Surface microstructure and property modifications in a Mg-8Gd-3Y-0.5Zr magnesium alloy treated by high current pulsed electron beam

• Published in: Journal of alloys and compounds Vol. 788; pp. 231 - 239
• Main Authors: Zhang, T.C., Zhang, K.M., Zou, J.X., Yan, P., Yang, H.Y., Song, L.X., Zhang, X.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05-06-2019; Elsevier BV
• Subjects: Compressive properties; Corrosion; Corrosion rate; Corrosion resistance; Electron beams; Gadolinium; Hardness; High current; High current pulsed electron beam (HCPEB); Magnesium base alloys; Mg-RE alloys; Microhardness; Microstructure; Precipitates; Residual stress; Solid solutions; Surface layers; Surface treatment; Thermal stress; Mg-RE alloys; High current pulsed electron beam (HCPEB); Corrosion; Hardness; Surface treatment
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.02.130

In the present study, the effect of high current pulsed electron beam (HCPEB) surface treatments on the microstructure, composition, stress states and properties of a Mg-8Gd-3Y-0.5Zr alloy has been investigated. The surface layers showed different features in microstructure and residual stress states under different number of pulses. Such a variation is essentially due to the different level of the dissolution of β-Mg5(Gd,Y) particles in remelted layers and the impact from thermal stresses generated by HCPEB treatments. The results have shown that, after 5 pulses of HCPEB treatment, maximum hardness in the surface layer of the sample was increased by 35% and the corrosion rate in 3.5 wt% NaCl water solution was reduced by 30% as compared with those of the untreated sample. The formation of nano structured cells of Mg-RE solid solution and β-Mg5(Gd,Y) nano precipitates, together with the residual compressive stress in the surface layer of the 5 pulsed sample account for the increased microhardness and improved corrosion resistance of the HCPEB treated Mg-8Gd-3Y-0.5Zr Mg alloy.
•Mg5(Gd,Y) precipitates in the Mg-8Gd-3Y-0.5Zr alloy were dissolved into matrix after HCPEB treatment.•Hardness is increased in the HCPEB treated surface layers due to the formation of nanostructures and residual stresses.•Increased Gd/Y content and residual compressive stress in the 5 pulsed sample account for the improved corrosion resistance.