The Effect Of (Pr+Ce) On The Microstructure And Properties Of ZL105 Alloy

Aluminum alloy has been widely used in manufacturing as the structure of the traditional material.But the aluminum alloy crystallization structure are bulky and uneven after melting and casting,which are used as the billets of plastic processing.Due to the poor ultimate tensile strength and plastic property,the alloy can't match the requirement for application.Therefore,in order to achieve the as-cast organization and performance requirements in alloy,this article has studied the rare earth alloy processing by master-alloy.The results have shown that primary ?-Al distributes more uniform and orderly,the second dendrite arm spacing becomes smaller obviously.Moreover,the long needle-like eutectic silicon and fish-bone ?-Fe phases were transformed into round particles and short-rod shape in ZL105 alloy with 0.6wt.%(Pr+Ce)addition,respectively.There are rare earth phases(Al11Pr3 and Al11Ce3)generated,which have the high melting point and hardness.This rare earth strengthening phases can effectively improve the mechanical properties of Zl105 alloy.The alloy with 0.6wt.%(Pr+Ce)exhibited mechanical properties with hardness(87.96HV),tensile strength(219.86MPa)and elongation(4.40%),at 21.50%,14.77% and 15.48% higher than with the matrix alloy,respectively.This article has also studied heat treatment of ZL105 alloy,and discusses the evolution of aging microstructure by comparison with modified ZL105 alloy.During solution treatment,(Pr+Ce)can effectively promote Si and strengthening phases were dissolved in solid solution.So superior roundness of eutectic Si was also observed to be attained with 0.6wt.%(Pr+Ce)addition than unmodified alloy.According to the observation of different aging microstructure,the best aging time was 6h in modified ZL105 alloy.Mixed rare earth(Pr+Ce)could promote the nucleation of dispersion ?'(Al2Cu),it could effectively improve the age hardening in modified alloy.The proper heat-treated alloy with 0.6wt.%(Pr+Ce)consequently exhibited mechanical properties with hardness(97HV),tensile strength(238.62MPa)and elongation(5.23%),at 24.35%,24.18% and 50.72% higher than with the matrix alloy,respectively.From the analysis of the fracture surfaces,the mixed rare earth(Pr +Ce)can effectively promote the brittle fracture transform into ductile fracture in alloy.In addition,the intercrystalline corrosion of ZL105 alloy have also been studied.Results indicate that the situation of intercrystalline corrosion in ZL105 alloy from worst to slight is 4 h>8 h >6 h.When mixed rare earth(Pr + Ce)is added in the ZL105 alloy,the shape of Si phase is refined obviously and iron-rich phase fully dissolved in solid solution,so the density of corrosion current decreases significantly,and further improve the intercrystalline corrosion phenomena.