A disordered over-saturated solid solution obtained through quenching and having Co concentration 
is unstable reported to a ordered phase of the same chemical composition and decrease the free 
energy from the point S to point M through a ordering process without germination. The ordered 
homogeneous phase of Co composition from the M point is metallic. Thus the free energy decrease 
to F point through the germination of a ordered phase of C°, composition (which is in equilibrium 
with the disordered o solid solution of C%, composition), those transformations being mentioned too 
in other system of alloys, (6). 
In the Fig.3 are presented the characteristically microstructure of dislocation of some Al-8,6%At.Li 
samples which was deformed through compression at room temperature till a 1,9% grade of 
reduction after 3 minutes from quenching. The dislocation structure is typical for materials with slip 
plane 
If the section of 
sig Of resistiviiy, 
at low angles and 
sence of ordering 
„Variation of free PU 
Fig.3. The planar structure of dislocation on a crystal 
Al-8.6%At Li deformed after quenching. 
Between dislocation which apear in plastic deformation process and the precipitate which are 
present in oversaturation oi solid solution are reactions of interdependence. The hardening effect 
produced by 8 phase on underaged alloys is main owned to the hardening phenomenon through 
ordering. The shearing of ordered particle by pairs of dislocations in case of the alloys which are in 
the aging process leads to planar slip associated with a hard deformation. Extended deformation 
was observed on isolate slip plane in case of underaged alloys, as a consequence of local tempering 
produced by slipping processes. The local tempering owing to slipping is a common characteristic 
of alloys with one phase which present short distance order, but also of the alloys with domains 
with long distance ordering. In case of quenched and cold plastic deformation sample, Fig 3, the 
presence of planar slipping is a consequence of homogeneous ordered matrix, in time that volume 
fraction of 8” particle is small 
The addition of 0.5% Ti in the Al-Li-Cu alloys leads to the finishing of the structure and the 
improving of mechanical properties. In the Al-Li-Cu-Ti alloy it was observed a new phase of star 
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