MONDAY PM
2:20 PM Initial Studies of 6082 Aluminium Thin Films: Jon Holmestad1; Øystein Dahl2; Sigmund Andersen2; Oddvin Reiso3; Randi Holmestad4; John Walmsley2; 1NTNU / Hydro Aluminium; 2SINTEF; 3Hydro Aluminium; 4 NTNU The microstructure of thin aluminium 6082 films, with a thickness from 0.1 \956m to 1.6 \956m, has been investigated. The films were deposited by sputtering on Si <100> substrates. The resulting microstructure was studied using Scanning Electron Microscopy and Transmission Electron Microscopy. The grains grew columnarly and depending on the growth conditions, the diameter variedfrom 30 to 100 nm. Heat treatment at 773 K for 4 h was performed as an attempt to increase the grain size, but no subsequent grain growth was observed, indicating that the grain boundaries are stable. After deposition, several different ageing temperatures ranging from 423K to 573K and varying ageing times from 0.5 h to 10 h were performed. No precipitation was observed in the films, which could be due to the small grain size which is in the order of the precipitation free zone. 2:40 PM High Dense RF-DC Plasma Nitriding of Al-Cu Alloys: Tatsuhiko Aizawa1; Yoshio Sugita2; 1Shibaura Institute of Technology; 2YSElectronics, Co. ltd. Aluminum alloys have been used as structural components with aid of surface treatment. Although the conventional anodizing plays a role, there are many limitations in practice; i.e. insufficient wear toughness, low thermal conductivity and so forth. Our group has been concerned with plasma nitriding various kinds of aluminum alloys. In the present paper, Al-Cu based alloys in the class of A2012 and A2014 are employed to make high dense RF-DC plasma nitriding. Being different form the conventional RF or DC plasma nitriding, wide range of plasma ignition conditions are controlled to select the optimum processing step for low temperature nitriding. XRD and XPS analyses are utilized together with SEM and TEM to characterize the microstructure of plasma nitrided materials. Hardness and tribological testing is also used to describe their mechanical properties. Their applications to automotive parts and heat sink units are discussed on the above basic data. 3:00 PM Break
Technical Program
3:20 PM Cancelled Production of Nanostructured Coatings and Composite Layers on Aluminum Surface: Sergey Romankov1; Sergey Komarov2; 1Chonbuk National University; 2Nippon Light Metal Co. Ltd
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3:40 PM Corrosion Resistance Improvement by Alodine EC2 Coating on Aluminum Alloys: Jianhui Shang1; Steve Hatkevich1; Larry Wilkerson1; 1 American Trim LLC A new coating has been developed by Henkel Corporation for aluminum that could greatly increase the corrosion and wear resistance. This coating, called Alodine EC2, is electrodeposited from the electrical assisted hydrolysis of metal complexes, and provides superior resistance for harsh and demanding applications such as marine and high temperature engine environments against corrosion and wear. This paper will present the mechanism of Alodine EC2 coating on aluminum alloys, and the experiment results on the corrosion resistance improvement by Alodine EC2 coating. 4:00 PM Finite Element Simulation of Shot Peening: Prediction of Residual Stresses and Surface Roughness: Alexandre Gariepy1; Claude Perron1; Philippe Bocher2; Martin Lévesque1; 1École Polytechnique de Montréal; 2 École de Technologie Supérieure Shot peening is a surface treatment that consists of bombarding a ductile surface with numerous small and hard particles. Each impact
creates localized plastic strains that permanently stretch the surface. Since the underlying material constrains this stretching, compressive residual stresses are generated near the surface. This process is commonly used in the automotive and aerospace industries to improve fatigue life. Finite element analyses can be used to predict residual stress profiles and surface roughness created by shot peening. This study investigates further the parameters and capabilities of a random impact model by evaluating the representative volume element and the calculated stress distribution. Using an isotropic-kinematic hardening constitutive law to describe the behaviour of AA2024-T351 aluminium alloy, promising results were achieved in terms of residual stresses.
Forming and Joining 1
Program Organizers: William Cassada, Alcoa Technical Center; Hasso Weiland, Alcoa Technical Center; Anthony Rollett, Carnegie Mellon University Symposium Organizers: Kaan Inal, University of Waterloo; Raj Mishra, General Motors Inc. Monday PM June 4, 2012
Room: Rangos II Location: University Student Center
Session Chair: Jeong Whan Yoon, Swinburne University 1:20 PM Correlation of Fracture Behavior with Microstructure in Friction Stir Welded, and Spin-formed Al-Li 2195 Domes: Wesley Tayon1; Marcia Domack1; Stephen Hales1; 1NASA Langley Research Center Single-piece, spun formed domes manufactured from friction stir welded (FSW) plates of Al-Li alloy 2195 can significantly reduce the mass and cost of cryogenic tanks. In this study, the microstructure and texture transformations in the thermo-mechanically affected zone (TMAZ) are correlated with fracture behavior in the vicinity of the weld nugget. The texture transformation in the TMAZ is caused primarily by shear deformation during the FSW process. Variations are correlated with manufacturing parameters and linked with deformation, recrystallization, and shear texture components. Grain morphology and microtexture characteristics were examined in relation to spatial proximity to the weldment/parent metal interface. A strong correlation between fracture location and texture banding was observed. Fracture appears to follow a distinct region of low Taylor factor grains linked with texture bands. Modification of processing parameters to reduce the degree of heterogeneity in texture should lower the probability of fracture within TMAZ regions. 1:40 PM Effect of Process Parameters on Microstructure Stability of FSW Butt Joints after Thermal Treatments: Emanuela Cerri1; Paola Leo1; 1 University of Salento Friction Stir Welding process introduces a degree of deformation in the material that is related to process parameters. Rotational and transversal speeds directly regulate the heat input of welding process and then the morphology and microstructure characteristics. In the present work, mechanical properties and microstructure stability of FSW 6082T6 butt joints were investigated after exposure to high temperature. The thermal stability of fine recrystallized grains in the nugget zone depends on process parameters and post-welding heat treatment and it has unusual consequences on mechanical properties. Infact, ductility of the FSW joints increases with no decrease in strengths and hardness profile of the whole joint are homogenised. The effect of aging after cold deformation is also examined in FSW butt joints.