Ultrasonic Rheocasting for Refinement of Mg Alloys Reinforced with LPSO Phase

Abstract:

In this work, ultrasonic rheocasting was used to refine the microstructures of Mg alloys reinforced with long period stacking ordered (LPSO) phase. The semisolid slurries of Mg-Zn-Y and Mg-Ni-Y alloys were prepared by ultrasonic vibration (UV) and then formed by rheo-squeeze casting under high squeeze pressure (~ 400 MPa). The effects of UV and squeeze pressure on microstructure and mechanical properties of the Mg alloys were studied. The results reveal that UV and rheo-squeeze casting can significantly refine the LPSO structure and alpha-Mg matrix in Mg alloys, but they cannot change the phase compositions of the alloys or the type of LPSO phase. When the squeeze pressure is 400 MPa, the average thickness of LPSO phase is decreased, and the block LPSO structure is completed eliminated and uniformly distributed at the grain boundaries. Compared with the gravity cast alloys without UV, mechanical properties of the rheocast Mg alloys were enhanced and reached the maximums when the squeeze pressure was 400 MPa.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 1607-1612
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.1607
• Online since: December 2018
• Authors: Shu Lin Lü*, Xiong Yang, Liang Yan Hao, Shu Sen Wu
• Keywords: LPSO Phase, Magnesium Alloy, Mechanical Properties, Rheocasting, Ultrasonic Vibration

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