Understanding the superior mechanical properties of Mg-3Al-Zn alloy sheets:Role of multi-type unique textures

Mg-3Al-1Zn(AZ31)sheets were produced by transverse gradient extrusion(TGE)process.The flow behavior and dynamic recrystallization during extrusion were systematically analyzed.The microstructures,textures,and mechanical behavior of extruded AZ31 sheet were also analyzed and compared with conventional extruded(CE)sheet.The results showed that fine grain structure and multi-type unique textures were formed in TGE sheet because of the generation of extra flow velocity along transverse direction(TD)and flow velocity gradient along extrusion direction(ED)during extrusion.The basal poles gradually deviated away normal direction(ND)from edge to center of the TGE sheet along TD,and the largest inclination angle at center region reached around 65°.Furthermore,the basal poles inclined from ED to TD 40°-63°,except for the center region of TGE sheet.The TGE sheet presented higher ductility and strain hardening exponent(n-value),but lower yield strength and Lankford value(r-value)in comparison with the CE sheet.Both the basal<a>slip and tensile twins were easy to be activated during deformation,and the largest elongation of 41%and the lowest yield strength of 86.5 MPa were obtained for the ED-center sample in the TGE sheet.

Correlation of image textures of a polarization feature parameter and the microstructures of liver fibrosis tissues

Mueller matrix imaging is emerging for the quantitative characterization of pathological microstructures and is especially sensitive to fibrous structures.Liver fibrosis is a characteristic of many types of chronic liver diseases.The clinical diagnosis of liver fibrosis requires time-consuming multiple staining processes that specifically target on fibrous structures.The staining proficiency of technicians and the subjective visualization of pathologists may bring inconsistency to clinical diagnosis.Mueller matrix imaging can reduce the multiple staining processes and provide quantitative diagnostic indicators to characterize liver fibrosis tissues.In this study,a fibersensitive polarization feature parameter(PFP)was derived through the forward sequential feature selection(SFS)and linear discriminant analysis(LDA)to target on the identification of fibrous structures.Then,the Pearson correlation coeffcients and the statistical T-tests between the fiber-sensitive PFP image textures and the liver fibrosis tissues were calculated.The results show the gray level run length matrix(GLRLM)-based run entropy that measures the heterogeneity of the PFP image was most correlated to the changes of liver fibrosis tissues at four stages with a Pearson correlation of 0.6919.The results also indicate the highest Pearson correlation of 0.9996 was achieved through the linear regression predictions of the combination of the PFP image textures.This study demonstrates the potential of deriving a fiber-sensitive PFP to reduce the multiple staining process and provide textures-based quantitative diagnostic indicators for the staging of liver fibrosis.

Three-Point Bending Test and Crack Detection by Acoustic Emission on Different Spring Steel Wires with Different Crystallographic Textures

In the production of compression springs,high forming velocities and grades of deformation during winding and setting may induce cracks that can lead to failure causing risks of an accident and damage.The AE(acoustic emission)technology,a non-destructive monitoring method,can detect acoustic signals reflected from cracks.To establish this method in the production of technical springs,it was necessary,to find out whether the AE signal is influenced by material properties,phase fractions distribution from tempered martensite,retained austenite,and microstructure including crystallographic texture.In addition,it was investigated to what extent the detected AE signal can be useful to separate between an actual crack and other material responses.Within an in-situ three-point bending test with the AE technology,macro-and micro-crack-typical AE signals were detected for five different spring steel wires(SH,VDSiCr,and FDSiCr according to EN-10270-1 and EN-10270-2).The relative energy related to the initiation,propagation,and growth of cracks caused by mechanical stress was measured using a piezoelectric sensor.If a crack AE signal appeared for the first time,the bending tests were stopped immediately.The results show that the frequency spectrum combined with the intensity of the acoustic signals generated during crack growth depends on the material properties and the crystallographic texture.Furthermore,it could be shown that it is possible to differentiate between micro-crack-typical AE signals and other signals that result from different material responses.

Highly c-axis Oriented YBCO Thin Films Deposited on Cold Rolling Ag Substrates and Textures of Cold-Rolling and Recrystallization in Ag

By selecting flexible polycrystalline Ag as the metallic substrates, highly c axis (001) textured YBCO thin films were fabricated by using a modified magnetron sputtering equipment which can accomplish dynamic deposition and in-situ anneal treatment. The textures of Ag substrates have important effects on forming YBCO films with high critical current densities. Research on the textures of cold rolling Ag at different deformation degrees and recrystallization textures of Ag at different temperatures shows that in plane alignment of YBCO films is difficult to be obtained directly on cold rolling Ag substrates, because of the texture change of Ag during deposition heating of substrates and the strong dependence of J c of YBCO films on grain boundary misorientation angle of substrates. The recrystallization textures with cube (001) and rotated cube (001) in Ag were obtained. Experiments offer a possible prospect for the further research of fabricating sharp biaxially texture in Ag and the following deposition of high J c YBCO films directly on it.

Evolution of recrystallization textures in high voltage aluminum capacitor foils

The evolution of recrystallization textures in high voltage aluminum capacitor foils which are produced with a high level of cold reduction was tracked by analysis of microstructure and crystallographic texture. The results show that the deformation textures are mainly composed of S orientation, Cu orientation and a little B s orientation. During the low temperature stages of final annealing, the iron precipitates first along the sub grain boundaries, and the Fe concentration in the matrix becomes low. Then, the cube grains nucleate preferably into the sub grains. At high temperature stages, the cube nuclei can grow preferably because of their 40°<111> orientation relationship to the S orientation, the main component of the rolling texture. Finally, the cube texture is sharply strong and the R orientation is very weak in the foils.

The relationship between dolomite textures and their formation temperature: a case study from the Permian-Triassic of the Sichuan Basin and the Lower Paleozoic of the Tarim Basin

Study of dolomite texture can contribute to understanding the process of dolomitization.This research reports textures and homogenization temperatures of dolomites from the Permian-Triassic strata in the Sichuan Basin and the Lower Paleozoic strata in the Tarim Basin,which provided insights into relationships between dolomite textures and their formation temperatures.Our results are summarized as follows：1） dolomites with well-preserved texture indicate low dolomitization temperature.However,in certain diagenetic environments,the hydrothermal dolomitization may completely or partially preserve the original texture of dolomites.2） The formation temperatures of non-planar dolomites are always higher than those of planar dolomites.3） The formation temperatures of dolomite cements are generally higher than those of replacive dolomites.4） Although the formation temperatures of saddle dolomite cements have a wide range,they show higher values than those of the planar subhedral to euhedral dolomite cements.Thus,saddle dolomites could generally be an indicator of high precipitation temperature.5） The fluid Mg/Ca ratio is another element controlling dolomite morphology.Micritic dolomites,which precipitate from hypersaline fluids with a high Mg/Ca ratio in a subaerial environment could also have features of non-planar anhedral crystal shape because of rapid nucleation and crystallization during dolomitization.

Formation mechanisms of recrystallization textures in aluminum sheets based on theories of oriented nucleation and oriented growth

The recrystallization textures in 95%rolled aluminum sheets with different purities and initial textures were investigated.The effects of recovery levels and the dragging effects induced by impurities on the effective driving force and corresponding behaviors of oriented nucleation and oriented growth during annealing were analyzed.The oriented nucleation is a common behavior in the initial stage of primary recrystallization if the effective driving force in deformed matrix is not too high to reduce the necessity of nucleation period.Oriented growth might appear if the temperature is not too high and the grains,of which the misorientation to matrix is about 40°〈111〉,have enough time and space to expand growth advantages,while certain reduction of effective driving force is also necessary.The recrystallization textures could be changed by controlling initial textures and effective driving forces which can be regulated by recovery levels and dragging effects.

The effect of extrusion conditions on the properties and textures of AZ31B alloy

The effect of extrusion conditions on the tensile properties and texture of AZ31B alloy has been investigated by means of optical microscopy(OM),scanning electron microscopy(SEM),electron backscattered diffraction(EBSD)and tensile tests.It is found that the ultimate tensile strength(UTS),the yield strength(YS)and elongation(EN)of the extruded AZ31B alloy are more significantly influenced by extrusion velocities in contrast with temperature.Although the extrusion conditions are different,the {1102}<0101> texture is the chief texture in the AZ31B after extrusion.Moreover,the extrusion textures become scattered with increasing the temperatures at the same extrusion velocity.As the extrusion velocity is raised at the same temperature,the orientation density of textures increases and the separated textures become relatively concentrated.This leads to the changes of tensile properties at different extrusion conditions.©2017 Production and hosting by Elsevier B.V.on behalf of Chongqing University.

Bulk and local textures of pure magnesium processed by rotary swaging

Rotary swaging processing on commercial as-cast pure Mg has been carried out. Bulk texture variation with the processing passes was investigated using large gauge volume by neutron diffraction, of which results showed a combination of different components such as {00.2} basal fibre and two weak {10.0} and {11.0} fibres. Asymmetric distribution of the basal fibre around swaging direction was observed and being related to the processing parameters. Texture gradient analysis by synchrotron radiation demonstrates a non-uniform deformation of the RS processed pure Mg from surface to the centre.

Effect of concurrent precipitation on recrystallization textures in commercial Al-Mn alloys

The effect of concurrent precipitation on recrystallization textures in AA 3003 aluminum alloys was investigated using X-ray diffraction and electron backscattering diffraction（EBSD） analyses. A weak recrystallization texture was observed in the AA 3003 alloy annealed at 783 K due to the high annealing temperature. Under the same conditions, extremely high P {011 } （ 111 ） recrystallization textures were detected in the AA 3003 alloy added with 0. 39% Sc. Based on the EBSD results, no intensely preferential orientation nucleation of recrystallization grains was observed in the early stage of recrystallizafion for both alloys. However, concurrent precipitation strongly retarded the growth of recrystallization grains, except for P nucleation sites, thereby conferring an apparent initial growth advantage for P nucleation sites compared with other nucleation sites. Therefore, a sharp P {011 } 〈 111 〉 texture appeared in concurrently precipitated AA 3003 alloys.

Ore Mineral Textures of Late Cretaceous Volcanogenic Massive Sulfide Deposits (VMS) of Turkey: Proposed Paragenetic Sequence

Most of the massive sulfide deposits (VMS) occurring from Precambrian to Cenozoic throughout the world has been subsequently metamorphosed at various grades. Thus, all the original textures have been either completely destroyed or strongly modified. However, there are a very few examples, rather younger deposits such as late Cretaceous Turkish VMS deposits and Miocene Kuroko deposits of Japan in which representative and original ore textures are preserved. The Turkish massive sulfide deposits are mainly Cu-Zn-Pb-type and entirely hosted by Late Cretaceous felsic volcanic rocks within a paleoarc geotectonic setting.

Surface textures of quartz grains from a core at the Prydz Bay,Antarctica

In this paper, shapes and surface textures of quartz grains in 13 layers of a core (NP95 1) collected from a continental slope at the Antarctic Prydz Bay were quantitatively and statistically analyzed. The quartz grain surfaces exhibit the characteristics caused by intense glaciation and a weaker chemical solution precipitation, indicating the sediments are mainly morainic debris under a low energy marine environment. The obtained quantitatively statistical results of the assemblages of surface textures caused by the chemical solution precipitation are well correlated to the analytical results of micropaleontologic analysis and can be used to better explain the changes of sedimentary environment and paleoclimate occurred in the marine zone concerned.

Method of ameliorating the lubrication and friction performance of an engine based on different microtextures

A design of different microtextures on the surface of the crankpin bearing(CB)is proposed to ameliorate the lubrication and friction performance(LFP)of engines.On the basis of the CB s hydrodynamic lubrication model,the bearing surface of CB using different microtextures,such as wedge-shaped textures(WSTs),square textures(STs),circular textures(CTs),and combined square-circular textures(CSCTs),is simulated and assessed under various external loads of the CB at an engine speed of 2000 r/min.The pressure of the oil film,the frictional force,the force of the solid asperity contact,and the friction coefficient of the CB are used as objective functions.Results indicate that the bearing surface designed by the STs remarkably improves the CB s LFP in comparison with other structures of WSTs,CTs,and CSCTs.Particularly,the average values of the frictional force,solid asperity contact,and friction coefficient of the CB using the STs are greatly reduced by 28.5%,14.5%,and 33.2%and by 34.4%,26.3%,and 43.6%in comparison with the optimized CB dimensions and CTs,respectively.Therefore,the application of the STs on the CB surfaces can enhance the LFP of engines.

创造无限——专业级的纹理制作软件Infinity Textures

这一段时期．笔者一直在从事虚拟现实．以及游戏场景的开发制作。在贴图纹理的处理上．应用于网络的虚拟现实技术，像vrml三维场景要求贴图尽可能的小．以减少浏览这下载的时间，一个重要的技巧就是利用四方连续的图片纹理．比如，一面高楼的整个贴图．当然不会是整张的图片，而仅是一张小门窗的四方连续图片．一伸展开。

Influence of Microstructures and Textures on the Torsional Behavior of Pearlitic Wires

The microstructure, texture characteristics and torsion ability of two kinds of steel wires were investigated. The eutectoid steel wires were produced by hot and cold drawing with severe deformation. The torsinability of steel wires was measured under two cases, i.e. there exists either fiber texture or circular texture. The results showed that the torsional behavior of the steel wires was affected by their textures and microstructures. The {110}<110> circular texture weakened the torsion ability of the wires. The torsion fracture behavior of {110}<110> texture wires is related to the fact that only two slip systems were activated under simple shear strain deformation.

High- and Ultrahigh-pressure Metamorphism and Retrogressive Textures of Gneiss in the Donghai Area——Evidence from gneisses in drillhole ZK2304

In the gneisses from the drillhole ZK2304 of the Donghai area, there have been preserved high- and ultrahigh-pressure metamorphic mineral assemblages, a series of complicated retrogressive textures and relevant metamorphic reactions. In addition to garnet, jadeititic-clinopyroxene and rutile, other peak stage (M2) minerals in some gneisses include phengite, aragonite and coesite or quartz pseudomorphs after coesite. The typical peak-stage mineral assemblages in gneisses are characterized by garnet + jadeitic-clinopyroxene + rutile + coesite, garnet + jadeitic-clinopyroxene + phengite + rutile ± coesite and garnet + jadeitic-clinopyroxene + aragonite + rutile ± coesite. The grossular content (Gro) in garnet is high and may reach 50. 1 mol%. The SiO2 content of phengite ranges from 54.37% to 54.84% with 3.54-3.57 p.f.u. Quartz pseudomorphs after coesite occur as inclusions in garnet.The gneisses of the Donghai area have been subjected to multistage recrystallization and exhibit a closewise P-T evolutional path characterized by the near-isothermal decompression. The inclusion assemblage (Hb+Ep+Bi+Pl+Qz) within garnet and other minerals has recorded a pre-peak stage (Mi) epidote amphibole fades metamorphic event. High- and ultrahigh-pressure peak metamorphism (M2) took place at T=750-860℃ and P>2.7 GPa. The symplectitic assemblages after garnet, jadeitic-clinopyroxene and rutile imply a near-isothermal decompression metamorphism (M3, M4) during the rapid exhumation. Several lines of evidence of petrography and metamorphic reactions indicate that both gneisses and eclogites have experienced ultrahigh-pressure metamorphism in the Donghai area. This research may be of great significance for an in-depth study of the metamorphism and tectonic evolution in the Su-Lu ultrahigh-pressure metamorphic belt.

Evaluation of surface textures and skid resistance of pervious concrete pavement

Surface textures had long been recognized as primary factors to provide the skid resistance on pavements; however, no measurement of skid resistance on pervious concrete pavement with various surface texture parameters had been made. Fractal geometry was introduced in the present work to accurately simulate transect contour curves of pervious concrete specimens through fractal interpolation. It is proved that its fractal dimension (D) can be adopted to measure the skid resistance on pervious concrete pavement, overcoming the shortcomings of both macrotexture depth (DT ) and British portable pendulum number (NBP). Combined with Fujikawa-Koike tire/road contact model, the optimization method of all surface textures was recommended for designing and constructing excellently skid-resistant and noise-absorptive pervious concrete pavement. In addition, evaluating of the abrasion process and attenuation of the surface textures on concrete pavement slabs was also the focus of this work based on accelerated abrasion test. Results show that the surface textures on pervious concrete pavement slabs is extremely durable, compared to those on conventional grooved or exposed aggregate concrete pavement slabs.

Microstructure,Textures and Deformation Behaviors of Fine-grained Magnesium Alloy AZ31

Channel die compression and initial textures are used to activate different deformation mechanisms in a fine-grained magnesium alloy AZ31. The σ-ε curves, microstructures and, particularly, textures are analyzed to reveal different deformation mechanisms and to compare with those of coarse grained samples. Dominant double-prismatic slip, {1012} twinning and basal slip are detected in three types of samples, respectively, which is similar to those of coarse grained samples. The detrimental effect of shear band formation or {1011} twinning is limited in fine grained microstructure. In addition to the higher flow stress at low temperature an early decrease in flow stress at higher temperature is also found in fine-grained samples in comparison with their coarse-grained counterparts. This softening is ascribed to the early dynamic recrystallization or grain boundary glide.

Experimental Study and Finite Element Polycrystal Model Simulation of the Cold Rolling Textures in a Powder Metallurgy Processed Pure Aluminum Plate

Ingot metallurgy (IM) aluminum has long been the subject and attracted the attention of many metallurgists and textural researchers of materials. Due to the introduction of large amounts of ex situ interfaces, however, the textures in powder metallurgy (PM) processed aluminum has been rarely reported. In this article, a pure aluminum plate was prepared via PM route. The starting billet was first produced with uni-axially cold compaction and flat hot-extrusion and then followed by cold rolling processes. The hot-extruded and cold rolling deformation textures of the pure PM aluminum at 50%, 80% and 90% cold rolling reductions were studied by orientation distribution functions (ODFs) analysis. The finite element polycrystal model (FEPM) was finally utilized to simulate the cold rolling textural evolution at various stages of cold rolling. In FEPM simulation, the initial hot-extruded textures were taken into account as inputs. The results showed that typical β-fiber texture formed in pure PM aluminum with the cold rolling reduction increased till 80%, and there was not much change after excessive cold rolling deformation. Homogeneous slip is not the only deformation mode in PM processed pure aluminum plate at over 80% cold rolling reduction. The experimental results were qualitatively in good agreement with the simulated ones.

Finite element simulation of influences of grain interaction on rolling textures of fcc metals

A rate dependent crystal plasticity constitutive model considering self and latent hardening in finite element analysis was developed to simulate rolling textures of pure aluminum. By changing the assignment of orientations to finite elements, i.e. assigning the same set of orientations to all elements or different orientations to different elements, the influences of grain interaction on the formation of rolling textures were numerically simulated with this kind of crystal plasticity finite element model. The simulation results reveal that the grains without considering grain interaction rotate faster than those considering grain interaction, and the rotation of grain boundary is slowed down due to the grain interaction. For a good simulation more elements should be assigned to one grain, in which the effects of both the boundary and interior parts of grain contribute to the formation of rolling textures.