Study Of Iron-rich Phase Of A356 Aluminum Alloy Automobile Hub

Aluminum–silicon alloys are now being employed with growing frequency in the automotive industry. Especially, aluminum–silicon alloys are widely used in the manufacturing of automobile hub. The extended application of these alloys for automotive components has created the need for a more in-depth understanding of the effects of Fe content on the microstructure and property of the cast alloy. However, at present the research on the iron-rich phase of A356 alloy is only limited to specific conditions, changing the iron-rich phase morphology required the content of iron has not been determined, the morphology of the iron-rich phase with the content of iron in the relationship has not touched.In this paper the A356 alloy used in Qinhuangdao Daika Lida Machinery Co., Ltd was used as a base material and the different amounts of Al-Fe master was added in order to change the iron-rich phase morphology, preparation of A356 alloy ingots. The morphology were observed using MS software simulation and theoretical analysis of the effect of Fe content and the hub wheel type on the iron-rich phase morphology of the A356 alloy; And the sources of the Fe element in the alloy have been analyzed. The phases composition of the A356 alloy with different Fe content were analyzed by X-ray diffraction; The iron-rich phase morphology of the A356 alloy with different Fe content were studied by optical microscopy and scanning electron microscopy(SEM); Determine the relationship between the Fe content and the mechanical properties of the A356 alloy through tensile tests method.The results showed that 0.5wt% Al-5Ti-1B, 0.5wt% Al-10 Sr and different amounts of the Al-Fe alloy were added When the A356 alloy was melted at 740°C, and incubated for 10 minutes, a coarse acicular the β iron-rich phase has a considerable part transformed into a Chinese script(or Fishbone-like) α-iron phase, and the quantity of change also increases with the decreased of the Fe content, the β iron-rich phase transformation rate was up to 95.17% when the reduced Fe content is 0.2 wt%, the length and width of the acicular β-Fe phase,respectively, compared with the high level of Fe alloy was reduced by 44.13% and 43.89% when the Fe content is 0.6%; The alloy wheels cast need high temperature treatment, so the part of iron-rich phase of the A356 alloy was fused. The morphology of β-Fe phase have changed after high temperature treatment. The length and width of β-Fe phase tend to a fixed value. Coarse acicular iron rich phase occurred fuse phenomenon. After heat treatment, the acicular iron rich phase translate to granular iron rich phase.The tensile test results showed that, the ductility and the tensile strength reaches a maximum when decrease Fe content to 0.6%, and The further reduce of Fe did not affect the mechanical properties obviously, include ductility and tensile strength of the alloy.