Microanalysis Studies Research Articles

Sedimentological perspectives on climatic, atmospheric and environmental change in the Neoproterozoic Era

AbstractSedimentological insights underpin many of the important recent advances in understanding of Earth system behaviour in the Neoproterozoic Era. This article reviews three main areas: (i) chemical proxies and their preservation, with emphasis on carbonate facies; (ii) glacial and post‐glacial facies, including their age constraints; (iii) sedimentary evidence for biotic innovations and responses. Chemostratigraphy plays an important role in ordering Neoproterozoic events and defining disturbances to the carbon cycle. There is increasing attention being paid to assessing the role of diagenetic origination or modification of chemostratigraphic signals. Alongside this, new criteria for identifying primary dolomite and precursor metastable phases such as ikaite have been developed. In respect of oxygenation, geochemical proxies substantiate the concept of a Neoproterozoic Oxygenation Event as a very gradual transition, the ocean being at any one time a heterogeneous assemblage of ferruginous, sulphidic and oxic conditions, with some evidence of increasing deep‐sea oxidation through the Ediacaran Period. Techniques such as Fe‐speciation need to be supplemented with proxies sensitive to suboxic conditions. More generally, it is predicted that petrographically constrained microanalytical studies will also become more important in reconstructing palaeoenvironmental conditions. The global distribution of Neoproterozoic glacial deposits combined with palaeomagnetic evidence supports the concept of panglaciations in which ice sheets reached sea‐level in the tropics. Advances in radiometric dating have demonstrated the synchronous onset of global (Sturtian) glaciation at 717 Ma and the demise of a second (Marinoan) glaciation at 635 Ma, and plausibly indicate long durations for each (55 Myr for Sturtian and 5 to 15 Myr for Marinoan). However, a compilation of radiometric dates indicates ambiguities indicating the need for further improvements to the radiometric and Sr‐isotope database to understand events within the Sturtian time frame, the timing of onset of Marinoan glaciations, and the age and synchroneity of individual negative δ13C anomalies. Sturtian deposits are typically thick, rift‐related successions containing a range of environments influenced or dominated by dynamic glaciers, as well as ice‐free marine intervals. Marinoan glacial deposits, by contrast, tend to be thin and continental. During the latter interval, oxygen isotope systematics of sulphate demonstrate that atmospheric CO2was high, as predicted by Snowball Earth theory, and that sedimentation was influenced by orbital forcing. The Sturtian record, by comparison, needs to be searched for evidence of cold‐climate hiatuses on the one hand and orbital forcing on the other. Cap carbonate formation appears to have coincided with rising sea‐levels following panglaciations. Snowball theory considers that they formed rapidly in the postglacial greenhouse, but an alternative model of slower formation with clastic sediment starvation during transgression may prove to be consistent with new data and models showing extensive glacier terminations on land. For all facies, but especially caps, the use of microanalytical techniques and holistic studies of petrogenesis are future priorities. There are important discrepancies between molecular clock predictions of early metazoan origination and the hard evidence from sedi‐mentary records which largely depend on local exceptional preservation by early diagenesis. A variety of life survived panglaciation, and there is little evidence that glaciations directly caused oxygenation or stimulated evolution.

Editorial

Traditionally microscopy has been separated into materials and biological applications, but these divisions break down in fields such as nanotechnology and tissue engineering where there is a need to understand actions of materials components at the cellular and intracellular level. Microanalytical techniques with their ability to identify elemental content at the nm scale offer considerable promise in these areas of research, but their application is not always straightforward. Routine procedures developed for specific applications in one field are not always appropriate when applied in another, and may cause misleading results. This issue of J Microsc. brings together a number of papers dealing with the application of microanalysis at the interface between materials science and biology. The subjects dealt with include the effects of standard fixation and embedding procedures on nanoparticle composition, (Cross et al.), the inadvisability of using standardless quantitation routines with biological specimens (Warley), problems encountered in SEM analysis of cells cultured on biocompatible substrates (Tylko) and correlation of results produced from FIB SEM with those from TEM to overcome sampling problems that occur in thin section TEM studies (Hondow et al.). Lawrence et al. present their results achieved using soft X-rays as the source of X-ray excitation, the advantage of this technique being that minimal specimen preparation is required. Whilst Zeitvogel et al. present a plug in for Image J to tackle the problem of extracting information from the large data sets that can be produced from microanalytical studies. Together these papers tackle different aspects of problems that may be encountered when undertaking analysis at the materials biology interface and should provide a very useful reference point for workers in the field.

Volume change behavior of lime treated gypseous soil — influence of mineralogy and microstructure

Series of oedometer tests and micro-analytical studies (XRD, SEM and EDAX) have been carried out to investigate the influence of varying gypsum content on swell, compressibility and permeability of lime treated montmorillonitic soil after curing for different period. Immediate swell is observed on inundation of compacted samples with water and continuously increased with gypsum content. However, changes in swell are found to be marginal with curing. This is attributed to the formation and growth of ettringite crystals by ionic reactions of aluminum–calcium–sulfate in the presence of water which is confirmed through detailed micro-analysis. The higher swell in uncured specimens and gradual reduction in swell with increase in curing periods are due to relative dominance of formation and growth of ettringite and cementitious compounds, respectively. Also, the ionic reaction products are found to bear a significant influence on the compressibility and permeability behavior.

Mineralogical and isotopic studies of base metal sulfides from the Jiawula Ag–Pb–Zn deposit, Inner Mongolia, NE China

The Jiawula Ag–Pb–Zn deposit is located in the northern part of the Da Hinggan Mountains metallogenic belt in the eastern section of the Central Asian Orogenic Belt. Sphalerite, galena, pyrite, chalcopyrite, and arsenopyrite are the major sulfide minerals occurring in this deposit. Here we report results from electron probe micro-analysis (EPMA), thermoelectricity, and sulfur isotope studies of the constituent silver minerals and sulfide phases of the Jiawula deposit. Petrographic observations and EPMA study reveal abundant silver mineralization in the ore, especially within sphalerite and galena. Discrete grains of silver minerals (including argentite, pyrargyrite, and canfieldite) and isomorphism in silver-bearing sulfides are identified. Silver and tellurium contents in galena are relatively high and show interrelationship. Significant substitution of S by Te in the galena lattice facilitates silver entering the galena structure, which might have been promoted by relatively low lgfS2. The thermoelectric coefficient of pyrite shows a marked gradient from N-type to P-type from pre- to post-metallogenic stages. Pyrites in Jiawula are enriched in Co and As and in the absence of Ni, displaying features typical of epithermal deposits. The isotopic data present a close relationship between the sulfur source and magmatism.

Micro-analytical studies on sugar cane bagasse ash

The worldwide production of sugar generates large volumes of bagasse wastes, which are burnt in uncontrolled manner for heating boiler, which are deposited in landfills, which create negative effects in the environment. The ash obtained by burning bagasse is generally used as Supplementary Cementing Material (SCM) in concrete production without proper knowledge of pozzolanic material characterization. This paper summarizes the results obtained from the various techniques to determine pozzolanic mineral profiles in sugarcane bagasse ash (SCBA). Techniques employed in the present study include X-Ray Diffraction (XRD), Energy-Dispersive X-ray Analysis (EDAX) spectrometer, Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermal Analysis [Thermo-Gravimetric Analysis (TGA) and Derivative Thermo-Gravimetric (DTG)] in order to understand the type, form, nature, morphology, concentration, etc. of pozzolanic minerals.

White spots on Smoke Rings by Bruce Nauman: Microanalytical study of a contemporary artwork

White spots on Smoke Rings by Bruce Nauman: Microanalytical study of a contemporary artwork

Combined X‐ray microanalytical study of the Nd uptake capability of argillaceous rocks

Argillaceous rocks are considered as suitable host rock formation to isolate the high‐level radioactive waste from the biosphere for thousands of years. Boda Claystone Formation, the possible host rock formation for the Hungarian high‐level radioactive waste repository, has geologically and mineralogically been studied in detail, but its physico‐chemical parameters describing the retention capability of the rock needed further examinations. Studies were performed on thin sections subjected to 72 h sorption experiments using inactive Nd(III). Nd(III) has been used as a chemical analogue for transuranium elements of the radioactive waste to examine the ion uptake capability of the micrometre size mineral phases occurring in the rock. The elemental mapping of synchrotron radiation‐based microscopic X‐ray fluorescence (micro‐XRF) combined with scanning electron microscopy energy dispersive X‐ray analysis (SEM/EDX) has sufficient sensitivity to study the uptake capability of the different mineral phases on the microscale without the necessity of applying radioactive substances. Elemental maps were recorded on several thousand pixels using micrometre magnitude spatial resolution. By interleaving micro‐XRF and SEM/EDX data sets from the same sample area and applying multivariate methods, calcite and clay minerals could be identified as the main mineral phases responsible for Nd(III) uptake without using additional microscopic X‐ray diffraction mapping. It should be highlighted that the ion uptake capability of dolomite containing calcium and magnesium could be distinguished from the characteristics of calcite only by the interleaving of micro‐XRF and SEM/EDX data sets. The presence of minerals was verified by applying microscopic X‐ray diffraction point measurements. Copyright © 2015 John Wiley & Sons, Ltd.

Microanalysis and preliminary pharmacokinetic studies of a sulfated polysaccharide from Laminaria japonica

A rapid, sensitive and reproducible high performance liquid chromatography (HPLC) method with post-column fluorescence derivatization has been developed to determine the amount of low-molecular-weight sulfated polysaccharide (GFS) in vivo. The metabolism of GFS has been shown to fit a two component model following its administration by intravenous injection, and its pharmacokinetic parameters were determined to be as follows: half-time of distribution phase (t 1/2α)=11.24±2.93 min, half-time of elimination phase (t 1/2β)=98.20±25.78 min, maximum concentration (C max)=110.53 μg/mL and peak time (T max)=5 min. The pharmacokinetic behavior of GFS was also investigated following intragastric administration. However, the concentration of GFS found in serum was too low for detection, and GFS could only be detected for up to 2 h after intragastric administration (200 mg/kg body weight). Thus, the bioavailability of GFS was low following intragastric administration because of the metabolism of GFS. In conclusion, HPLC with postcolumn derivatization could be used for quantitative microanalysis and pharmacokinetic studies to determine the presence of polysaccharides in the serum following intravenous injection.

Electron probe X-ray microanalysis studies on the distribution change of intra- and extracellular calcium in the elongation zone of horizontally reoriented soybean roots.

To clarify the contribution of Ca to the gravitropic response, quantitative X-ray microanalyses were performed on cryosections of roots of soybean seedlings reoriented horizontally from their original vertical orientation. After reorientation, the roots bent gradually toward the ground at the elongation zone. The concentrations of Ca in the cell walls, cytoplasmic matrices and central vacuoles of cortical cells were measured in the upper and lower halves of the elongation zone at 0, 30, 60 and 120 min after reorientation. The Ca concentration did not significantly change in the cytoplasmic matrices or vacuoles. Additionally, the Ca concentration did not change significantly in cell walls at 30 min after reorientation; however, beyond 30 min, this concentration significantly increased gradually in the lower half of the elongation zone and decreased in the upper half of the elongation zone, indicating a typical asymmetrical distribution of Ca. These results suggest that Ca moves apoplastically in soybean roots to produce an asymmetrical Ca distribution in the elongation zone, which contributes to root curvature. The possible role of Ca in accelerating or repressing the effect of auxin is also discussed in this study.

Spoilage of oat bran by sporogenic microorganisms revived from soil buried 4000 years ago in Iranian archaeological site

The Bronze Age archaeological site of Shahr-i Sokhta (30° 39′ N; 61° 24’ E), located today in southeastern Iran, Sistan region, is a special archaeological deposit in which the exceptional preservation of human, plant and animal remains, due to the dry climate of the region, can provide detailed information on one of the first complex proto-urban societies. In recent years, there has been growing interest in changes in local climate and environment as major reasons why the settlement was abandoned about 4000 years ago. Food shortage has been regarded as a direct effect of these changes. No attention has been paid to the potential health hazards associated with ancient urban/domestic pollution, although large garbage deposits have been found in several parts of the site.During excavations in 2007, four soil samples were taken under aseptic conditions at a depth of 1.5–2 m in a stratified deposit sealed by the floor of a small house, dated to the second half of the third millennium BC. Microbiological, palynological, carpological and microanalytical studies were performed on the four soil samples. Site C was identified as the most affected by human activity. Failure of conventional methods of detecting culturable and unculturable microbes in site C indicated the need for specific culture conditions suggested by palynological observations. Since oat seed residues were identified among the archaeobotanical material, oat bran was used as carbon and energy source to make a new medium to revive microbes. Coarsely ground oat bran was sterilized twice and soaked with minimal medium as sole carbon source. About 50 mg of buried soil from site C was added to the medium in cell culture flasks with aerobic and anaerobic stoppers and incubated at 28–30 °C and at 4 °C.After incubation under aerobic and anaerobic conditions, five sporogenic microbes were identified by sequencing 16S rDNA and ITS rRNA regions: a sporogenic strain IRC3 identified as Bacillus sp. was the only isolate under anaerobic conditions, whereas under aerobic conditions four moulds were isolated: Aspergillus flavus IRC1, Penicillium crysogenum IRC2, Cladosporium sp. IRC4, and the psychrotroph Aspergillus restrictus IRC5. Bacillus sp., with 99.7% similarity to Bacillus subtilis, broke down oat bran, producing a gel, while Cladosporium sp., with 99.8% similarity to Cladosporium sphaerospermium, grew on oat bran by synthesizing intracellular lipids. All these microbes are known to spoil food and they are common where there is intense human activity.

Micro-analytical study of two 17th century gilded miniature portraits on copper

Two gilded miniature portraits on copper support from the Evora Museum collection (Portugal) were examined and analysed by stereomicroscopy, μ-Raman spectroscopy, SEM–EDS, portable-XRF (pXRF), μ-FTIR spectroscopy and liquid chromatography coupled to diode array and mass spectrometry detection (LC-DAD-MS). Both portraits, one of a gentleman and the other of a lady, are notable paintings of comparable richness, which present several areas painted or covered with gold (namely, gold dust to compose and highlight different ornaments and gold leaf to cover the back of one of the portraits). The gold dust, the gold leaf and the materials used in the gilding technique were investigated non-invasively and non-destructively using stereomicroscopy, SEM–EDS, pXRF and μ-FTIR. The other materials of the paintings, like the inorganic pigments and extenders, were successfully identified by μ-Raman spectroscopy, while the organic red pigment cochineal lake was positively identified by LC-DAD-MS. Overall, the materials identified in these 17th century paintings are broadly consistent with those mentioned in the painting treatises of that time, or with those reported in a very limited number of material studies focused on artworks of the same kind and period.

Quantitative Energy-Dispersive X-Ray Microanalysis of Chlorine in Cement Paste

AbstractEnergy dispersive X-ray spectroscopy (EDS) is a microanalysis technique for material characterization that can provide accurate quantification of elemental composition while maintaining high spatial resolution. EDS microanalysis studies on cementitious materials can face several challenges essentially due to the complex chemical and mineralogical characteristics of cement hydration products. Furthermore, EDS microanalysis is widely carried out in “standardless analysis” mode, which relies on the internal standards of the microanalysis software. This can lead to highly erroneous analysis results because standardless analysis typically normalizes total to 100% without taking chemically bound water into account. In the case of quantifying chlorine content of a cement paste, such normalization is unacceptable because it can lead to overestimation. For accurate determination of elemental concentrations, X-ray spectra collected from minerals or glasses with known chemical compositions are necessary as r...

High concentration of phosphorus is a distinctive feature of myelin. An X-ray elemental microanalysis study using freeze-fracture scanning electron microscopy of rat sciatic nerve.

We have used rat sciatic nerves submitted to freezing and freeze-fracture to determine the elemental composition of small domains of the peripheral nerve studied at high resolution by scanning electron microscopy. We found that myelin of Schwann cells is unique in its high content in phosphorus (P) that was more than 10 times higher than P measured in any other cells. This high concentration in P makes myelin chemistry suitable of monitoring at the subcellular level using the herein described methodology.

Microanalytical study of varves in the recent sediments of Lake Bele

The inner structure of varves in the recent sediments of Lake Bele, Khakassia, is studied via X-ray fluorescence microanalysis at the Siberian and Shanghai Centers of Synchrotron Radiation. Similar experimental conditions apply in both cases: excitation energy, 20–22 keV; size of exciting radiation spot, 80–100 μm; scanning step, 100 μm. The dates determined for marking layers coincide. The experimental results shed new light on the geochemistry of sedimentation processes and help estimate the current sedimentation rate.

Estudio exploratorio de la interacción colaborativa infantil en la realización de dibujos libres

Objective. This paper presents an exploratory and micro-analytical study of peer collaboration among children in a free drawing task. The characteristics of this process were also analyzed according to age group and socioeconomic context. Method. Cross-sectional research in which 82 children were grouped into 41 dyads. They were 4-, 8- and 12-years-old, belonging to advantaged and disadvantaged socioeconomic contexts. Each dyad performed a collaborative free drawing task. The main instrument was observation. The interaction was analyzed from two approaches: social modality of execution, and specific verbalization. Each approach was coded by a different system of categories. The data was processed by factorial and cluster analysis. Results. Data showed three global interactive modalities: dissociative (mainly associated with 4-years-old dyads), mixed (collaborative-asymmetrical) and cooperative (the last two mainly associated with 8- and 12-yearsold dyads). Also detected were specific associations between mixed modality – disadvantaged context and cooperative modality – advantaged contexts. Conclusion. The study offers new evidence on two main issues in recent studies on peer collaboration: a) the focus on the micro-analysis of interaction; b) the growing interest on more open-ended tasks compared to traditionally addressed tasks (problem solving and tasks in science or mathematics). Also, the current paper allows analyzing action and language jointly in collaborative interaction, considering that they were studied separately in most of investigations.

Synthesis, antimicrobial and antitubercular activities of some novel pyrazoline derivatives

In the present study, two new series of pyrazolines (3a–h &4a–h) were synthesized starting from p-acetamidophenol (paracetamol) and evaluated for their antibacterial, antifungal and antitubercular activities. Chalcones (2a–h) prepared by condensing 3-acetyl-4-hydroxyphenyl acetamide (1) with different aromatic aldehydes were reacted with phenyl hydrazine and isonicotinic acid hydrazide to obtain phenyl-pyrazolines (3a–h) and isoniazid-pyrazolines (4a–h), respectively. The structures of the synthesized compounds were confirmed by spectral and microanalysis studies. Newly prepared pyrazoline compounds exhibited significant antibacterial activity against the organisms Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa when compared with the standard antibiotic Ciprofloxacin. Compound 4g showed potent antibacterial activity against P. aeruginosa and S. aureus (MIC-3.12μg/mL), however, against E. coli compound 3d, 4c, 4d, 4f &4g were found to have an MIC of 6.25μg/mL. Antifungal activity of compound 4d against Candida albicans and Aspergillus niger (MIC-3.12μg/mL) was found to be better than the standard drug Ketoconazole. The results of antitubercular activity of the synthesized compounds against Mycobacterium tuberculosis H37Rv by the agar microdilution method are quite promising. The antitubercular activity of compounds 4c, 4d &4g (MIC-3.12μg/mL) was found to be superior than that of the reference drug Streptomycin which showed MIC equal to 6.25μg/mL. It was observed that pyrazolines with chloro, nitro or methoxy substituent showed better activity. Also, the pyrazolines derived from isoniazid (4a–h) were found to be better in their antibacterial, antifungal and antitubercular action than those derived from phenyl-hydrazine (3a–h).

Exploring the influence of crystal environment on the geometry of bis(pyridine-2,6-dicarboxylato) chromium (III) anionic complexes containing various cationic moieties: Synthesis, structures and Hirshfeld surface analysis

Two chromium (III) complexes with pyridine-2,6-dicarboxylate ligand have been synthesized with various cations yielding new compounds: (2a4mpy)2[Cr(pydc)2]2·9H2O (I) and (bphda)[Cr(pydc)2]2·DMF·4H2O (II) where pydc=pyridine-2,6-dicarbocylate anion, 2a4mpy=2-amino-4-methylpyrimidinium cation and bphda=1,1′-bisphenyl-4,4′-diaminium cation. These compounds have been characterized by IR spectroscopy, CHN microanalysis and X-ray structural studies along with a detailed analysis of Hirshfeld surface and 2D fingerprint plot as an assisting tool for decoding of the intermolecular interactions. In both complex fragments, Cr(III) atoms are surrounded by four oxygen atoms and two nitrogen atoms from two pydc ligands, forming a distorted octahedral environment. Crystal packing in both compounds is mostly governed by strong OH⋯O and NH⋯O classical hydrogen bond interactions and assisted by the interactions involving π-electrons, namely π⋯π off-face stacking, carbonyl⋯π or lone pair⋯π. All these interactions lead to rather complex three-dimensional structures. In this regard, the fingerprint plots enabled to explore the role of intermolecular interactions types on the distorted geometry of titled complexes and analogous structures retrieved from Cambridge Structural Database (CSD).

Microanalytical study of sub-nanoliter samples by capillary electrophoresis – mass spectrometry with 100 % injection efficiency

A method is presented for conducting fast capillary electrophoresis (CE) with ultrasmall sample volumes (<10 nL) and subsequent determination of target analytes by time-of-flight mass spectrometry (TOF-MS). Furthermore, an approach towards preconcentration by solvent evaporation of samples as small as 500 nL is shown. Ultrasmall samples of biologically important cyclic nucleotides (cyclic guanosine monophosphate, cyclic adenosine monophosphate, cyclic cytidine monophosphate) served as model compounds. Sample volumes as small as 500 pL were used to perform sample uptake and CE injections by capillary batch injection (CBI). This resulted in detection limits between 2 and 5 fmol. The fast rate of sample evaporation prevents the operation of nano-/subnano-liter samples under room temperature conditions. A CBI-CE-TOF-MS setup incorporating a Peltier element and a thermostat was used for the handling of very small samples. In combination with tapered fused silica injection capillaries and the high-precision guiding system of the CBI setup, nearly 100 % efficient injections of ultrasmall samples into funnelled separation capillaries could be managed. The overall system allowed for high-throughput CE separations from densely arranged sample droplets or vials with RSD of peak heights ranging from 6 to 8 % (n = 5). CE-TOF-MS separations of mixtures of cyclic nucleotides were carried out in capillaries as short as 20 cm (25 μm ID) in less than 55 s with high separation efficiency. We report details of the setup and optimizations with respect to etching of capillaries (tapering and funnelling), sample uptake and injection as well as separation of the model compounds. Moreover, the capabilities of the experimental setup for preconcentration of target analytes by solvent evaporation are described. Preconcentration factors of up to 100 could be achieved. This approach was successfully used for the determination of the cyclic nucleotide cGMP in (spiked) human urine samples.

Dielectric properties of high-permittivity A2/3CuTa4O12 ceramics

Purpose – This paper aims to present the comparative study on the composition, microstructure and dielectric behavior of a group of new nonferroelectric high-permittivity A2/3CuTa4O12 (A = Y, Nd, Sm, Gd, Dy or Bi) ceramics. Design/methodology/approach – The materials under investigation were synthesized by solid-state reaction method and sintered at 1,120-1,230°C. Dielectric properties were investigated in the temperature range from −55 to 740°C at frequencies 10 Hz to 2 MHz. Microstructure, elemental composition and phase composition of the ceramics were examined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) methods. DC conductivity was studied in the temperature range 20-740°C. Findings – XRD analysis revealed peaks corresponding to Cu2Ta4O12 along with small amounts of secondary phases based on tantalum oxides. Impedance spectroscopic data and the results of SEM and EDS studies imply the spontaneous formation of internal barrier layer capacitors in the investigated materials. Two steps can be distinguished in the dielectric permittivity versus frequency plots. The low-frequency step of 1,000-100,000 is assigned to grain boundary barrier layer effect, while the high-frequency one of 34-46 is related to intrinsic properties of grains. Originality/value – Search for new high-permittivity capacitor materials is important for the progress in miniaturization and integration scale of electronic passive components. The paper reports on processing, microstructure, microanalysis studies and dielectric properties of a group of novel nonferroelectric materials with the perovskite structure of CaCu3Ti4O12 and the general formula A2/3CuTa4O12, being spontaneously formed internal barrier layer capacitors.

Fabrication of Micro-sized Al/Cu Clad by Repeated Hydrostatic Extrusion and Its Mechanical Properties

Al/Cu clads were fabricated by hydrostatic extrusion at 523 K, and their microstructure and mechanical properties were evaluated. The cell size of the Al/Cu clads decreases from 12 mm to 600 µm after three passes of extrusion. Intermetallic compounds (IMCs) appeared at the interface of Al/Cu clad during annealing at 683 K, and their sizes increased as a function of the annealing process. X-ray microanalysis and scanning electron microscope studies showed that the intermetallic species were CuAl2, CuAl, and Cu3Al2, and the thickness of the IMC layers increased at different rates depending on the annealing time. The formation and growth of IMCs resulted in an increase of yield strength and a decrease in elongation of the clads under tensile testing.