Effect Of Rare Earth Alloy A356 Performance Hub Of Automotive Aluminum Wheels

This paper was according to the current car aluminum wheel hub development trend and the needs of the production of the practice. We have studied that casting alloy A356adding RE (main ingredients for La and Ce) and Sr after the change of performance with the traditional casting process. Combined with single add on the performance of the alloy and the advantages and disadvantages of the change. We added RE and Sr to the A356alloy, in order to looking for a best match specific flow to changing the performance of the cast aluminum alloy. In the experiment process are analyzed about the RE and Sr interaction. In this paper, we used the metallographic microscope (OM), scanning electron microscopy (SEM), energy spectrometer (EDS) and universal tensile machine and other detection equipment. It analyzed the influence of the microstructure morphology and mechanical properties. The results show that:(1) Based on the Sr A356alloy add separate study found that, compared with the blank group eutectic silicon structure is obviously modification effect, from the original sheet and acicular change on thin fibrous and mesh. During the experiment, found that although the alloy eutectic silicon tissue is greatly improved, the mechanical properties have been improved, but the microstructure is not very ideal, the presence of a large number of pinholes, the mechanical properties of the alloy also has certain adverse effects.(2) By RE on A356alloy refinement, found when rare earth is added in the0.15%-0.45%between microstructure has better effect, relative to add Sr alloy have been greatly improved. After adding RE alloy mechanical properties improved, microstructure was refined, purified grain boundary clear tissue morphology of silicon phase, but did not change significantly, still show a patchy and needle-like, therefore the mechanical properties of alloy will be affected, increase as add Sr obvious.(3) In this paper through the United refining modification treatment, we found that RE and Sr on A356alloy has the comprehensive effect of the alloy at the same time, a combination of Sr modification, rare earth purification and refining alloy advantages, although the two join weakening their effect, but its excellent comprehensive mechanical performance, microstructure are the ideal effect. When the dosage of RE/Sr too much, the RE/Sr in the alloy can have certain interaction, form an intermetallic compound, thereby reducing the effective RE alloy, the content of Sr, weakening of refinement and modification effect, so that the mechanical properties of the alloy weakened.(4) In this experiment, heat treatment using conventional T6technology, A356alloy after treatment with T6, the morphology of silicon phase in the alloys become rounded, mechanical properties are increased. The refining and modification of the alloy after heat treatment after T6tensile strength more than200MPa, the mechanical properties meet the present German luxury cars with aluminum wheel mechanical properties than200MPa performance requirements, has a certain market value.(5) The experiment of A356alloy under different conditions were studied by conductivity, conductivity and thermal conductivity of the proportional relationship between indirect research, A356thermal conductivity, thus get alloy heat dissipation performance strength, make the aluminum hub alloy properties reach the optimum state.