Effects Of Mn And P On The Morphology And Properties Of Hypereutectic Al-Si Alloy Containing Iron-Rich

This paper takes Al-22wt.%Si as the matrix,preparation of test specimens by adding Fe,Mn and P,study on the morphology and properties of the casting,heat treatment state and 800? high temperature isothermal treatment of alloy,hoping to get the control conditions of tissue properties of this alloy is better,at the same time for the retrieval and utilization of high iron hypereutectic Al-Si alloy as the reference.The experimental results indicated that:The iron-rich phases were composed of Al8(Fe,Mn)2Si,Al9(Fe,Mn)2Si2,Al3(Fe,Mn)Si2 after adding Fe and Mn in the as-cast samples,Morphology improved along with the increase of the Mn/Fe.The iron-rich phases were composed of Al8(Fe,Mn)2Si,Al9(Fe,Mn)2Si2,Al3(Fe,Mn)Si2,Al3(Fe,Mn)Si after adding Fe,Mn and P in the as-cast samples,the addition of P changed the solidification sequence of alloy and generated a new iron-rich phase which was Al3(Fe,Mn)Si,the presence of Mn to further stabilize the new iron-rich phase.In 800? high temperature isothermal treatment,Primary silicon in the various components alloy had according to "variation of the five petal star shape ?dendritic ?dendritic decomposition fuse" transition trend,the addition of P forming heterogeneous core for Si and delaying the transition speed.There was only one iron-rich phase Al3(Fe,Mn)Si2 after by 800? high temperature isothermal treatment.Solidification temperature interval showed a trend of decreased firstly and then increased with the increase of the Mn/Fe after adding Fe,Mn or Fe,Mn and P;But when Mn/Fe=0.6,the solidification temperature interval with a minimum of 220.2 ? for only adding Fe,Mn in the samples,when Mn/Fe=1,the solidification temperature interval with a minimum of 274.1? for the other.So the addition of P can improve the solidification temperature interval of alloy.Tensile strength showed a trend of increased firstly and then decreased with the increase of the Mn/Fe after adding Fe,Mn and P;The tensile strength reached the maximum value of 148MPa when Mn/Fe=0.6.Tensile strength showed a trend of increased firstly and then decreased with the increase of the P in the Al-22wt.%Si-3wt.%Fe-1.8wt.%Mn-0.4wt.%RE-0.5wt.%Mg-xP;The tensile strength reached the maximum value of 189MPa when ?(P)=0.045wt.%.