滑动摩擦加工挤压Mg-Dy-Ni合金的显微组织、力学及腐蚀性能

研究了滑动摩擦加工(SFT)Mg-12Dy-1.1Ni(wt.%)合金的显微组织、力学及腐蚀性能.结果表明:SFT细化了挤压合金表层的晶粒,碎化了LPSO相和Mg₂₄Dy₅颗粒相并促使其均匀分布.SFT同时提高了挤压合金的力学和腐蚀性能.SFT合金具有较高的最大抗拉强度(δ_UTS=356 MPa)和延伸率(ε=25%).SFT合金高的拉伸性能主要来自晶粒细化、18R-LPSO相的弥散强化和14H-LPSO相的析出强化.与挤压合金相比,SFT合金在0.1 mol NaCl溶液中浸泡1 h的失重率从3.02 mg/cm²/h降低到1.86 mg/cm²/h,腐蚀电流密度降低到2.98 mA/cm²,SFT合金良好的腐蚀性能与合金元素及第二相颗粒的均匀分布有关.

Microstructure,mechanical and corrosion properties of an as-extruded Mg-Dy-Ni alloy modified by sliding friction treatment

The effects of the sliding friction treatment (SFT) on the microstructure, mechanical and corrosion properties of as-extruded Mg-12Dy-1.1 Ni (wt.%) alloy were investigated.The results shows that the SFT refined the surface grain size of the as-extruded alloy, the LPSO phase and Mg₂₄Dy₅ granular phase were crushed, and promoting their uniformly distributed. The SFT improved the mechanical and corrosion properties of the extruded alloy. The SFT alloy exhibited the higher maximum tensile strength (UTS=356 MPa) and elongation (ε=25%). The high tensile properties of the SFT alloy mainly originated from grain refinement, the dispersion strengthening of 18R-LPSO phase andphase precipitation strengthening of 14H-LPSO. Additionally,the weight loss rate of the SFT alloy immersed in 0.1 mol NaCl for 1 h decreased from 3.02 mg/cm²/h to 1.86 mg/cm²/h compared with as-extruded alloy. The corrosion current density of the SFT alloy decreased to 2.98 mA/cm². The good corrosion property of the SFT alloy was related to the uniform distribution of alloying elements and the second phase particles.