Engineering and Technology Journal

The present work encompasses the development of microstructure by using cooling plate casting process. This process consists of pouring the molten metal at temperature close to the liquidus line in an inclined cooling plate. The mould and the slope plate unit were manufactured by the researcher. Pouring temperature and inclination angles have effect on microstructure, tensile strength, and on the macro hardness for both Al-1.6%Mg, Al-0.46%Mg.
The following variables have been used in this work: pouring temperatures of (750,800,850ᵒC), tilt angles of (30ᵒ, 40ᵒ, 50ᵒand 60ᵒ), and Mg additive of (1.6%, 0.46%) with constant cooling length (380mm). Tensile results reveal that (750,800 and 850ᵒC) especially for (30ᵒ, 40ᵒ, 50ᵒ) for 1.6%-Mg, and 0.46%Mg have a high value. Vickers macro hardness has a gradual increasing value for Al-0.46%Mg, but for Al-1.6%Mg rheocast alloy it has a fluctuated value, the higher value is for small angles (30ᵒ, 40ᵒ, and 50ᵒ) and small value for high angle (60ᵒ).

This work is concerned to study effect of addition the cadmium and nickel on mechanical properties of Al-Zn-Mg alloy. Three alloys were prepared with addition cadmium and nickel (0.5%wt) for each one alloy and added the nickel and cadmium in form combined of percentage (1%wt), as well as to base alloy. The alloys were prepared by melting and pouring in metallic mold. Many inspection and tests have been done such as microstructure, hardness , tensile test and wear test. The results show that addition of cadmium and nickel improved the mechanical properties of Al-Zn-Mg alloy, where they increase the hardness ( from58.4 to 86.92 kgmm2), tensile strength (from 87 to 107 Mpa) ,yield strength(from 32 to54 Mpa), and decrease the wear rate(from28 to 15.6x10-7gcm) and ductility (from 12 to 8.5%) and microstructure refined .Effect of nickel was more than cadmium, while the addition of nickel and cadmium together improved on improvement the mechanical properties more in comparison with the others alloy.

This work investigates the effect of different media (0.1N of NaOH, H2SO4
and NaCl solution) on the polarization behavior of Al-Zn-Mg alloy and calculates
some of the corrosion parameters such as corrosion potential (Ecorr) and current
density (icorr), cathodic and anodic Tafel slopes (bc & ba), and the polarization
resistance (Rp) .
The results of the polarization resistance indicates that Al-Zn-Mg alloy have
resistance in slat solution higher than that observed in acidic and basic solution
respectively .
Also some of the mechanical properties like the hardness and wear were
measured. The results for hardness showed that the untreated alloy in the
experimental solutions had higher hardness than those which are treated in salt,
acidic , and basic solutions respectively .
While the results for the rate of wear at different sliding speeds showed that the
rate of wear for the samples that treated in basic solution higher than those for
samples which are treated in the acidic and salt solutions . Also the same results
were get when measure the rate of wear with different applying loads.