Effect of Squeeze Casting on Microhardness and Microstructure of Al-3Cu-xSi Alloy

Abstract

Aluminum alloys of the ANSI series 319 present Si and Cu as the main alloying elements and the mechanical strength of these alloys can be improved by the precipitation of the metastable Al 2 Cu phase. Squeeze Casting is a casting process in which the cast metal is deposited in a metal mold and solidified under certain pressure exerted by a punch. This process provides changes in the microstructure which lead to changes in the mechanical properties of the material such as the increase in the microhardness of the processed alloy. alloys Al-5,5% Si-3% Cu, Al-7,5% Si-3% and Al-9% Si-3% Cu alloys were solidified by the squeeze casting process to analyze the microstructural and microhardness variations. Pressures of 0 MPa, 50 MPa, 100 MPa and 150 Mpa were used. In general, with increasing pressure and composition, the λ 2 values decrease from the metal/mold interface, especially at pressures of 150 MPa and Composition of 9%Si, on the other hand the increase of these variables leads to the formation of more phases Al 2 Cu metastable that have a decrease in the Microhardness of the material, in addition to the formation of other phases due to the proximity to the eutetic.

Squeeze casting for metal alloys and composites: An overview of influence of process parameters on mechanical properties and microstructure

“…Extreme high temperature results in coarse grain structure and excessive pressure causes particle damage, leading to reduced hardness [111] . Studies revealed that the addition of Sn to Mg/HA composites and the increase of Si concentration in Al-Si-Cu alloy resulted in an increased hardness [59,112] . A key consideration for improved hardness is the homogeneous distribution of the alloying and reinforcing phases in the matrix.…”