Surface microstructure modifications and in-vitro corrosion resistance improvement of a WE43 Mg alloy treated by pulsed electron beams. (March 2020)

• Record Type: Journal Article
• Authors: Zhang, Xu; Zhang, Kemin; Zou, Jianxin; Yan, Ping; Song, Luxia; Liu, Yingrui
• Is Part Of: Vacuum. Volume 173(2020)
• Publication Date: 2020-03
• Subjects: High current pulsed electron beam (HCPEB) -- WE43 Mg alloys -- Surface modifications -- Precipitates -- Corrosion resistance; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2019.109132
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: In the present study, the surface microstructures and in-vitro corrosion resistance of an as-cast WE43 Mg alloy after high current pulsed electron beam (HCPEB) treatments are investigated. It is shown that the surface presents craters and wavy morphology after HCPEB treatments, which are the typical characteristics of the morphology after rapid melting and cooling. The initially existed Mg14 Nd2 (Y, Gd) particles are dissolved, and the fine β՛ (c-bco, a = 0.64 nm, b = 2.223 nm and c = 0.521 nm) precipitates are formed and homogeneously dispersed in the treated layer. The electrochemical measurements in the simulated body fluid (SBF) show that the corrosion current density ( I corr ) of the 15 pulsed sample (2.66 × 10 −5 A cm −2 ) is reduced by an order of magnitude compared to that of the untreated sample (1.91 × 10 −4 A cm −2 ), and the polarization resistance ( R p ) is increased by 176.9%. The disappearance of second phase, the formation of homogeneous dispersed β՛ nano-precipitates and the chemically homogenized melted layer account for the improved corrosion resistance of the 15 pulsed WE43 sample in SBF. Highlights: Effects of HCPEB treatments on the surface and corrosion resistance of a WE43 alloy were studied. The primary Mg14 Nd2 (Y, Gd) phase were dissolved gradually in the top surface remelted layer with increasing number of pulses. The surface layer of the treated sample mainly exist a lot of fine precipitates β՛. The 15 pulsed samples exhibits the best in-vitro corrosion resistance.