Papers by Keyword: Al-Mg-Si-Cu Alloy

Abstract: Welding properties of three alloys with different Cu contents (0.1, 0.4 and 0.9 wt.%) is studied by means of melt inert-gas welding (MIG). The results showed that, with the increase of Cu content from 0.1 wt.% to 0.9 wt.%, the strength and elongation increased obviously. When the Cu content was 0.9 wt.%, the strength and elongation reached 375MPa and 15%, respectively, which is a better match for bearing structure part of vehicles application. Besides, the adding of Cu element provided an increase limit for welding joint strength. Due to abundant coarse phases in fusion zone (FZ) and welding zone (WZ), the strength slightly increased and the failure fracture was different compared with that of 0.1Cu and 0.4Cu alloy. Present result was meaningful and valuable for pushing aluminum application automobile structural parts and other engineering components.

Abstract: A Zn-added Al-Mg-Si-Cu alloy during aging at 170 °C up to 34 h exhibits an interesting age-hardening effect. Small clusters, enriched in Mg and Si, are present in the sample after 0.25 h aging. The β′′ phase is dominant with the peak hardness of 135 HV after aging of 8 h. A decrease in hardness of the alloy occurs with the aging time increasing to 34 h, due to the coarsening of β′′ phase. It is also found that the Cu-containing L phase co-exists with the β′′ phase at this aging condition. The quantitative solute concentrations of the matrix show that the formation of clusters is consistent with the slight lower contents of Mg, Si and Cu compared with the alloy chemical composition, and the present of β′′ and L phase is associated with the further partitioning of Mg, Si and Cu from the Al matrix into the precipitates. No Zn-rich clusters and precipitates are observed and the Zn concentration in matrix has no significant change during aging for up to 34 h. This result means that the major of Zn remains in the matrix as aging continues.

Abstract: The evolution of through-thickness strain gradients during snake rolling (SR), which introduces an horizontal offset between upper and lower rolls, of Al-Mg-Si-Cu sheets was investigated with the inscribed lines in side including rolling and normal direction of sheets. The complete pole figures were used to investigate the influence of such rolling on texture evolution. The results revealed that the SR rolled sheet developed a continuous through-thickness shear strain gradients and shear textures. The surface in contact with the slower roll (the lower roll) developed the largest shear strain and the strongest shear texture. While for the conventional symmetric rolling (CR), the sheet developed a small shear strain gradient which is symmetrical about the centerline of the sheet with nearly negligible shear strain and texture at the center of the sheet.

Abstract: A new Al-Mg-Si-Cu aluminum alloy was hot compressed at temperatures between 320°Cand 530°Cand strain rates between 0.001 s¹ and 10 s¹ using a Gleeble-1500 thermo-simulation machine. The effects of deformation heating on flow stress were analyzed and corrected, and a comparison was made of hyperbolic-sine constitutive equations with and without correction. The results show that the deformation heating apparently increases the flow stress at strain rates of 1 s¹, 10 s¹. The thermal activation energy values were 325.12 KJ/mol and 304.47 KJ/mol before and after correction, respectively.

Abstract: In order to improve formability, it is practicable to control the texture through adjusting process parameters. This work describes the evolution of microstructure and texture during thermomechanical processing of Al-Mg-Si-Cu alloy. With the change of deformation conditions, both the microstructure and texture change dramatically. After hot rolling from 90 mm to 7.5 mm, H and E texture components in the surface layer become dominant due to non-uniform deformation. And then with the increasing of cold rolling deformation from 7.5 mm to 4.0 mm, the texture components gradually change from shear texture to typical fcc texture, i.e. Copper, S and Brass textures, and their intensities also increase. And these texture components transform to some uncommon texture components after intermediate annealing, including {013}<001>, {001}<130>, Goss texture, {556}<110> and {111}<110> texture, not as the typical recrystallization texture components. Continually giving a cold rolling deformation from 4.0 mm to 1.0 mm, not only Copper, S, Brass textures, but also Goss texture due to the lower deformation can be found in the alloy sheet. The high temperature solid solution treatment can result in the complete recrystallization and the formation of recrystallization texture, Cube, Goss and R texture, which results in the high formability of experimental alloy.

Abstract: The morphology of Si phase and its growth manner in the Al-Mg-Si-Cu alloys with amounts of excess silicon were investigated using by a combination of the higher magnification microstructure and DSC measurements. Solidification characteristics of the alloys were predicted by thermodynamic calculation and compared to the experimental results. It was found that addition of higher amount of excess silicon led to the formation of the evidently morphological Si phase, especially when the silicon content was beyond 1.35 wt.%. The Si phase was one of the dominant phases in the alloys and its reaction peak was identified with the onset temperature of 550.43oC in the DSC curves. These experimental results were in good agreement with the thermodynamic calculations by the Gulliver-Scheil model. Keywords: Al-Mg-Si-Cu alloy; morphology; thermodynamic calculation; excess Si

Abstract: The new Al-Mg-Si-Cu aluminum alloy has been developed for application in cold and hot extrusion and forging. Its nominal composition is 1.37%Mg、0.85%Si、0.82%Cu、0.11%Cr and 0.15%V. In this paper, The hot deformation behaviors of the new Al-Mg-Si-Cu aluminum alloy were studied by means of compression deformation tests on MMS-200 multifunctional materials simulation machine at strain rates ranged between 0.1~0.5s^-1 and deformation temperature between 350~550°C. The laws of the flow stress dependent both on thedeformation temperature and strain rates were discovered, and then the relationship between the first peak-stress σ_p and strain rates was obtained through one-dimensional linear regression.

Abstract: The over-burnt temperature of a new Al-Mg-Si-Cu Aluminum alloy was studied by means of DSC and microstructure analysis, as a result of the homogenization temperature being obtained. A favorable homogenization time was got by the way of the dependence of area fractions of remnant phases on homogenization time being calculated. According to experimentation results, the over-burnt temperature of the new Al-Mg-Si-Cu Aluminum alloy was 570°C, and the way to homogenize the new alloy at 560°C for 24h was excellemt.

Abstract: Small amounts of Mn have been used in order to modify the microstructure and thus improve the properties of the alloys. The effect of Mn addition on structure and properties of cold rolled Al-Mg-Si-Cu alloy at different annealed temperatures is presented in this paper. Both recrystallization temperature and activation energy of recrystallization are obtained from the hardness-temperature curves. The results show that Mn can have an inhibitive effect on recrystallization. Within a certain concentration of Mn in the alloy (<0.7 wt.%) both the activation energy of recrystallization and recrystallization start temperature increase with the addition of Mn content. The activation energy of recrystallization of the alloy which contains 0 wt.% Mn, 0.3 wt.% Mn and 0.7 wt.% Mn are respectively 134.4 kJ·mol-1, 137.4 kJ·mol-1 and 140.1 kJ·mol-1 and the recrystallization start temperature increases from 190 to 230 as Mn content increases from 0 to 0.7 wt.%.

Abstract: The kinds, morphologies and distributions, enclosed the micro-structural evolvement of Al-1.5Si-1.1Mg-0.5Cu alloy during homogenization treatment were investigated by means of optical microscopy, XRD, SEM/EDS and TEM/EDS. The results show that there were mainly three kinds of morphologically distinct constituents in as-cast Al-1.5Si-1.1Mg-0.5Cu alloy for automotive panels, such as coarse Mg2Si and Al8(FeMn)2Si, and multiphase eutectic structure consisted of AlMgSiFeCu elements, except the α-Al matrix phase. The coarse Mg2Si and Al8(FeMn)2Si were distributed in the α-Al interdentritic regions or at grain boundaries, the former sometimes appears more obvious eutectic characteristics than the later one. The multiphase eutectic products distributed both inside grains with agglomerate aspects and along the α-Al interdentritic regions or at grain boundaries, which is contained with Si and Al2Cu. Coarse binary eutectic structure Mg2Si partly dissolved into matrix and the eutectic characteristics disappeared, whereas Al8(FeMn)2Si changed a little during homogenization. Agglomerate multi-eutectic structures were non-equilibrium products, some of them fully dissolved into matrix and the others partially dissolved and left the discrete blocky Si behind after homogenization.