Effect Of Rheological Forming On Microstructure And Properties Of Al-Si-Fe-V Alloy

A380 aluminum alloy has the characteristics of good thermal conductivity,easy machining and good formability.The alloy contains a certain amount of Fe element,which forms a long needle-like iron-rich phase in the alloy,which causes stress concentration and reduces the mechanical properties of the alloy.In order to reduce the harmful effects of Fe on aluminum alloy,the influence of V element on the morphology of iron-rich phase was studied.The effects of ultrasonic vibration,stirring and extrusion on the mechanical properties of A380 aluminum alloy iron-rich phase and alloy were also studied.The results show that after adding V element,the microstructure of A380 aluminum alloy is refined to a certain extent,and the length of long needle-like ?-Fe phase is reduced.This is due to the formation of a kind of alloy in the alloy after the addition of V element.The irregular bulk Al Si VFe phase consumes a portion of the Fe element in the alloy.Under the conditions of as-cast and T6 state,the mechanical properties of the alloy first increase and then decrease.When V:Fe is 1:1,the mechanical properties of the alloy reach the maximum value.The tensile strength,yield strength and elongation are as-cast.The rates were 225 MPa,207MPa and 1.45%,respectively,which are 14.22%,18.97% and 11.54% higher than those without V.The tensile strength,yield strength,and elongation in T6 state are 244 MPa,226 MPa and 1.60%,respectively.When V was added,it increased by 8.93%,18.33%,and 30.08%,respectively.After applying ultrasonic vibration to the melt of A380 alloy containing 0.7%V,the microstructure of the alloy was significantly refined due to the cavitation effect and acoustic flow effect of ultrasonic vibration.The average length of ?-Fe phase decreased from 35?m to 26?m.The average length of the eutectic Si was reduced from 27 ?m to 20 ?m,and the tensile strength and elongation of the alloy were increased by 4.00% and 77.59%,respectively,compared to the alloy to which no ultrasonic wave was applied.After applying agitation to the melt of A380 alloy containing 0.7% V,the average length of the ?-Fe phase is reduced from 35 ?m to 26 ?m,and the average length of the eutectic Si is reduced from 27 ?m to 25 ?m.The tensile strength and elongation of the alloy.The rate was increased by 1.33% and 58.62%,respectively,without applying agitation.After applying a combination of ultrasonic/stirring to 0.7% A380 alloy,the average length of ?-Fe phase is reduced from 35?m to 20?m,and the average length of eutectic Si is reduced from 27?m to 18?m.Tensile strength and elongation of the alloy.The rate was 8.00% and 165.52% higher than that of the alloy without the combined action.After the ultrasonic/stirring effect is applied to the A380 alloy melt,the extrusion is formed.As the extrusion pressure increases,the microstructure refinement becomes more and more obvious.Under the as-cast condition,when the extrusion pressure is 400 MPa,? The average length of the phase is 5 ?m,the average length of the eutectic Si is 4 ?m,the tensile strength and elongation also reach the maximum value of 279 MPa and 5.87%,respectively.In the T6 state,when the extrusion pressure is 400 MPa,the tensile strength The elongation and elongation also reached a maximum of 295 MPa and 8.16%,respectively.