In order to solve the problem of poor mechanical properties

effects of Nd and Nd-Ti-B modification treatment on solidification structure and mechanical properties of Al-18Mg

2

Si alloy were investigated by OM

XRD and SEM.The results reveal that

for Al-18Mg

2

Si alloy after 0.25% Nd modification

the size of primary Mg

2

Si is decreased from 65μm to 26μm

and the number ofα-Al phase enclosing primary Mg

2

Si is increased.In addition

the lamellar space of eutectic Mg

2

Si is reduced from 3

5

μm to 1μm with the decrease of size and increases of eutectic colony number

compared with those of ones without modification.After 0.25%Nd+0.1%Ti+0.02%B compound modification

the size of primary Mg

2

Si is reduced to 15μm with great increase of content.The tensile strength of Al-18Mg

2

Si alloy after0.25%Nd and 0.25%Nd+0.1%Ti+0.02%B modification is improved by 9.6%and 23.6%

and the elongation is increased by 33% and 75%

respectively.The effect of Nd-Ti-B compound modification is superior to that of single Nd modification.