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B.j. Abdul Aleem - One of the best experts on this subject based on the ideXlab platform.
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Corrosion Resistance of a New AL 6013-20 SiC(P) in Salt Spray Chamber
Journal of Materials Engineering and Performance, 2000Co-Authors: Zaki Ahmad, B.j. Abdul AleemAbstract:Aluminum 6013 alloy (0.82Si, 0.95Mg, and 0.35Mn) is finding increasing usage in new aircraft designs, automotives, and structural applications due to its good stretch forming character in T4 Temper (solution heat treated and naturally aged to a substantially stable conditions) compared to alloy 2024 (4.4Cu, 0.6Mn, 1.5Mg, and balance Al) and Al6061 (Si0.51 to 0.71, Fe0.35, Cu0.15, Mn0.85, Mg0.15, 0.25Cr, 0.15Zn, and balanced Al).
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Corrosion resistance of a new AL 6013-20 SiC(P) in salt spray chamber
Journal of Materials Engineering and Performance, 2000Co-Authors: Zaki Ahmad, B.j. Abdul AleemAbstract:Aluminum 6013 alloy (0.82Si, 0.95Mg, and 0.35Mn) is finding increasing usage in new aircraft designs, automotives, and structural applications due to its good stretch forming character in T4 Temper (solution heat treated and naturally aged to a substantially stable conditions) compared to alloy 2024 (4.4Cu, 0.6Mn, 1.5Mg, and balance Al) and Al6061 (Si0.51 to 0.71, Fe0.35, Cu0.15, Mn0.85, Mg0.15, 0.25Cr, 0.15Zn, and balanced Al). The newly developed A1 6013 reinforced with 20 vol.% SiC(P) has a higher strength than its unreinforced counterpart. Whereas the corrosion behavior of A1 6013 has been reported in literature, there is no previous data on A1 6013 reinforced with SiC(P). A knowledge of the corrosion behavior of this alloy is crucial to its applications in aerospace, structural, and automotive industry. The first results of corrosion study of this alloy in 3.5 wt.% Na Cl in a salt spray chamber are presented. Three Tempers F (as fabricated), O (annealed), and T4 (age hardened and stabilized at room Temperature) of the alloy A1 6013-30 SiC(P) were exposed to environmental chamber in accordance with ASTM recommended practice. The corrosion rate of the alloy showed a decrease with increased exposure period and after 800 h of exposure no appreciable change in the rate of corrosion was observed. The lowest rate of corrosion (4.83 mdd) was shown by Temper T4 followed by Tempers F and O after 1200 h of exposure in the increasing order of corrosion rate. Fluctuations in the corrosion rate with time are related to the kinetics of growth and dissolution of Al(OH)_3 film, which was detected by fourier transformation infrared (FTIR) spectroscopy (FTIS). The film was composed of an inner compact layer and outer bulk layer dependent on the refreshment rate from the bulk solution. Micrograph examination by scanning electron microscopy (SEM) showed the presence of pits covered by aluminum hydroxide gel, which isolates the pit from the bulk solution. The acidic conditions of pits also cause intergranular attack. Pitting was observed to be less pronounced in Temper T4 compared to F and O Tempers, the former also showing the highest resistance to corrosion. The data generated predict promising application potential of this alloy in environment where resistance to corrosion is also a major consideration.
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Effect of Temper on Seawater Corrosion of an Aluminum-Silicon Carbide Composite Alloy
Corrosion, 1996Co-Authors: Zaki Ahmad, B.j. Abdul AleemAbstract:Abstract The corrosion behavior of annealed (O), as-fabricated (F), and naturally age-hardened (T4) aluminum alloy Al 6013 (UNS A96013) with 20 vol% silicon carbide in particulate form (SiC[P]) was investigated in 3.5 wt% sodium chloride (NaCl) and in Arabian Gulf water. Of the three Tempers, T4 showed the lowest corrosion rate (0.04 mpy and 2.61 mpy) in deaerated and aerated NaCl, respectively. The corrosion rate in seawater was slightly higher. Predominant forms of corrosion were pitting and intergranular corrosion. Formation of corrosion chimneys was observed. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and energy dispersive spectroscopy (EDS) showed intermetallic formation and the presence of a gelatinous film of aluminum hydroxide (Al[OH]3) of bayrite type. The higher corrosion resistance of the T4 Temper resulted from finer and more homogeneously distributed precipitates compared to Tempers F and O. In view of the the alloy's good corrosion resistance and outstanding ult...
Yucel Birol - One of the best experts on this subject based on the ideXlab platform.
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Reversion Treatment to Improve Bake Hardening Response of a Twin-Roll Cast 6016 Automotive Sheet
Materials Science Forum, 2007Co-Authors: Yucel BirolAbstract:Heat-treatable Al-Mg-Si aluminum alloys for automotive body panel applications are shipped and formed in T4 Temper while still formable and are subsequently given a bake cycle to increase strength by age hardening while the paint is cured. However, the hardening response during the rather short industrial paint-bake is impaired upon natural ageing after the solution treatment. It is thus essential to counteract the adverse effect of natural ageing on bake hardening. While this is often accomplished by an additional ageing cycle before the paint-bake treatment, reversion treatments ought to be used once substantial natural ageing has first taken place to improve the bake hardening response of a twin-roll cast 6016 sheet. The present work was undertaken to improve the paint bake response of a twin-roll cast 6016 sheet by employing reversion treatments before the paint-bake cycle. Reversion treatments between 200°C and 250°C was effective in improving the bake hardening response of the twin-roll cast 6016 sheet which, when processed without reversion, failed to meet in-service strength requirements with a rather poor bake hardening response of 35 MPa.
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pre aging to improve bake hardening in a twin roll cast al mg si alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Yucel BirolAbstract:Abstract Heat-treatable Al–Mg–Si aluminum alloys are increasingly used for automotive body panel applications. They are shipped and formed in T4 Temper while still formable and are subsequently given a bake cycle to increase strength by age hardening while the paint is cured. The industrial paint-bake treatment, however, is too short to fully exploit the age hardening potential of these alloys. Hence, the microstructure in the conventional T4 Temper must be modified by creating clusters that grow and readily transform into coherent precipitates upon paint baking. The present work was undertaken to improve the paint-bake response of a twin-roll cast 6016 sheet by employing artificial aging between the solution treatment and the paint-bake cycle. Pre-aging in a wide Temperature range (60–200 °C) was effective in improving the bake hardening response of the twin-roll cast 6016 sheet which, when processed without any pre-aging, failed to meet in-service strength requirements with a rather poor bake hardening response of 35 MPa.
Zaki Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Corrosion Resistance of a New AL 6013-20 SiC(P) in Salt Spray Chamber
Journal of Materials Engineering and Performance, 2000Co-Authors: Zaki Ahmad, B.j. Abdul AleemAbstract:Aluminum 6013 alloy (0.82Si, 0.95Mg, and 0.35Mn) is finding increasing usage in new aircraft designs, automotives, and structural applications due to its good stretch forming character in T4 Temper (solution heat treated and naturally aged to a substantially stable conditions) compared to alloy 2024 (4.4Cu, 0.6Mn, 1.5Mg, and balance Al) and Al6061 (Si0.51 to 0.71, Fe0.35, Cu0.15, Mn0.85, Mg0.15, 0.25Cr, 0.15Zn, and balanced Al).
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Corrosion resistance of a new AL 6013-20 SiC(P) in salt spray chamber
Journal of Materials Engineering and Performance, 2000Co-Authors: Zaki Ahmad, B.j. Abdul AleemAbstract:Aluminum 6013 alloy (0.82Si, 0.95Mg, and 0.35Mn) is finding increasing usage in new aircraft designs, automotives, and structural applications due to its good stretch forming character in T4 Temper (solution heat treated and naturally aged to a substantially stable conditions) compared to alloy 2024 (4.4Cu, 0.6Mn, 1.5Mg, and balance Al) and Al6061 (Si0.51 to 0.71, Fe0.35, Cu0.15, Mn0.85, Mg0.15, 0.25Cr, 0.15Zn, and balanced Al). The newly developed A1 6013 reinforced with 20 vol.% SiC(P) has a higher strength than its unreinforced counterpart. Whereas the corrosion behavior of A1 6013 has been reported in literature, there is no previous data on A1 6013 reinforced with SiC(P). A knowledge of the corrosion behavior of this alloy is crucial to its applications in aerospace, structural, and automotive industry. The first results of corrosion study of this alloy in 3.5 wt.% Na Cl in a salt spray chamber are presented. Three Tempers F (as fabricated), O (annealed), and T4 (age hardened and stabilized at room Temperature) of the alloy A1 6013-30 SiC(P) were exposed to environmental chamber in accordance with ASTM recommended practice. The corrosion rate of the alloy showed a decrease with increased exposure period and after 800 h of exposure no appreciable change in the rate of corrosion was observed. The lowest rate of corrosion (4.83 mdd) was shown by Temper T4 followed by Tempers F and O after 1200 h of exposure in the increasing order of corrosion rate. Fluctuations in the corrosion rate with time are related to the kinetics of growth and dissolution of Al(OH)_3 film, which was detected by fourier transformation infrared (FTIR) spectroscopy (FTIS). The film was composed of an inner compact layer and outer bulk layer dependent on the refreshment rate from the bulk solution. Micrograph examination by scanning electron microscopy (SEM) showed the presence of pits covered by aluminum hydroxide gel, which isolates the pit from the bulk solution. The acidic conditions of pits also cause intergranular attack. Pitting was observed to be less pronounced in Temper T4 compared to F and O Tempers, the former also showing the highest resistance to corrosion. The data generated predict promising application potential of this alloy in environment where resistance to corrosion is also a major consideration.
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Effect of Temper on Seawater Corrosion of an Aluminum-Silicon Carbide Composite Alloy
Corrosion, 1996Co-Authors: Zaki Ahmad, B.j. Abdul AleemAbstract:Abstract The corrosion behavior of annealed (O), as-fabricated (F), and naturally age-hardened (T4) aluminum alloy Al 6013 (UNS A96013) with 20 vol% silicon carbide in particulate form (SiC[P]) was investigated in 3.5 wt% sodium chloride (NaCl) and in Arabian Gulf water. Of the three Tempers, T4 showed the lowest corrosion rate (0.04 mpy and 2.61 mpy) in deaerated and aerated NaCl, respectively. The corrosion rate in seawater was slightly higher. Predominant forms of corrosion were pitting and intergranular corrosion. Formation of corrosion chimneys was observed. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and energy dispersive spectroscopy (EDS) showed intermetallic formation and the presence of a gelatinous film of aluminum hydroxide (Al[OH]3) of bayrite type. The higher corrosion resistance of the T4 Temper resulted from finer and more homogeneously distributed precipitates compared to Tempers F and O. In view of the the alloy's good corrosion resistance and outstanding ult...
Telmo Roberto Strohaecker - One of the best experts on this subject based on the ideXlab platform.
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a sub structural analysis of friction stir welded joints in an aa6056 al alloy in T4 and t6 Temper conditions
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007Co-Authors: C A W Olea, L Roldo, J Dos M F Santos, Telmo Roberto StrohaeckerAbstract:Abstract Friction stir welds in an Al-alloy AA6056 in T4 and T6 Temper were investigated in terms of grain structure, dislocation density and second phase particles at the different zones of the welded joint. These results were subsequently compared with the unaffected base material. The aim of this investigation was to understand the metallurgical phenomena controlling the microstructural evolution associated with the friction stir weld process for Temper condition. Major emphasis was placed on the evaluation of second phase particle formation and evolution at weld zones. The stir zone of the T4 Temper maintains the precipitation features of the base material, while for the T6 Temper, dissolution of thin precipitates occurs. The stir zone of post weld heat treated joints presented equiaxed grains fully covered of very thin precipitates randomly distributed along the matrix. These precipitates are about 2–10 nm in diameter. The remaining regions are characterised by partial dissolution and precipitate coarsening during the FSW process.
Rolf Sandström - One of the best experts on this subject based on the ideXlab platform.
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influence of welding speed on the fatigue of friction stir welds and comparison with mig and tig
International Journal of Fatigue, 2003Co-Authors: Mats Ericsson, Rolf SandströmAbstract:Abstract The objective of this investigation was to determine whether the fatigue strength of friction stir (FS) welds is influenced by the welding speed, and also to compare the fatigue results with results for conventional arc-welding methods: MIG-pulse and TIG. The Al–Mg–Si alloy 6082 was FS welded in the T6 and T4 Temper conditions, and MIG-pulse and TIG welded in T6. The T4-welded material was subjected to a post-weld ageing treatment. According to the results, welding speed in the tested range, representing low and high commercial welding speed, has no major influence on the mechanical and fatigue properties of the FS welds. At a significantly lower welding speed, however, the fatigue performance was improved possibly due to the increased amount of heat supplied to the weld per unit length. The MIG-pulse and TIG welds showed lower static and dynamic strength than the FS welds. This is in accordance with previous comparative examinations in the literature on the fatigue strength of fusion (MIG) and FS welds. The TIG welds had better fatigue performance than the MIG-pulse welds. The softening of the alloy around the weldline has been modelled. Using a model without adjustable parameters, a fair description of the hardness profiles across the weld as a function of welding speed was obtained. The softening in front of the Friction Stir Welding tool was also estimated. At the low and high welding speeds a full and partial softening is predicted, respectively.
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Fatigue of friction stir welded AlMgSi-alloy 6082
Materials Science Forum, 2000Co-Authors: Mats Ericsson, Rolf SandströmAbstract:Results from tensile and fatigue testing of friction stir welds of the hardenable Al-Mg-Si alloy AA6082 are presented. The material was welded in the T6 and T4 Temper conditions. The T4 material was subjected to a post weld ageing treatment (PWAT), which enhances yield and tensile properties to basically those of the base material in the T6 condition. For T4 + PWAT the fatigue strength is lower than for T6, and with a steeper slope of the stress-life curve. The lower fatigue strength for the statically stronger T4 + PWAT material was unexpected. Fracture in T6 was initiated and propagated in the vicinity of the weak weld/HAZ border, at the stirred up edge on the shear side of the weld. For T4 + PWAT many fractures were at the shear side of the weld area.