On The Solid Transformation Of Zn-40wt.%Al Alloy During Aging

The phase transformation of a Zn-40 wt pet Al alloy during aging was studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), etc. The supersaturated solid solution a's would decompose during aging, forming the cellular structure by the discontinuous reaction and tweed-like structure by the continuous reaction. GP zones were formed in continuous reaction through spinodal decomposition, then equilibrium structure formed following the formation of transitional phases a", or a'm and R. In cellular reaction, cellular structure would grow into non-coherent matrix, and reach stable lamella distance with branch mechanism and nucleation mechanisms. Usually, second cellular reaction occurs. Precipitate free zones of vacancy denuded type were found in the vicinity of the boundary and within grains. In this research. TTT curve had been drawn for ZA40 alloy, the changes in volume and hardness of alloy during aging were studied.