Commercial Purity Aluminum Research Articles

In-situ study of the effect of strain path change on dislocation boundary evolution in commercial purity aluminum

An in-situ study of the effect of strain-path change on deformation microstructure and slip activity has been investigated using samples of commercially pure aluminum. Changes in dislocation boundary arrangements and crystal lattice rotations were tracked using CMOS-based electron backscattered diffraction (EBSD) detector combined with in-situ tensile deformation of ε = 10%. Samples were first cold-rolled to 5% reduction and then deformed by uniaxial tensile along the transverse direction. Despite the use of a CMOS-based detector, analysis of deformation microstructure at such low plastic strains using EBSD is still challenging. Nevertheless in some grains details of the dominant deformation microstructure can be discerned. Slip line observations confirm that overall slip system activity is not influenced by the strain path change, but the EBSD observations show that in some cases dislocation boundary alignment is influenced by the presence of pre-existing boundaries, and in some grains the crystal rotations differ to those expected for tensile deformation of fully recrystallized grains of similar orientation.

In-situ formation of Al-alloyed surface layer on HH309 stainless steel by casting process

A new technique has been suggested to obtain an Al-alloyed surface layer on austenitic stainless steel by casting process. Before casting, the commercial pure aluminum foils with different thicknesses (50–300 μm) were adequately placed in the bottom of a copper mold, and then HH309 stainless steel melt was cast into this mold. The morphology, structure, composition and magnetic property of the superficial layer are characterized. The results showed that depending on the thickness of the initial foil, the thickness of the surface alloyed layer differ from about 10 to 80 μm, and its structure is mainly ferrite. The magnetic hysteresis loops indicated that γ→α transformation in the surface layer creates soft magnetic properties and further layer thickness causes more significant magnetization phenomenon. Also, microhardness measurements revealed a significant increase of hardness in the superficial layer due to the increase of Al content in this layer. The surface layer hardness was from 300 to 480 HV.

The role of the partial melting zone in the nugget growth process of unequal-thickness dissimilar aluminum alloy 2219/5A06 resistance spot welding

The effect of the partial melting zone on nugget growth in aluminum alloys’ resistance spot welding (RSW) process was investigated in this study by exerting same welding schedule on dissimilar 2219/5A06 aluminum alloys’ combination (of unequal-thickness) and commercial pure aluminum 1060 with the same gauge. A two-dimensional symmetrical finite model of unequal thickness RSW of which considering the coupling of the thermal, electrical and mechanical fields was exerted to reveal the dynamic nugget evolution under dissimilar 2219/5A06 aluminum alloys’ combination. Calculation of phase diagram (CALPHAD) technique was used to simulate the dynamic evolution of physical properties regarding the different phase portion at different local temperature. Between the solidus and the liquidus, both 2219 (548–645 °C) and 5A06 (449–626 °C) aluminum alloy exhibits a marked decrease in thermal and electrical conductivity. This leads to nugget shape evolution of dissimilar 2219/5A06 aluminum alloys’ combination (the peak diameter is not located at the workpiece/workpiece interface) differed from that of the commercial pure aluminum ones (the peak diameter is located at the workpiece/workpiece interface). Finally, by comparing the experimental and the calculated data, the model developed in this study provides a more reliable method to predict the size of the load-bearing plane when the effect of the partial melting zone is pronounced.

Direct Crystal Elastoviscoplasticity Model: An Application to the Study of Single Crystal Deformation

This paper models the uniaxial compression of a single crystal of commercial purity aluminum, and compares the modeling results with experimental data. The problem is solved using a first-type direct model based on the finite element method. The material behavior is described by a crystal elastoviscoplasticity model that explicitly accounts for shearing on crystallographic planes. The main feature of this study is a physically sound description of the geometric nonlinearity associated with crystal lattice rotation. The modeling results show that the original homogeneous single crystal is divided into volumes with different plastic shear rate intensity and lattice orientation, which is in satisfactory agreement with experimental data.

Effect of the Rate of Multiaxial Compression at Room Temperature on the Evolution of Microstructure of Commercial-Purity Aluminum

Commercial-purity aluminum of grade 1050 obtained by uniaxial or multiaxial compression at room temperature at deformation rates from 1.2 × 103 to 1.0 × 10 − 3 sec − 1 is studied. The true strain per one pass is kept constant while the total strain amounts to 1.6 in uniaxial deformation and to 3.0 in multiaxial one. The microstructure is determined using a transmission electron microscope. The high-rate deformation is shown to be the most effective for refining the structure due to elevation of the dislocation density and suppression of the dynamic recovery.

Microstructure and texture development in a polycrystal and different aluminium single crystals subjected to hydrostatic extrusion

A hydrostatic extrusion (HE) process was applied to commercial pure polycrystalline aluminium (99.9%) and two aluminium single crystals \(\langle {111}\rangle \) and \(\langle {110}\rangle \). On comparison, the results obtained from single crystals and polycrystalline aggregates are unique. Microstructure and crystallographic texture investigations were performed by transmission electron microscopy, electron backscatter diffraction and X-ray diffraction (XRD). Significant differences in grain refinement and texture formation were noticed depending on the starting orientation. The deformed single crystal with \(\langle {110}\rangle \) starting orientation features an average grain size value of 150% higher than the second investigated single crystal (\(0.5\ \upmu \hbox {m}\) for the \(\langle {111}\rangle \) single crystal and \(1.3\ \upmu \hbox {m}\) for the second crystal). In turn, the average grain size obtained for polycrystalline aluminium is \(0.9\ \upmu \hbox {m}\). The deformation process causes a difference in the grain sizes, while a fraction of the high angle grain boundaries have a comparable volume percentage in all the deformed microstructures—reached about 35%. The qualitative and quantitative XRD texture results proved that the HE process leads to the formation of a characteristic fibrous texture.

Study of structure of naturally aged aluminium after twist channel angular pressing

Twist channel angular pressing (TCAP), the severe plastic deformation (SPD) technology developed recently to increase the efficiency of the imposed strain and its homogeneity within a single pass, is an effective process combining channel bending and twist extrusion in a single die. The presented study analyses the phenomena of substructure development, precipitation, structural units' orientations, and the occurrence of residual stress, as well as electric resistivity and microhardness, in commercial purity aluminium naturally aged for two years at room temperature after processing via single pass TCAP. The results are compared with the findings for the TCAP sample right after processing; selected results are also compared with the results for the sample after TCAP and one year of natural ageing, and with a sample processed by conventional ECAP. The analyses showed the substructure to recover substantially, the grain size decreased to submicron size. The residual stress within the grains introduced by the energy accumulated via the severe imposed strain relaxed significantly by the structure restoration, as well as by intensive precipitation. The aged TCAP sample specific electric resistivity was comparable to the resistivity of the original commercially pure aluminium (2.652E-05 and 2.635E-05Ω·mm2·m−1, respectively), however, the microhardness mapping showed increased mechanical properties with homogeneous distribution.

Reply to comments on “Formation of twin boundaries in commercial purity aluminum with addition of Ti refiner”

Our original paper [1] reports some interesting results on the IQC-mediated nucleation mechanism for commercial purity aluminum with addition of 0.2 wt% Ti. However, the paper contains several imprecisions or inadequate statements suggested by the commenter [2]. This letter is to reply to the comments on reference [1] and to clarify several points, which do not seem to be fully explained in reference [1].

The effects of Ca addition on corrosion and discharge performance of commercial pure aluminum alloy 1070 as anode for Aluminum-air battery

The effects of Ca addition on corrosion and discharge performance of commercial pure aluminum alloy 1070 as anode for Aluminum-air battery

Characterization of AlN Inclusion Particles Formed in Commercial Purity Aluminum

The detailed characterization of nitride inclusion particles formed in the commercial purity Al melt has been carried out using advanced analytical electron microscopy assisted with pressure melt filtration and focused ion beam sample preparation techniques. It is found that the nitride inclusion particles have short rod-like morphology with an average length of 375 nm and an average width of 104 nm. Moreover, these nitride particles are identified to be hexagonal wurtzite AlN particles with the most close-packed plane, {0001}, as the exposed broad plane. Based on the crystallographic information, the potency of AlN as nucleation substrate for α-Al grain has been theoretically estimated from the lattice matching point of view. It is revealed that the interatomic spacing misfit along the close-packed directions on the close-packed planes between AlN and Al is 6.66 pct, indicating relatively strong potency of AlN as nucleation substrate for α-Al. However, it is suggested that AlN particles would rarely be involved in the nucleation and initiation of α-Al grains when competing with other oxide and boride inclusion particles normally present in the Al melt because AlN particles have larger misfit with Al, comparable or even smaller size, and lower number density than oxides and borides.

Synthesis of nanoscale spherical TiB2 particles in Al matrix by regulating Sc contents

Abstract

Robust and superhydrophobic coating highly resistant to wear and efficient in water/oil separation

Here, we report a straightforward and rapid process using fatty acids to produce a stable superhydrophobic hybrid composite coating on aluminium substrate which is highly resistant to wear under environmental conditions. Furthermore, this novel superhydrophobic metal surface is highly efficient at separating of water/oil systems. The single-step process we adopt involves electrochemical deposition of ZnCl2, α-Al2O3 and lauric acid (C11H23COOH) onto commercial pure aluminium substrate. The resultant static contact angle (170°) and sliding angle (1°) are those of a superhydrophobic coating with self-cleaning properties; while chemical analysis shows that this is the result of generation of zinc laurate (Zn(C11H20COO)2) as a major compound that increases the superhydrophobic character of the coating, generating a flower-like structure 70 nm thick. Different wear tests show the coating is resistant to severe conditions, confirming its real potential against weathering, including sand and water erosion. Finally, a water/oil separation test determined 99% separation efficiency in hexane and ether petroleum systems, in a laboratory-made storage tank.

Fabrication and characterization of nanoporous anodic alumina membrane using commercial pure aluminium to remove coliform bacteria from wastewater

Nanoporous anodic alumina (NAA) membranes were produced by anodizing process using commercially pure aluminium (1050 alloy). The optimization of processing parameters, such as applied potential, temperature and time in two different electrolyte solutions, has been performed to produce the ordered alumina nano-membrane. Nanoporous anodic alumina membrane (NAAM) was obtained by removing the aluminium substrate and opening the bottom of the pores. The microstructure of samples was studied and analysed by field emission scanning electron microscopy (FESEM). Image processing of FESEM pictures was performed with MATLAB. The results showed that at the optimum conditions of anodizing, the percentage of porosity and ordering of pores in the samples were similar to the productions of the high purity aluminium base. NAA layers that formed in sulphuric acid solution in comparison with oxalic acid had lower pore diameter (20 nm), lower inter-pore distance (45-50 nm) and higher hardness (325HV). The optimized membranes which have been produced with the same thickness were used for separation of Coliform bacteria from the secondary clarified wastewater. The results showed that these membranes can be used as selective filters because of their desirable physical properties.

Superhydrophobic Coating Bioinspired on Rice Leaf: A First Attempt to Enhance Erosion Resistance Properties at Environmental Conditions with Ceramic Particles

This study develops a new, facile and rapid process bioinspired on rice leaf with the aim of producing a hybrid composite coating in a first attempt to obtain a superhydrophobic coating with enhanced erosion resistance properties. Rice leaves (Oryza sativa L.) are made of hierarchical structures consisting of micropapillae and waxy nanobumps which confer to the surface a contact angle of 164° as Lotus leaf does. In particular, rice leaves accumulate amorphous silica inside and on the surface with various morphologies. This kind of silica is produced by absorbing silicates from the soil under specific conditions of temperature and pressure. The presence of biosilica in rice leaves is useful for preventing diseases or improves mechanical properties of the leaves. Single-step and two-step processes are the two strategies applied for generating a superhydrophobic coating by electrochemical deposition of ZnCl2, α-Al2O3 and lauric acid (C11H23COOH) onto commercial pure aluminum substrate. The static contact angle measured on the coating gives values of 170° and 1° for the sliding angle conducing to a coating with superhydrophobic and self-cleaning properties. Various characterization techniques are used to determine chemical and morphological structure such as FESEM, XPS or FTIR. On one hand, in morphological analysis, flower-like structure is obtained with petals thickness of 70nm corresponding to the nanostructured contribution to the system. On the other hand, chemical analysis concludes the generation of zinc laurate (Zn (C11H23COO)2) as a major compound contributing to the reduction of surface tension and increasing the superhydrophobic character of the coating as well.

EXPERIMENTAL INVESTIGATION OF P/M PARTS MANUFACTURING CONDITIONS USING AA2014 AND ELEMENTAL AL AND CU POWDERS

Bu çalışmanın amacı, iki farklı AA2014 toz grubundan (önalaşımlı, elementel formda) elde edilen numunelerin mekanik test sonuçları, kırık yüzey analizi ve metalografik çalışmalarını karşılaştırarak, elementel tozun kullanımıyla elde edilen değerlerin tasarım malzemesi olarak yeterli mekanik özelliklere sahip olup olmadığını belirlemeye çalışmaktır. Ön alaşımlı (AA2014), elemental alüminyum ve bakır tozları kullanılarak klasik toz metalurjisi (TM) yöntemiyle numuneler üretilmiştir. AA2014 alaşımının içerdiği oran kadar, ticari saf Alüminyum tozuna bakır eklenmiş ve dökümde soğuk presleme yapılmıştır. Benzer koşullarda, ön alaşımlanmış (AA2014) tozlar ve element tozlarından benzer bir bileşim elde etmek için harmanlama ve karıştırma işlemleri gerçekleştirilmiştir. Sinterleme koşulları olarak, üç farklı sıcaklık (600°C, 610°C, 620°C) kullanılmış ve sinterleme süresi sabit tutulmuştur (30 dakika). Bu aşamada, alüminyum matriksinin katı çözeltiler oluşturmak için Bakır atomlarını çözmesi beklenir. Bu durumun gerçekleşmesini incelemek için metalografik çalışmalar yapılmıştır. Sonuç olarak, alüminyum ve bakır tozu, uzun bir kalıp ömrü için alaşımlı AA2014 yerine elemental olarak kullanılabilir.

Grain Refinement of Al-5Ti-0.62C-0.2Nd Grain Refiner for Commercial Pure Aluminum and Its Effect on Mechanical Properties

It is well known that the mechanical properties of commercial pure Al are influenced by size of α-Al dendrites. In the present work, Al-5Ti-0.62C-0.2Nd grain refiner was prepared by a pure molten aluminum thermal explosion reaction, and its effect on grain refinement and mechanical properties of commercial pure Al was investigated. Microstructure and phase composition show that Al-5Ti-0.62C-0.2Nd grain refiner consists of α-Al, granular TiC, lump-like TiAl3, and block-like Ti2Al20Nd. Grain-refining tests on commercial pure Al show that an Al-5Ti-0.62C-0.2Nd grain refiner has better refining performance compared with Al-5Ti-0.62C grain refiner. With addition of 0.2-wt.%-Al-5Ti-0.62C-0.2Nd grain refiner, the average grain size of commercial pure Al can be refined from roughly 2800 to 155±5 µm effectively, and it has higher resistance to grain-refinement fading. On account of the grain refinement, the tensile strength and elongation are increased by approximately 18.3% and 83.5%, respectively.

Feedstocks of Aluminum and 316L Stainless Steel Powders for Micro Hot Embossing

In metal powder, shaping the preparation and characterization of the feedstock is an aspect commonly recognized as fundamental. An optimized composition is required to ensure the successful shaping of the feedstock. In this study, a commercial binder system, pure aluminum and 316L austenitic stainless-steel powders were used for micro hot embossing. The optimization process revealed that powder characteristics such as shape and the stability of the torque mixing, were important parameters. Manipulating the feedstock composition by adding multi-walled carbon nanotubes or stearic acid or using a higher powder concentration considerably influenced the torque mixing values. The steady state of torque mixing was achieved for all feedstocks. This torque behavior indicates a homogeneous feedstock, which was also confirmed by microscopic observations. Nevertheless, an extruding process was required for greater homogeneity of the aluminum feedstocks. The presence of the carbon nanotubes increased the homogeneity of green parts and reduced microcrack formation. The roughness was essentially dependent on the feedstock composition and on the plastic deformation of the elastomer die. Shaping the prepared feedstocks (with or without carbon nanotube) was achieved by the optimized powder concentrations and it did not increase by the stearic acid addition.

NALYSIS OF CLOSED DIE COLD FORGING FOR SPUR GEAR USING THREE DIMENSIONAL SLAB TECHNIQUE

The present study is concerned with upset forging of arbitrarily-shaped prismatic blocks which is characterized by three-dimensional deformation. From the proposed velocity field, the upper-bound load and deformed configuration are determined by minimizing the total power consumption with respect to some chosen parameters; such as the proposed method of analysis in this work can be used for prediction of forging load and deformation in upset forging of arbitrarily-shaped prismatic blocks. Closed-die forging of toothed disk is investigated using the slab method technique The tooth regions are approximated by prismatic rectangular sections. The velocity field comprising three-unit deformation regions is used. A constant frictional stress between work-piece and forging die is assumed. The average punch pressure normalized by the flow stress of the billet material is determined theoretically and compared with the present experimental results The experimental work is carried out on a commercial pure Aluminum (Al 1100) at room temperature The forging process is carried out using one die geometry without using any additional blocker dies. The theoretical predictions of forging pressures and deformation configurations are in good agreement with the experimental results. The experimental work proves that the analysis is good within approximately 36% of error according to many parameters.

Preparation and synthesis thermokinetics of novel Al-Ti-C-La composite master alloys

The new type of Al-Ti-C-La master alloy was prepared by commercial pure Al, Ti powder, graphite powder, Al powder and La2O3 powder by aluminum melt in-situ reaction method. The microstructure and the effect on commercial pure aluminum of Al-Ti-C-La master alloy have been studied by means of X-ray diffraction (XDR), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry (EDS). The synthesis thermodynamics and kinetics of Al-Ti-C-La master alloy were analyzed. The experiment shows that Al-Ti-C-La master alloy is composed of Al, Al3Ti, TiC and Ti2Al20La. The refining performance of the prepared Al-Ti-C-La master alloy is obviously better than that of Al-Ti-C master alloy when the addition of rare earth oxide La2O3 is 10 wt% and the preparation temperature is 930 °C. The analysis of thermodynamic calculation and the process of kinetics demonstrate that, in the preparation process of Al-Ti-C-La master alloy, firstly, Al reacts with Ti to produce Al3Ti, C reacts with Ti and Al3Ti to form TiC based on the aluminothermy reaction. Rare earth oxide La2O3 and C powder react with Ti powder and O2 in the air occur to generate CO, TiC, [La] atoms and LaC2. [La] atoms adsorb on the surface of Al3Ti to form the new rare earth compounds Ti2Al20La.

Comment on “Formation of twin boundaries in commercial purity aluminum with addition of Ti refiner” by Zhongwei Chen, Jianping Gao, Kang Yan

Abstract This paper reports the iQC-mediated nucleation mechanism for another aluminum alloy, which we have identified first in Al-Zn:Cr [1] and then in Au-Ag-Cu:Ir [2] . As such, this is an interesting result but there are unfortunately two problems: The paper contains several errors or imprecisions on one hand, and the text is written with a lack of proper references and inadequate statements.