Effect of in-situ Al2O3 on tensile strength and ductility of AlSi10Mg alloy fabricated by selective laser melting

Abstract The in-situ Al2O3 modified AlSi10Mg alloy was fabricated by selective laser melting using AlSi10Mg/ZnO mixed powders. The results show that the aluminothermic reaction between the Al and ZnO occurs when the laser fuses the AlSi10Mg/ZnO mixed powders. This leads to the in-situ formation of Zn and Al2O3 nanoparticles in the AlSi10Mg alloy. The Zn can exist in the Al matrix as solid solution atoms. The effect of Zn on the tensile strength and ductility of the AlSi10Mg alloy is rather limited. However, the in-situ Al2O3 impedes the motion of dislocations and thus improves the strength of the AlSi10Mg alloy. Moreover, the dislocations accumulated around the in-situ Al2O3 are gradually annihilated along the Al/Si boundaries. Thus the ductility of the AlSi10Mg alloy is scarcely affected by the in-situ Al2O3.