure pectin used to IPPA (International Pectin Producer Association). Cocoa pod husk pectin extract has the same functional groups as pure pectin. The product, cookies with pectin substitution were tested for physical properties (color, texture), chemical properties (water content, crude fiber content) and digestibility. This study obtained results that the water content, color, texture, crude fiber content, and digestibility of cookies with pectin substitution were different from cookies without pectin. Pectin substitution in cookies was varied at 1, 4 and 7% (w/w) then compared with the control. The effect of pectin is known from the highest water content (6.01%), hard texture (79.57 g/mm), the highest crude fiber content (60.39%) and decreased digestibility (15.44 g/100 mg) at a variation of 7%. Pectin did not affect the color of cookies with no significant differences shown.

Abstract: Most forming oils have changed to chloride-free oil containing no chloride additives to protect environments regarding as the big issue of sustainable manufacturing. Several high-performance oil without chloride and die coating has been developed recently. In this study, the effect of micro-dimples on a die formed by a cutting machine or a laser device was tried to use chloride-free oil for ironing of stainless steel. The heavy galling occurred during ironing of stainless steel when the normal die without micro-dimples is used under a condition lubricated with chloride-free oil. The micro-dimples formed by the cutting machine only promoted galling because a large amount of burr remained around the dimples. The micro-dimples formed by the ultrashort pulse laser prevent from galling. The dimples have a smooth and mild profile on the die. The coverage area ratio of micro-dimples larger than 20% is needed for better ironing. A zigzag arrangement of the dimples uses the oil efficiently for well lubrication because galling occurs at the no dimples line between two rows of dimples if the dimples are neatly arranged parallel to the ironing direction.

Abstract: Shot-peening (SP) is one of the severe surface plastic deformation (SSPD) processing techniques. Due to large plastic strain by the SP, the SP for metallic materials forms crystallographic texture on the peened surface. Since the crystallographic texture formed by the SP depends on the dislocation slip, it can be expected that this texture is affected by stacking fault energy (SFE) of the materials. However, effects of the SFE on the crystallographic texture formed on the peened surface by the SP is not clear. In this study, crystallographic textures of pure Al (higher SFE) and Al-10 mass%Mg alloy (lower SFE) formed by the SP are investigated. When the pure Al is SPed, {001}+{111} double fiber texture with the <001> and <111> directions parallel to the plane normal direction of the peened surface is obtained. On the other hand, in the case of Al-10 mass%Mg alloy with the SFE close to the pure Cu, {110} fiber texture is formed as well as the pure Cu. Therefore, it is found that the crystallographic texture formed by the SP is influenced by the SFE.

Abstract: Laser beam welding is still the focus of research all over the world since new laser sources with more brilliance, higher power, or higher efficiency are being developed. High brilliance leads to thinner fibers when solid-state lasers are used. For welding applications, a thin beam, respective a small focus spot is recommended for low heat input resulting in less deformation. The edge preparation of the welding pieces must be as accurate as possible, and a zero gap is recommended. In earlier research, it was shown, that the gap bridging capacity could be enhanced by the wobbling of small focus spots, as well as refining the grain size in the weld zone by decreasing the focus diameter. Inventions in the optics, like the beam splitting into a core and a ring part, avoid the use of a scanner and can lead to better gap bridging. Nevertheless, the use of a brilliant beam, resulting in a small focus in combination with high power can result in very high welding velocities, just limited by the used machinery. In the present study, a disk laser with 4 kW maximum power and 100 μm focus spot was used to weld 2 mm thick magnesium AZ31 sheets at speeds up to 20 m/min. As expected, the seam width becomes smaller with raising velocity, and some underfill and access material occurred on the surface and the root of the welded sheets. Surprisingly, the texture of the weld seam changed from random at low velocity to a more pronounced texture at high speed with respect to the basal texture of the plate base material. This influences the mechanical behavior, namely the strain to fracture, of the welded joints positively. The high-speed weldments are compared to state-of-the-art weldments of magnesium AZ31, in terms of mechanical strength and elongation to fracture, based on the texture analysis.

Abstract: The design process of street furniture nowadays focuses on aspects that go beyond functionality. In this type of product, total aesthetic integration with the space is sought in order to minimise aesthetic pollution. People's quality of life is directly related to the environmental, visual and sound impact of street furniture. Hence the search for sustainability through materials and finishes based on biophilic design. In the context of recycled materials, one branch of research focuses on the search for applications such as street furniture. In turn, 3D printing technology makes it possible to manufacture customised products and use recycled materials. This work focuses on the creation of organic textures for the creation of street furniture printed with recycled materials. The aim is to analyse the state of the art in this field and propose a series of textures and reliefs based on organic shapes, their manufacture by additive manufacturing of fused material (FFF) and their metrological study of the manufactured pieces with respect to the models created by computer-aided design.