scholarly journals Texture Gradient in a Rectangular Extruded Al60Mg40 Metal Matrix Composite

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 167
Author(s):  
Soheil Sanamar ◽  
Heinz-Günter Brokmeier ◽  
Norbert Schell

By applying cold extrusion, an elemental metal powder composite Al60Mg40 was prepared. The texture gradient was measured over the cross-section of the extrusion profile using synchrotron radiation while the bulk texture was obtained by neutron diffraction. The aluminum phase shows a typical texture component of plane-strain deformation in the middle part of the sample and a uniaxial deformation texture at the surface. In the central region of the extruded bar, the (0002) Mg pole figure shows a split along the extrusion direction (±ED), which also has been observed in rare-earth containing magnesium alloys. These two poles twist towards the transverse direction on moving towards the surface of the extruded bar; one pole moves to +TD and the other one to −TD. The angle of twist increases towards the TD surface.

2005 ◽  
Vol 495-497 ◽  
pp. 821-826 ◽  
Author(s):  
Werner Skrotzki ◽  
N. Scheerbaum ◽  
C.G. Oertel ◽  
Heinz Günter Brokmeier ◽  
Satyam Suwas ◽  
...  

Silver of 3N purity was deformed at room temperature by equal channel angular pressing (ECAP) using three passes of route A. The global and local texture were investigated by neutron diffraction and high-energy synchrotron radiation, respectively. The texture is characterized by typical simple shear components of fcc metals which differently deviate from their ideal positions. Local texture measurements reveal that the intensity and inclination of the texture components with respect to the extrusion direction depend on the distance from the top of the extruded bar and change from pass to pass. Reasons for the texture gradient are discussed. The texture of silver is compared with that of copper having a higher stacking fault energy.


2020 ◽  
Author(s):  
Anastasia Kushnareva ◽  
Artem Moskalenko ◽  
Alexander Pasenko

<p>The Talas Range forms the northwest part of the Caledonides of the Northern Tian Shan. Based on differences in the structural style, metamorphism and sedimentary successions, three thrust sheets have been identified – the Uzunakhmat, Talas, and Kumyshtag thrust sheets. The Talas and Kumyshtag thrust sheets consist of Neoproterozoic-Ordovician terrigenous and carbonate rock units, whereas the Uzunakhmat thrust sheet consists of Neoproterozoic terrigenous rocks metamorphosed up to greenschist facies. The Uzunakhmat thrust sheet is separated from the Talas and Kumyshtag thrust sheets by the southwest-dipping Central Talas thrust (CTT). The dextral strike-slip Talas-Fergana Fault bounds the Uzunakhmat thrust sheet in the southwest. The main deformation events occurred in the Middle-Late Ordovician.</p><p>Structural and strain studies were done along profiles normal to the strike of folds and faults and located in the northwest and southeast parts of the Uzunakhmat thrust sheet. We also incorporate in our study structural profile in the central part of the Uzunakhmat thrust sheet, documented by Khudoley (1993) and Voytenko & Khudoley (2012).</p><p>The main strain indicators were detrital quartz grains in sandstones. Rf/φ and Normalized Fry methods were used to identify the amount of strain. Oblate ellipsoids predominate with Rxz values varying mostly from 1,6 to 2,4. Long axes of strain ellipsoids are sub-horizontal with the southeast to east-southeast trend. Similar trends have long axes of the anisotropy magnetic susceptibility ellipsoid being parallel to fold axes, cleavage-bedding intersection and mineral lineation as well as the trend of the major thrusts, including CTT.</p><p>The modern shape of the Uzunakhmat thrust sheet is similar to an elongated triangle, pinching out northwest and expanding southeast. Cross-section balancing corrected for the amount of strain shows along-strike decreasing of shortening in the southeast direction. Total shortening varies from 35% to 55% between sections located about 15 km from each other. Such significant variation in shortening corresponds to variation in structural style with much more tight folds and more numerous thrusts for cross-sections with a higher amount of shortening. However, the restored length of all cross-sections is quite similar pointing to the approximately rectangular initial shape of the Uzunakhmat thrust sheet. Our interpretation is that during the Caledonian tectonic events, the Uzunakhmat thrust sheet was displaced in the northwest direction with accompanied thrusting and folding of rock units within the thrust sheet. These deformations formed the modern shape of the thrust sheet in accordance with the amount of shortening detected by cross-section balancing. This interpretation also implies that modern erosion did not significantly affect shape of the Uzunakhmat thrust sheet formed after the Caledonian deformation.</p><p>Khudoley, A.K., 1993. Structural and strain analyses of the middle part of the Talassian Alatau ridge (Middle Asia, Kirgiystan). J. Struct. Geol. 6, 693–706.</p><p>Voytenko N.V., Khudoley A.K. Structural evolution of metamorphic rocks in the Talas Alatau, Tien Shan, Central Asia: Implication for early stages of the Talas-Ferghana Fault. // C. R. Geoscience. 2012. V. 344. P. 138–148.</p>


2020 ◽  
pp. 33-37
Author(s):  
S. M. Belskiy ◽  
◽  
A. N. Shkarin ◽  
V. A. Pimenov ◽  
◽  
...  

The geometric parameters describing the features of the crosssectional profile of a hot-rolled strips do not give a complete picture of the flatness acquired by the cold-rolled strips rolled from these strips. An additional analysis, the results of which are presented in Message 1, showed that there are four characteristic classes of cross-sectional profiles of hot rolled strips that have a significant effect on the shape of the strips during cold rolling, three of which negatively affect the flatness of the cold rolled strips. The cross-sectional profiles of hot-rolled strips with a concave middle part and / or marginal thickenings lead to the appearance of edge waviness, peak-like cross-sectional profiles cause central warping. Therefore, the actual task is to determine the factual shape of cross-sectional profile. 6th order polynomials were used to digitalize and parameterize hot-rolled profile. As a result, we developed analytic function of the transverse profile, which keeps important information about its near-edge areas and features in the middle part. To assign a specific crosssectional profile of a hot-rolled strip to one of four characteristic classes of cross-sections, mathematical software was developed, called a classifier, and implemented with the programming environment R. To classify the profiles of the hot-rolled cross-section according to characteristic classes, a linear discriminant method was used as a machine learning method analysis. The result is an adequate mathematical model for recognizing the shape of the cross-sectional profile. The study was carried out with the financial support of the Russian Foundation for Basic Research within the framework of scientific project No. 19-38-90257.


1997 ◽  
Vol 127 (3-4) ◽  
pp. 243-252 ◽  
Author(s):  
S. K�dela ◽  
R. Rennekamp ◽  
S. Baunack ◽  
V. Gergely ◽  
S. Oswald ◽  
...  

2016 ◽  
Vol 879 ◽  
pp. 2014-2019
Author(s):  
Osamu Umezawa ◽  
Norimitsu Koga

Unalloyed titanium was rolled with 20% reduction in each pass at 293 K using a cross rolling mill, where the upper and lower rolling axes were skewed each other at an angle of 0, 5 or 10 degree with parallel position. Multi-pass flat-rolling was carried out without any lubricants up to the true strain of 1, where two kinds of rolling directions such as tandem (uni-direction for all passes) and reverse (opposite direction in every passes) were adopted. The strain of specimens was increased proportionally as higher passes regardless of the rolling conditions. The transverse direction (TD) split deformation texture in titanium was generally developed under the cross angle of 0 degree. In the present strips of tandem, a main orientation was identified as (-12-18)[10-10]. In the case of tandem with the cross angle of 5 degree, a fiber texture was developed along (-12-18). That is the reason why a rotation in the rolling direction (RD) was overlapped. In the case of reverse with the cross angle of 5 degree, the main orientation was separated into [10-10] and [2-311] that were corresponded to TD and RD splits, respectively.


Energetika ◽  
2016 ◽  
Vol 62 (1-2) ◽  
Author(s):  
Paulius Vilkinis ◽  
Mantas Valantinavičius ◽  
Nerijus Pedišius

A study of fluid flow in structured channels plays an important role in solving most fluid dynamics problems. The  knowledge of the  flow structure in separate cavities can be used to intensify mixing in microreactors and microelectrochemical systems (MEMS) as well as to increase heat transfer in heat sinks. Besides, knowledge about fluid flow in micro cavities could be useful to mitigate the symptoms of aneurysms. In this study, a 2D micro-particle image velocimetry (µPIV) system was used to investigate water flow in an open-type microcavity located in a straight, square cross-section (0.5  ×  0.5  mm2) microchannel. Two identical micro cavities of the  same cross-section as the  main channel and the  depth of 1  mm are oppositely located in the middle part of the channel. Because of symmetry, the flow structure of the primary vortex was investigated in only one cavity. Measurements were carried out in different planes over the entire height of the cavity at Reynolds number in the range from 100 to 3000. The flow in the channel was stationary and pulsating. Results indicate that flow in the cavity is three-dimensional. This is confirmed by velocity profile shape changes in its different transversal planes. In addition, it is determined that flow structure in the  cavity depends on flow regime and flow pulsation characteristics. Velocity distribution shows that in the transverse direction there is the minimum velocity zone corresponding to the centre of the primary vortex generated by the channel flow, also the same zone is observed along the cavity in its axial plane. At low Re, such velocity distribution occurs in pulsating flow earlier than in the case of stationary flow. With increasing Re, velocity distribution in pulsating flow flattens out also more. It means that disturbed flow in the channel accelerates the formation of a stable flow structure in the cavity.


Metal matrix composite is considered in various engineering fields like Automobile, medical, electronics aerospace, marine, recreational sectors, of which Aluminum metal matrix composite is considered mostly because of its high strength to weight ratio, easy of fabrication, corrosion resistance, good aesthetic appearance and high resistance to wear etc. This paper concentrates on the effect of secondary processing (Cold Extrusion) on mechanical and wear properties of Al6063 reinforced with SiC, Al2O3 and CeO2 particles. Here composite systems prepared by varying reinforcement from 0% to 8% in steps of 2%. Stir casting route adopted for casting composite systems after casting the composite is made to pass through extrusion process with an extrusion ratio of 1.93 with a total strain of 1.45. All composite systems tested for mechanical properties as per ASTM and ISO standard. Wear test was conducted on pin on disc setup for different loads, reinforcement, sliding distance and sliding speed. Results reveals that due increase in reinforcement the mechanical properties have improved further improvement observed when subjected to extrusion process, similar observation was made for wear studies which conclude the wear rate is improved for extruded composite as compared to cast composite systems observed by various researchers.


2005 ◽  
Vol 495-497 ◽  
pp. 1633-1638 ◽  
Author(s):  
Chris H.J. Davies ◽  
Sang Bong Yi ◽  
Jan Bohlen ◽  
Karl Ulrich Kainer ◽  
Heinz Günter Brokmeier

The crystallographic response to deformation – texture evolution, internal elastic strain, and twin evolution – was measured for three load/orientation variants for AZ31 magnesium alloy extrudate tested in-situ in a synchrotron beamline. Specimens were loaded in tension parallel to the extrudate transverse direction, in compression along the same axis, and in compression parallel to the extrudate normal direction. The crystallographic responses are correlated with the mechanical behaviour of the extrudate.


2011 ◽  
Vol 194-196 ◽  
pp. 1437-1441 ◽  
Author(s):  
Chun Lin He ◽  
Jian Ming Wang ◽  
Qing Kui Cai

The texture development was investigated in the extruded Al and Al metal matrix composites (MMCs) reinforced with SiC particles of different sizes and volume fractions. During extrusion, both the unreinforced Al and the MMCs develop a strong fiber texture with two components: <111> and <100>. When SiC is introduced into aluminum, the main component of texture is not modified, but the intensity of the component evolves with the volume fraction and average size of SiC particles. For the MMCs reinforced with 3.5μm SiC particles, the texture intensity of the Al matrix tends to decrease as the SiC volume fraction increases, and it is lower than that in the unreinforced Al. However, for the MMCs reinforced with 25 nm and 150 nm SiC particles, the texture intensity of the Al matrix is higher than that in the unreinforced matrix, and it increases with increasing the SiC volume fraction. It is found that superfine particles may introduce some new component into the deformation texture, and the texture intensity increases as the SiC particle size decreases.


Author(s):  
Y Tang ◽  
S D Zhao ◽  
Z W Wang

In this article, novel precision bar cropping machinery, with a modified rotary swaging machine, which has been extended by the addition of a stroke adjuster, was designed and built. By adjusting the strike frequency and the radial displacement, a crack can be made to propagate quickly and regularly, leading to a final regular separation of the bar. Precision cropping experiments on several metal bars were conducted, which can be directly used in the subsequent process, such as cold-extrusion and cold-forging and so on because of the high-quality cross-section, high geometric and weight precision using this cropping device.


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