Aluminum Surface Research Articles

IDP-Net: Industrial defect perception network based on cross-layer semantic information guidance and context concentration enhancement

Applications in Engineering: In industry, surface defect detection is crucial for improving product quality. However, there are many challenges in industrial inspection scenarios, such as interference from background noise, complex small-target problems, significant variations in target objects, and the problem of finding a balance between inspection speed and accuracy. To address the above problems, this paper proposes an industrial defect-aware network based on cross-layer semantic information guidance and contextual attention enhancement (IDP-Net). Specifically, IDP-Net has four different new features. The contribution of artificial intelligence: Firstly, to solve the industrial surface context and defect similarity problem, this paper proposes a Lightweight Local Global Feature Extraction Network (LLG-Net), unlike other methods, the effective combination of self-attention blocks and convolution blocks ensures gradual integration of global and local features across multiple layers, to improve the detection ability of targets with significant changes in scale, this paper designs a Multiscale Perceptual Feature Aggregation Network (MPA-Net), adequately fuses the shallow fine-grained information and the deep semantic information. Then, to enhance the connection between multi-scale semantic information, an adaptive cross-layer feature fusion module (ACFF) is proposed, which is novel in integrating the characteristics of multiple adjacent levels to help the model better capture the different scale characterisation of the target. Finally, a Region Attention Module (RAM) is proposed and introduced in the detector to enhance the attention to the critical regions around the target object. In particular, this paper proposes a new localisation loss function (MEIoU) that enhances the network’s attention to objects at different scales. The experimental results show that 94.3%, 98.7% and 99.5% of mAP@.5 are obtained on steel, PCB and aluminium surface defect datasets, respectively, and 50 FPS is achieved, which is better than the current mainstream detectors and meets the demand of practical industrial production.

Kinetic Study of the Aluminum–water Reaction Using NaOH/NaAlO2 Catalyst for Hydrogen Production from Aluminum Cans Waste

The presence of oxide layers covering the surface of aluminum is known to impede the hydrogen production reaction. These oxide layers can be broken by adding catalysts and increasing the aluminum-water reaction temperature. Common catalysts used are alkaline catalysts that are capable of achieving high hydrogen production rates in a short time at lower temperatures, while intermediate temperatures of above 50 °C can accelerate the hydration reaction of the oxide layer. Herein, the mixture of NaOH and NaAlO2 catalysts was employed to attain a stable NaAlO2 solution and continuous reaction of NaOH and aluminum. This research analyzes the influence of temperature between 32 and 80 °C on the aluminum, 0.3 M NaOH and 0.001 M NaAlO2 catalysts solution at atmospheric pressure. All solutions produces a similar hydrogen yields and rate. Solutions containing NaAlO2 indicate reverse reaction that surpressing the Al(OH)3 precipitation. Residue from the reaction is investigated using X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), and Scanning Electron Microscope (SEM). The volume of hydrogen produced is evaluated using a mathematical mass reduction and shrinking core model. The rate of hydrogen production depends largely on the aqueous solution's temperature, with an activation energy of 47.4 kJ/mol. Based on the findings, it is readily apparent that the reaction only produced gibbsite and bayerite, with gibbsite and bayerite being dominant at 32–70 °C and 80 °C, respectively. The mass reduction model fits well with the present results with only an average 5.1 mL deviation, whereas the shrinking core model generally tends to result in underestimated values with an average deviation of 23.9 mL. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Joining of Polymer to Aluminum Alloy AA1050 By Friction Spot Welding

The friction spot welding process is used to join the hybrid joint of aluminium to polymer. AA 1050 Aluminum alloy and polyethylene polymer (type of plastic) were used for joining. Aluminium surface treatment was done to increase the wettability of it. The surface treatment was done by electrochemical treatment. Two parameters of the joining process were used: (1, 1.5 and 2) min. (920, 1340 and 1500) rpm for time and rotational speed, respectively. Many tests for the joint are done: shear test and Scanning electron microscopy (SEM). Using the Minitab program, the effect of the parameters on the joint was analysed. The maximum value of the shear force was (1587 N) at 1.5 min. time and 1340 rpm rotational speed. The minimum shear force was (589 N) at 1 min. time and 920 rpm rotational speed. The joints which were tested failed by an interfacial shear with a ductile fracture of the polymer side. The process of joining mechanism occurred through a mechanical interlocking between the molten polymer and the surface of the AA 1050 aluminium specimen, cohesive and adhesive. The average thickness for the joint of the tested specimens was 4µm.

Aluminum Surface Defect Detection Algorithm Based on Improved YOLOv5

AbstractIndustrial defect detection is an important aspect of object detection. Aluminum is an indispensable material in the industrial field, but the complexity of surface defects on aluminum makes detection challenging. Therefore, the paper proposes the YOLOv5‐ESP algorithm based on the YOLOv5 algorithm. First, the problem of poor signal quality and small data samples is addressed through data enhancement. Second, the YOLOv5‐ESP incorporates the Efficient Channel Attention‐C3 (ECA‐C3) module in the Backbone structure to enhance attention toward defect regions. The Spatial Pooling Pyramid Cross‐Stage Partial Convolution (SPPCSPC) module is introduced to extract multi‐scale features of defects. The Poly‐scale Convolution (PSConv) is applied at the end of the Neck structure to resolve the problem of imprecise localization resulting from significant differences in the scale of defect features. Soft Non‐Maximum Suppression (Soft‐NMS) is utilized in the Head structure to optimize the prediction boxes. Experimental results show that the proposed YOLOv5‐ESP achieves a mean Average Precision (mAP) value of 94%, outperforming YOLOv5 and other classical algorithms. Furthermore, it maintains an average recognition time of 0.019 s per image, which meets the requirements of accuracy and real‐time performance in the industry.

Elucidating the Effects of Chemisorbed Water Molecules on the Adhesive Interactions of Epoxy Resin to γ-Alumina Surfaces.

The adhesion mechanism of epoxy resin to the γ-alumina (110) surface was investigated using first-principles density functional theory (DFT). Aluminum materials are lightweight and are used in a wide range of industrial fields. Its surface is oxidized to alumina, and the stable surface is known as the γ-alumina (110) surface. The coverage of hydroxy groups by chemisorbed water molecules on this surface varied depending on the pretreatment temperature. In this study, we investigated the adhesive interactions of epoxy resin on four alumina surfaces with different densities of surface hydroxy groups (0, 3, 6, and 9 OH/nm2) and have discussed their effects. At each interface, the energy curves of the vertically displaced epoxy resin were calculated and the adhesive forces were estimated by differentiating these curves. As the coverage of the surface hydroxy groups increased from 0 to 6 OH/nm2, the adhesive strength gradually decreased. However, the adhesive strength at 9 OH/nm2 was relatively large and almost equal to that at 3 OH/nm2. This inverse volcano-type behavior was analyzed via the decomposition of adhesive forces and the crystal orbital Hamilton population (COHP). The decomposition of adhesive forces into DFT and dispersion components revealed that the inverse volcano-type behavior is derived from the DFT component, and the interfacial interactions owing to the DFT component are accompanied by charge transfer. These were investigated using a COHP analysis, which revealed that this behavior was caused by changes in the activity of the aluminum atoms on the surface and surface reconstruction by chemisorbed water molecules. It is noteworthy that the adhesive strength for 9 OH/nm2 was only 6.9% lower than that for 0 OH/nm2 wherein the chemisorbed water molecules were completely removed from the surface. These results are expected to provide a guideline for the adhesion of epoxy resin to aluminum materials.

Inhibition of corrosion of an aluminum alloy by rosemary and eucalyptus extracted oils in 1M hydrochloric acid medium: an experimental and theoretical study.

In this study, we explored aluminum corrosion inhibition field of study in a 1M HCl solution, harnessing the power of essential oils extracted from rosemary and eucalyptus plants. Our exploration gives a comprehensive analysis of the pivotal factors that shape the corrosion inhibition process. Our scientific journey was marked by a deliberate and systematic approach, encompassing the utilization of gravimetric analysis (weight loss), electrochemical potentiodynamic polarization, and the sophisticated electrochemical impedance spectrometry (EIS) techniques. Our findings unveiled promising and nuanced outcomes, particularly in the area of the electrochemical technique. This method demonstrated remarkable inhibition efficiencies, ranging from 42% to an impressive 92% for rosemary essential oil and from 37 to 84% for eucalyptus essential oil. These results unveiled a dynamic relationship between essential oil concentration and inhibition efficiency, a revelation that further deepens our understanding of the corrosion inhibition process. The inhibition efficiency increased with higher concentrations of essential oil but decreased with elevated temperatures. Furthermore, our analysis traversed into the realms of potentiodynamic and thermodynamic insights. These analytical techniques unearthed the complex mechanisms at play, explaining the pathway followed by the studied inhibitors. They exhibited their prowess by forming protective films on the metal surface, acting as vigilant protectors against the relentless forces of corrosion. Complementing our experimental findings, our study of computational chemistry through density functional theory (DFT) unveiled remarkable insights. It elucidated the spontaneous adsorption process of inhibitor molecules onto the aluminum surface in the presence of H2O solvent. This computational harmony with our experimental results strengthened our confidence in the robustness of our findings. One of the key findings of this study was the superior inhibitory power of camphor in rosemary EO and β-myrcene in eucalyptus essential oil EO, respectively, attributed to the distinctive characteristics of the active sites found in each compound. The inhibitory effectiveness followed the order β-myrcene > camphor > borneol > α-pinene > bornyl acetate > p-cymene > 1,8-cineole. These compounds, notable for their distinct active sites, emerged as exceptional agents in the pursuit of effective corrosion inhibition.

Research on the mechanism of the two-dimensional ultrasonic surface burnishing process to enhance the wear resistance for aluminum alloy

The gradient nanostructure is machined on the aluminum (Al) alloy by the two-dimensional ultrasonic surface burnishing process (2D-USBP). The mechanism of why the gradient nanostructure enhances wear resistance is investigated. The mechanical properties and microstructure characterization for the gradient nanostructure are performed by operating a nanoindenter, transmission electron microscopy (TEM), and electron backscattered diffraction (EBSD). Dry wear tests are performed on the samples before and after machining to evaluate the wear resistance and mechanisms. The effect of the gradient nanostructure on the wear resistance is explored by developing the crystal plasticity (CP) finite element and molecular dynamics (MD) models. The characterization results show that the 2D-USBP sample prepared a gradient structure of ∼600 µm thick on the aluminum surface, increasing the surface hardness from 1.13 to 1.71 GPa and reducing the elastic modulus from 78.84 to 70.14 GPa. The optimization of the surface microstructure and the increase of the mechanical properties effectively enhance the wear resistance of the sample, with 41.20%, 39.07%, and 54.58% of the wear scar areas for the 2D-USBP treated samples to the original samples under 5, 10, and 15 N loads, respectively. The gradient nanostructure hinders the slip of dislocations inside the sample during the wear process and reduces the size and scope of plastic deformation; meanwhile, the resistance to deformation, adhesion, and crack initiation and propagation of the sample surface is improved, resulting in enhanced wear resistance.

Size Dependence of the Adsorption Properties of Nickel Clusters on the Surface of Aluminum Oxide

Size Dependence of the Adsorption Properties of Nickel Clusters on the Surface of Aluminum Oxide

The Role of Alanine in the Chemical Mechanical Polishing of Aluminum

With the evolution of integrated circuits, the transition from polycrystalline silicon to aluminum as the gate electrode has become prevalent due to its inherent advantages. This study considers the impacts of pH, H2O2 and alanine on the aluminum removal rate and surface roughness during chemical mechanical polishing (CMP) with abrasive colloidal silica. Alanine was incorporated as a complexing agent in the polishing slurry in an acidic environment. The mechanistic role of alanine in the aluminum CMP process was investigated with various techniques, including electrochemical tests, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy (UV–vis). Additionally, density functional theory (DFT) calculations were used to examine the quantum chemical parameters of alanine and elucidate the complexation mechanism. The experimental results indicated that at an alanine concentration of 1.5 wt%, the Al removal rate was 2124.07 Å min−1 with a surface roughness of 1.33 nm. The interactions between alanine and the aluminum ions (Al3+) yielded soluble Al-alanine complexes, which facilitated corrosion on the Al and enhanced the removal rate.

Adsorption-induced transient friction of hydrogels on hydrophilic countersurfaces

Soft hydrated permeable surfaces of hydrogels exhibit unique lubrication behaviors, including frictional hysteresis found in tribo-rheometry measurements. A hydrogel lubrication model that describes the transient behavior was previously developed using the structure kinetics model in the field of rheology and rate-and-state friction model, where the friction change is described as a competition between buildup and breakdown rates. In this study, the model is further modified to include the effect of hydrophilicity of a countersurface. Ultraviolet (UV)/ozone treatment on an aluminum surface significantly removes organic materials, resulting in extremely hydrophilic surface. Friction response of a polyacrylamide hydrogel against untreated and UV/ozone-treated aluminum exhibited noteworthy difference in the trajectory of hysteresis. Model fits were conducted using the modified lubrication model on both hystereses, and the fitting parameters of both hystereses are compared with each other to identify a parameter addressing hydrophilicity. Based on the model fits, we suggest that the hydrophilicity of the countersurface initially prevents the adsorption on the hydrogel surface because it holds water better. However, once water goes out of the contact due to contact pressure, a stronger adsorption occurs, which increases friction and decreases the speed dependence of friction.

Assessment of Materials on Covid-19 Spread Prevention in Public Buildings

This research is an attempt to suppress the spread of COVID-19 in public buildings through the application of materials that may prevent the spreading of SARS-CoV-2 while at the same time improving audial comfort in such buildings. Study on the capability of materials to break further spreading of the virus applied by measuring the presence of SARS-CoV-2 RNA on the material based on exposure time (0, 3, 6, and 9 minutes). This RNA tracing procedure is repeated on the surface of aluminum, tiles, carbon steel, glass, gypsum, copper, and painted cement on the wall. The results showed that the CT value (cycle threshold) of all materials was approximately 25, which means that they still have the potential to spread the virus. Slightly different results occur on the gypsum surface where the viral envelope (gene E) is not detected with a CT value of 36, meaning no chance of the virus spreading. The same materials will undergo measurement of sound absorptive characteristics to assess their effect on the audial comfort in the building. The results of the study are expected to be a reference before their application as interior materials in public buildings.

An overview of hydrogen production from Al-based materials

Abstract A profound overview of the recent development for on-time, on-demand hydrogen production from light metal-based hydrolysis is presented. Hydrogen energy is one of the clean and renewable energy sources which has been recognized as an alternative to fossil fuels. In addition, aluminum is the most suitable light activity metal for hydrolysis materials attributed to its safety, environmental friendliness, high-energy density, inexpensive, and low density with high strength ratio. In general, dense oxide films formed act as a barrier on aluminum surfaces. Accordingly, effective removal of the oxide film is a key measure in solving the Al–water reaction. In this review, recent advances in addressing the main drawbacks including high-purity aluminum with acid–alkali solutions, nano-powders of aluminum or composite with acid–base solutions, ball-milled nano-powders, alloying blocks, and gas atomization powders are summarized. The characteristics of these three technologies and the current research progress are summarized in depth. Moreover, it is essential to promote low-cost aluminum-based materials based on effective hydrogen production efficiency and explore ways for practical large-scale applications.

A Superhydrophobic Anti-Icing Surface with a Honeycomb Nanopore Structure

Recently, the icing disaster of transmission lines has been a serious threat to the safe operation of the power system. A superhydrophobic (SHP) anti-icing surface with a honeycomb nanopore structure was constructed using anodic oxidation technology combined with a vacuum infusion process. When the current density was 87.5 mA/cm2, the honeycomb porous surface had the best superhydrophobic performance (excellent water mobility), lowest ice-adhesion strength (0.7 kPa) and best anti-frosting performance. Compared with other types of alumina surfaces, the ice-adhesion strength of the SHP surface (87.5 mA/cm2) was only 0.2% of that of the bare surface. The frosting time of the SHP surface (87.5 mA/cm2) was 150 min, which was much slower. The former is attributed to the air cushion within the porous structure and the stress concentration, and the latter is attributed to the self-transition of the droplets and low solid–liquid heat transfer area. After 100 icing or frosting cycles, the SHP surface (87.5 mA/cm2) maintained a low ice-adhesion strength and superhydrophobic performance. This is because the anodic oxidation process forms a hard porous film, and the nano porous structure with a high aspect ratio can store modifiers to realize self-healing. The results indicate that the SHP surface with a honeycomb nanopore structure presents excellent anti-icing performance and durability.

Identification of oxidized platinum single atoms on chlorinated γ–alumina support by density functional theory calculations and X-ray absorption spectroscopy

The existence and nature of oxidized Pt single atoms (SA) are unraveled on two γ-Al2O3 supported Pt catalysts (0.3 wt%) containing two chlorine contents (0.1 and 1.4 wt%) characterized by HR-HAADF-STEM and HERFD-XANES/EXAFS after a calcination treatment at 520 °C. Pt SA are revealed as PtOxCly complexes where the number of oxygen (x) and chlorine (y) ligands directly depends on the chlorine content. In order to interpret these experimental observations and provide coherent atomic structures for these PtOxCly complexes, the thermodynamic stability of the oxidized Pt SA species supported on the (100) surface model of γ-Al2O3 is determined by density functional theory (DFT) calculations as a function of the calcination conditions determined by the temperature, and partial pressures of H2O, HCl and O2. It is shown that various ligands such as Cl, OH, O (from the alumina surface or as extra-ligands) and H2O are coordinated to Pt depending on the conditions and chlorine content. Various square planar and square-based pyramidal PtOxCly species such as PtO2, PtOCl2, PtCl4 are found to be stable in calcination conditions, while octahedral Pt(OH)xCl4-x(H2O) are stabilized in XAS recording conditions. The features of these DFT simulated octahedral Pt SA species are successfully compared to XAS data. On one hand, based on thermodynamics arguments, we proposed models of supported complexes in agreement with EXAFS coordination numbers and distances (Pt-O, Pt-Cl and Pt-Al). On the other hand, the simulated XANES spectra at the Pt L3-edge for these complexes match well with the experimental HERFD-XANES and reveal that the bump feature observed between 11575 eV and 11585 eV (post-edge signal) is a tracer of the amount of Cl coordinated to Pt SA.

Characterization of Molecular Interactions in the Bondline of Composites from Plasma-Treated Aluminum and Wood.

Wood and aluminum composites are becoming increasingly attractive due to their ability to combine the advantages of both materials: the lightweight nature of wood and the strength of aluminum. However, using conventional wood adhesives like polyvinyl acetate (PVAc) to bond these dissimilar materials is challenging and requires special surface treatments. Prior studies have demonstrated that applying a dielectric barrier discharge plasma treatment significantly enhances shear and bending strengths in beech wood/aluminum bonds. This study focuses on the molecular interactions between PVAc and aluminum or beech wood influenced by plasma surface modification. Surface-sensitive methods, including X-ray photoelectron spectroscopy, infrared reflection adsorption spectroscopy and atomic force microscopy, were employed to characterize the PVAc films on the corresponding surfaces and to identify possible interactions. The ultrathin PVAc films required for this purpose were deposited by spin coating on untreated and plasma-treated aluminum. The aluminum surface was cleaned and oxidized by plasma. Additionally, hydroxyl species could be detected on the surface. This can lead to the formation of hydrogen bonds between the aluminum and the carbonyl oxygen of PVAc after plasma treatment, presumably resulting in increased bond strength. Furthermore, the beech wood surface is activated with polar oxygen species.

The roles of undercooling degree and materials surface configuration in the growth mechanism of ice layer caused by micro-droplets

Effect mechanisms of the undercooling degree and the surface configuration on the ice growth characteristics were revealed under micro-droplets icing conditions. Preferential ice crystals appear firstly on the surfaces due to the randomness of icing, and obtain growth advantages to form protruding structures. Protruding structures block the incoming droplets from contacting the substrates, causing voids around the structures. The undercooling degree mainly affects the density and the growth rate of preferential ice crystals. With the increase of undercooling degree, the preferential ice crystals have higher density and growth rate, resulting in stronger growth advantage and higher porosity. The surface configuration affects the growth mode, and the ice layer grows with uniform mode, spreading mode and structure-induced mode on the aluminum, smooth Polytetrafluoroethylene (PTFE) and rough PTFE surface respectively, causing the needle-like, ridge-like and cluster-like ice crystals. The rough structures effectively improve the porosity of the ice layer, which is beneficial for optimizing the icephobic property of the materials. This paper provides important theoretical guidance for the design of subsequent icephobic materials.

DFT , Monte Carlo and Molecular Dynamics modeling of the Carvacrol, Camphor and Linalool /Al(111) Interaction

In this work, the interaction of three natural compounds: carvacrol (Inh-1), camphor (Inh-2), and linalool (Inh-3) on the Al(111) surface have been studied using DFT/B3LYP/6-31G(d,p), to understand adsorption behavior on the metal surface. The results obtained show a strong correlation between the inhibitory efficiency (IE%) of aluminum corrosion and the quantum chemical parameters of reactivity derived from DFT. In addition, the interactions between the three natural inhibitors and the aluminum surface were studied using Monte Carlo (MC) and molecular dynamics simulations, as a result, the three molecules have strong interactions with the metal surface and thus have excellent predictive power for inhibition against metal corrosion, the three corrosion inhibitors have higher inhibitory efficiency and can be used as inhibitors to minimize the corrosion rate of the metal, therefore, the efficiency of Inh-1 is more important than the efficiency of Inh-2 and Inh-3.

Corrosion inhibition and Adsorption characteristics of 3,4,5-trihydroxy-n-(3,4-dimethoxy benzylidene) benzo hydrazide schiff base on aluminium in different concentration of Hydrochloric acid environment

In the present paper we are presenting our studies on the synthesis of Schiff bases typically formed by condensation of 3,4,5-trihydroxy benzohydrazide and 3,4-dimethoxy benzaldehyde by microwave induced irradiation, reaction showed enhanced yield and less time, easier workup. The characterization of synthesized compound has been done on the basis of elemental analysis, spectral studies (FTIR,1HNMR, Mass) and surface morphology by Scanning Electron Microscopic (SEM). The structural composition of synthesized compound has been determined by X-Ray diffraction (XRD). The inhibition property of Schiff base 3,4,5-trihydroxy –N-(3,4dimethoxy benzylidene) benzo hydrazide on the corrosion of aluminum in 0.5N HCl,1NHCl, 2N HCl were studied using weight loss technique and electrochemical studies revealed mechanistic aspects of corrosion inhibition like potentiodynamic polarization measurements indicated the nature of inhibitor is a mixed type and impedance studies supported the formation of a protective layer of inhibitor on a metal surface. Adsorption of the inhibition molecule on aluminium surface was consistent with the Langmuir isotherm.

Evaluation the Effect of Diazonium Salt and Aluminum Oxide on the Shear Bond Strength of Heat Cure Acrylic Resin at Co/Cr and Titanium Alloys Interface

Bonding between metal components and denture base resin plays an important role in the success of removable partial denture. Removable partial denture prostheses often present a mechanical failure. The bonding between metal framework and acrylic resin is usually a mechanical interlock, since they do not chemical bond spontaneously. The aim of this study was to evaluate the effect of different surface treatments (diazonium salt and aluminum oxide) on the shear bond strength of PMMA at the Co/Cr and titanium alloys interface. Sixty-disc shape specimens were prepared and divided into 2 main groups according to the type of material, 30 specimens for Co/Cr alloy and 30 specimens for titanium alloy, then subdivided into 3 groups each one consist of 10 specimens, according to type of surface treatments. Each group had control group, aluminum oxide group (110 μm), and diazonium salt group. The specimens were thermocycled (3000 cycles) after applications of PMMA. Shear bond strength test conducted with crosshead speed 0.5mm/min. Data analyzed via One-way ANOVA and GHD test. Co/Cr alloy revealed that diazonium salt surface treatment had highest mean value of shear bond strength followed by aluminum oxide surface treatment at p<0.01. For titanium alloy, the results showed the diazonium salt surface treatment had highest mean value of shear bond strength followed by aluminum oxide surface treatment group at p<0.01. Aluminum oxide treatment slightly increased shear bond strength for both Co/Cr and titanium, while diazonium salt treatment statistically increased shear bond strength for Co/Cr and titanium alloy.

Mechanisms controlling friction and material transfer in sliding contacts between cemented carbide and aluminum during metal forming

Cold forming of aluminum alloys is frequently associated with problems related to severe adhesion and material transfer onto the forming tools which results in high friction forces and negatively affects the surface quality of the formed parts, a phenomenon frequently named galling. In the present study, well controlled laboratory tests using a scratch testing equipment have been performed to evaluate the friction characteristics and investigate the mechanisms controlling the initial transfer of aluminum in dry sliding contact with five different cemented carbide grades. In the tests, an aluminum pin (representing the work material) with a conical tip slides against a flat, fine-polished, cemented carbide surface (representing the tool). During sliding, the mechanical contact results in plastic deformation and flattening of the work material against the tool surface, thus simulating a metal forming contact. The small scale and well-defined tribo contact in combination with post-test surface characterization using optical surface profilometry, high resolution SEM and EDS makes it possible to evaluate the influence of material transfer on the friction characteristics.The results show that sub-μm surface irregularities in the cemented carbide surface trigger mechanical interaction with the softer aluminum surface which promotes aluminum transfer to the cemented carbide surface resulting in high friction. Common surface irregularities, promoting aluminum transfer, are sharp edges of slightly protruding carbide grains, surface steps in connection to binder phase pockets, surface steps in connection to surface pores, etc. It should be noted that even very small surface steps, < 20 nm in height, constitute efficient cutting edges able to effectively cut off the passing aluminum material and thus have a very strong impact on material transfer. In contrast, the effect of carbide composition, e.g. the presence of cubic carbides of different composition, seems to be of minor importance to reduce the adhesion and the tendency to material transfer.