Because the partition coefficient is one of the most important parameters affecting microsegregation, the aim of this research is to experimentally analyse the partition coefficient in Al-Mg alloys. In order to experimentally measure the partition coefficient, a series of quenching experiments during solidification were carried out. For this purpose binary Al-Mg alloys containing 6.7 and 10.2 wt-% Mg were melted and solidified in a DTA furnace capable of quenching samples during solidification. Cooling rates of 0.5 and 5 K/min were used and samples were quenched from predetermined temperatures during solidification. The fractions and compositions of the phases were measured by quantitative metallography and SEM/EDX analyses, respectively. These results were used to measure the experimental partition coefficients. The resultant partition coefficients were used to model the concentration profile in the primary phase and the results were compared with equilibrium calculations and experimental profiles. The results of calculations based on the experimental partition coefficients show better consistency with experimental concentration profiles than the equilibrium calculations.

Creep age forming (CAF) is one of the novel methods in aerospace industry that has been used to manufacture components of panels with improved mechanical properties and reduced fabrication cost. CAF is a combined age-hardening and stress-relaxation that are responsible for strengthening and forming, respectively. This paper deals with the experimental investigations of mechanical and springback properties of Al-Zn-Mg Al alloy in creep forming process. Creep forming experiments have been performed at temperatures of 120oC and 180oC for 6-72 h. Results indicated that yield stress and hardness of creep age formed specimens increased with increasing forming time and temperature, simultaneously induced deflection by stress-relaxation increased. Incorporating spring back and mechanical properties, it can be found that the appropriate forming cycle was 180oC/24 h among all forming conditions. CAF Time increase to a certain extent increased mechanical properties. This can be attributed to presence of stress in CAF that causes the precipitates be finer because of creation more nucleation sites. Therefor the growth of precipitates, takes place at long time and postpones the decreasing of the yield stress.

Multilayered ceramic-metal composites were produced by solid state diffusion bonding of polycrystalline alumina and three Al alloys containing 1 to 2%Sr, 2% Mg and Mg + Si (5057 Al alloy). The multilayered structures were fabricated at 610°C under a compressive stress of 3 MPa for 2 hours in He-5%H atmosphere. The ceramic-metal interfaces were studied by SEM and TEM equipped with an energy dispersive spectrometer (EDS). Addition of 1 wt % Sr to Al promoted good adhesion, without producing any interfacial products, while the Al-2wt%Sr was poor in this regard due to the presence of dispersed Al4Sr, which is an intrinsic phase in the Al-Sr phase system. The Al-2%Mg alloy produced a continuous film at the interface, which was characterized as being MgAl2O4. Al alloys containing Mg and Si (5057 commercial alloy) produced not only the spinel structure (MgAl2O4), but another phase rich in Mg and Si (close to Mg2Si). These latter interfacial reaction products were not the intrinsic phases in Al-Mg alloys, but were reaction products at the Al2O3 –Al alloy interfaces.

In this study, Mg-Sn alloys were produced with the addition of Sn to Mg powder at di erent ratios through the Powder Metallurgy (P/M) method. A new mixing technique was used in the production to avoid the disadvantages of high reactivity speci c to Mg powders. The prepared powder mixtures were turned into components by processing through hot pressing. The produced components were characterized by density measurements, microstructure examinations, and mechanical tests. The density measurements were made according to the Archimedes principle. The microstructural characterization was performed by X-Ray Di raction (XRD) analysis, Scanning Electron Microscope (SEM) investigations, and Energy Dispersive Spectrometry (EDS) analyses. The hardness measurements and tensile tests were used for determining mechanical properties. Densities close to the theoretical density were obtained in the produced parts. XRD and SEM investigations showed that the components produced were composed of -Mg and Mg2Sn phases of the microstructure consisting of coaxial grains. The rising Sn content increased the amount of discrete Mg2Sn precipitates at grain boundaries, thereby ensuring higher hardness and strength values.