Effect Of Semi-solid Processing On Cu Element Segregation Of Cu-containing Aluminum Alloy

Aluminum has excellent processing performance, widely used in industrial production.Cu element as hard strengthening phase, is often added to the Al alloy in order to obtain betterperformance. As an important technology machining alloys, semi-solid processing technologycombines the strengths of coagulation and plastic processing. But Al alloy uneven distributionof Cu in semi-solid process, the phenomenon is not conducive to improving the performanceof the alloy.How to theoretically understand the processing of semi-solid melt segregation ofalloying elements, which has practical significance to the preparation of the alloy.This was prepared by using electromagnetic stirring Al-4Cu alloy and Al-17Si-4Cu ally,copper distribution from electromagnetic stirring process of different aluminum-copper alloyand Al-17Si-4Cu ally was observed and analyzed. In the secondary heating process, thedistribution of copper was studied.The experimental results show that for Al-4Cu alloy， after electromagnetic stirring, Cuaggregated at the grain boundaries, the greater the magnetic field strength, aggregation of Cuelements is more obvious,and the degree of Cu aggregation is different at different position ofbillet.But for Al-17Si-4Cu alloy, electromagnetic stir makes primary silicon of Al-Si-Cu alloydissolve in the matrix and also prompts the eutectic Si phase refinement. This influencebecomes more obvious with the increase of electromagnetic stir intensity. In addition,electromagnetic stir can improve the segregation phenomenon of Cu element in Al-17Si-4Cuand make it distributed evenly. Cu element distribution becomes more and more homogeneouswith the increase of electromagnetic stir intensity.Reheating remelting can change the distribution of Cu in the semi-solid billet in whichthe degree of change is relevant to the fraction of remelting liquid volume. When the volumefraction of remelting liquid is higher,the distribution of Cu element will be uniform at theremelting zone;reheating remelting eventually expand the differences of Cu average content atremelting zone and non remelting zone.