F. M. Moghimi Ahouie - Department of Engineering, Saveh Branch, Islamic Azad University, Saveh, Iran
M. Emamy - School of Metallurgy and Materials, University of Tehran, ۱۱۳۶۵-۴۵۶۳, Tehran, Iran
A. Sedghi - Imam Khomeini International University, Qazvin, Iran
A. Hajaghassi - Department of Engineering, Saveh Branch, Islamic Azad University, Saveh, Iran

Because of special interfaces between matrix and reinforcement, in-situ composites have special microstructure and properties. This behaviour makes them attractive for different materials engineering research fields. On the other hand, presence of Lithium in Aluminium alloys introduces different behaviours in these alloys. In this paper, Mechanical properties of Al-Li alloys reinforced by in situ Mg2Si particles and different amount of zinc were investigated. Different amounts of Zn were added to the composite, then samples were cast, homogenized and extruded at 480°C at extrusion ratio of 18:1. Microstructure and mechanical properties of fabricated samples were studied by standard methods in order to find the effect of In situ reinforcement, Zn modifying agent as well as fabrication method on the Al-Li alloy morphology and behaviour. The results showed that zinc addition and homogenizing treatment were highly effective in modifying morphology of Mg2Si reinforcements. The results also exhibited that the addition of optimum amount of Zn will increase ultimate tensile strength (UTS) of In-situ composites drastically.

composite; hot extrusion; modification; ultimate tensile strength