Formation of intermetallic α-Al₁₅(Fe,Mn)₃Si₂ alloy Al-Si-Cu solidified in ferrous substrate

The present study evaluated the distribution of solute and the first formation of intermetallic α-Al₁₅(Fe,Mn)₃Si₂ during solidification of a multicomponent alloy aluminum. This undesired phase-α is unwanted in the manufacturing processes of aluminum alloys, such as the under-pressure injection. His primary training takes place under specific chemical compositions and depend on the amount of Fe, the Mn/Fe ratio and the cooling rate. This work was carried out melting and controlled solidification of an aluminum alloy Al-Si-Cu-Fe-Mn, seeking the conditions of formation of intermetallic-α. The test was conducted in a special device melting/solidification type 'outward' pilot scale (10-15kg) coupled to an array of Fe-C (substrate), simulating an industrial process. Solidified regions were evaluated by optical emission spectrometry, XRD, optical microscopy and scanning/EDS. There was intense formation of the intermetallic compound-α (sludge) and, associated with this, severe chemical segregation in the regions adjacent to the substrate. (author)