Investigation of flux containing GdCl3 on recycling Mg-Gd-Y-Zr scraps
(1. National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240, China;2. State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: The effects of GdCl3 in flux on the loss of Gd, microstructure, mechanical properties, and corrosion resistance of Mg-Gd-Y-Zr(GW103K) scrapswere investigated by ICP, XRD, SEM and EDS. The results show that the loss of Gd in the alloy decreases with increasing GdCl3 content in the flux, and the mechanism of GdCl3 suppressing the loss of Gd was analyzed by thermodynamic theory. The optimal average mechanical properties could be obtained when the GdCl3 content in the flux was 5% (mass fraction). Compared with the alloy only treated by JDMJ flux, the σb and σs of GW103K alloy were improved from 160.91 MPa and 133.88 MPa to 224.96 MPa and 157.91 MPa by 39.8% and 17.95%, respectively. Immersion test shows the corrosion rate of Mg-Gd-Y-Zr alloy refined by JDMJ+5.0% GdCl3 flux was decreased dramatically from 0.762 mg/(cm2.d) to 0.437 mg/(cm2.d) by 42.7%. GdCl3 has no effect on the fracture pattern of GW103K alloy.
Key words: magnesium alloy; gadolinium; mechanical properties; refining, thermodynamics