| 5356 aluminium alloy is a kind of wrought aluminum alloys, used in preparation of aluminum alloy welding wires. 5356 aluminium welding wire is universal welding material, which is extensively used for sports apparatus, locomotive carriage, chemical pressure vessel, armary processing, shipbuilding, space industry, etc. There are mainly two problems in aluminium alloys used for welding wires in our country: (1) the purity and microstrutrure of aluminium alloys are poor, (2) the mechanical properties (especially plasticity) of aluminium alloys are not good enough, which affected subsequent processing. In this paper, melt treatment, homogenization process and effects of Ce on 5356 aluminium alloy were studied by means of optical microscope, XRD, SEM, EMPA, tensile test and reduced pressure test.Reduced pressure test.was used to investigate the effects of C2Cl6 and NH4Cl on degassing of 5356 aluminium alloy. Experimental results suggest that the measured density of the RPT specimen of tablet degassing using C2Cl6 is 2.5402g·cm-3, which is higher than the density of 2.4717g·cm-3 using NH4Cl. It indicates that C2Cl6 is more efficient. Filtering experimental results show that the capability of removing the impurity of ceramic foam filter is better than fiberglass mesh.On the basis of the previous research, the grain refinement effect of Al-5Ti-1B on 5356 aluminium alloy was reseached. The results show that the best effect is reached with the addition of 0.5wt% Al-5Ti-1B when the holding time is 5 minutes at 720℃.The microstructure of 5356 aluminium alloy and the distributions of the alloying elements in the alloy before and after homogenization treatment were studied. The suitale homogenization treatment is found to be 420℃×18h. Meanwhile, the diffusion kinetics of the alloying elements during homogenization treatment was studied, and a homogenization kinetic equation was deduced, which was consistent with the above-mentioned homogenization process.The effects of Ce on microstructure and mechanical properties of 5356 aluminium alloys were investigated. The results suggest that the addition of Ce could not only obviously purifiy the aluminium melt and refine the grains, but also modify the metallic compound. With the increase of Ce, Al3Mg2 compounds at grain boundaries become more discontinous and the quantity of spherical Al3Mg2 increase. The mechanical properties are improved as well. Potentiodynamic polarization tests show that the addition of Ce can improve the corrosion resistance because of the effect of Ce on the modification of Al3Mg2 and the corrosion resistance of rare earth-riched phases.
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