Abstract. This work represent an attempt to investigate the possible improvement to replace
(Cu) by (Li) in (Al-Cu) alloys used in aerospace industries. It is well established that (Al-Li)
alloys are attractive for military and aerospace application because their properties are
superior to those of congenital (Al) alloys. (Li) reduced the weight of the plane; hence, more
speed can be attained. Several other improvements are also intruded. Alloys were prepared
during this work by casting .they include (Al-Li-Cu-Mg-Zr), (Al-Li-Cu-Mg-Zr-Ag), and
(Al-Li-Cu-Mg-Zr-Ag-Ge) alloys. Result showed that addition 0.35%Ag to Al-Li-Cu-Mg-Zr
alloy improve strength from (42MPa) to (127MPa) when aging at 175°C.and improve
hardness from (156.64 Hv) to (173.74Hv) At the same temperature. But the deterioration
when addition 0.2 Ge to Al-Li-Cu-Mg-Zr alloy weakness strength from (127MPa) to
(26MPa) at the same time improved hardness from (156.64Hv) to (171.76Hv) at the same
temperature. Optical microscopy (OM),X-ray diffraction (XRD) were done to study the
structure and the surface features and chemical composition of the alloys. Many phases
shown which have an influence on the mechanical and chemical properties, such as (Al3Li),
(Al3Zr), (Al2MgLi), omega (Ω) precipitates, (Ag2CuLi), (Ge4Zr5).Pin-on-disc testing
technique was commonly used for investigating sliding wear. B significant increase in wear
resistance of the alloy. The weight loss was only 60% of the other alloy
ايناس ليث علي | Aenas Laith Ali | 8719