Mn is one of the most common alloying elements in commercial Al alloys

which

however

can significantly reduce the electrical conductivity of Al alloys. The Al-7 Si-1 Fe alloy containing Mn was modified by B and Y elements to reveal the influences on its electrical conductivity as well as the modification mechanism. The results indicate that B and Y elements can effectively improve the electrical conductivity of the alloys

where the coarse slate-like eutectic silicon is transformed into the fine coral-like under the condition of Y. Meanwhile

the long needle-like Fe-rich phase in the alloy is refined and the solution Si is precipitated in the form of Al

2

Si

2

Y. Element B can promote Mn adsorption onto AlB

2

to form borides. Under the compound modification of B and Y

Mn and Y elements are adsorbed by AlB

2

to generate Al

10

Mn

2

Y adsorption layer. Moreover

surplus Y element can refine the eutectic silicon and iron-rich phases

further enhancing the electrical conductivity of the Mn-containing Al-7 Si-1 Fe alloys. With the melt holding time prolonging

the thickness of the Al

10

Mn

2

Y adsorption layer is increased. Modification effect on eutectic Si is weakened due to the Y content reduction in the melt

leading to the significant decrease of conductivity consequently.