Strengthening Effect of Y2O3 on AZ92 Magnesium Alloy Using Stir Casting Process

• Published in: International journal of metalcasting 2021-07, Vol.15 (3), p.818-828
• Main Authors: Moussa, M. E., El-Hadad, S., Khalifa, W.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Metallic Materials; Structural Materials
• ISSN: 1939-5981; 2163-3193
• DOI: 10.1007/s40962-020-00509-z

Strengthening effect of Y 2 O 3 on AZ92 magnesium alloy using stir casting process has been investigated. Nominal amounts of Y 2 O 3 (0, 1, 1.5, 2, 2.5 and 3 in wt%) were added into the melt vortex in the form of preformed master powder (Mg–30 wt% Y 2 O 3 ) to improve their wettability with molten AZ92 alloy. The results showed clearly that without Y 2 O 3 addition, the microstructure of the investigated alloy is composed of α-Mg which appeared as coarse dendritic structure, divorced eutectic-containing massive β-Mg 17 Al 12 phase and super-saturated α-Mg solid solution. With Y 2 O 3 addition, the distribution of Y 2 O 3 particles was found within the inter-dendritic regions of the primary α-Mg phase. At 2.5 wt% Y 2 O 3 , a near uniform distribution of Y 2 O 3 particles along the grain boundaries of AZ92 alloy matrix was successfully obtained. However, further addition resulted in agglomeration of Y 2 O 3 particles at 3 wt% addition level. The average tensile strength of the investigated AZ92 alloy was increased from 169 MPa to 198 MPa without a significant reduction in its ductility at optimum addition of 2.5 wt% Y 2 O 3 . The fracture mechanism has been also investigated.