Influence of Si Addition on the Microstructure, Hardness and Elevated-Temperature Sliding Wear Behavior of AX53 Magnesium Alloy

• Published in: International journal of metalcasting 2022-01, Vol.16 (1), p.385-398
• Main Authors: Moussa, M. E., El-Hadad, S., Nofal, A.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Metallic Materials; Structural Materials; Technical Paper
• ISSN: 1939-5981; 2163-3193
• DOI: 10.1007/s40962-021-00611-w

The influence of Si additions (0.1, 0.3, 0.6, 1 wt%) on microstructure, hardness and elevated-temperature sliding wear behavior of AX53 magnesium alloy (Mg—5 wt% Al—3wt% Ca) has been investigated by performing a ball-on-disk high-temperature wear test at different temperatures (RT, 100, 150, 200 °C). The results clearly show that without Si addition, the microstructure of the as-cast AX53 alloy consists of dendritic primary α-Mg phase and lamellar eutectic structure consists of layers of α-Mg and (Mg, Al) 2 Ca lamellar intermetallic compounds that alternate together. With Si additions, a new intermetallic compound rich in Si can be defined as MgCaSi of a granular, needle and bulky morphologies with different sizes forms within the inter-dendritic regions of α-Mg. Formation of fine granular MgCaSi intermetallic compounds as well-distributed particles is associated with the addition of 0.6 wt% Si. The alloy containing 0.6 wt% Si shows the highest hardness value and the best wear resistance at all temperatures of the wear test. In the Si-containing alloys, weight loss increases with increasing the temperature of wear test compared to the RT wear test regardless of the Si content. However, the Si-containing alloys have lower weight loss than the investigated alloy without Si addition. The wear mechanisms have been also discussed.