Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is near...Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is nearly completely dissolved and as a result, a super-saturated solid solution forms on the re-melted surface. The microhardness is increased both in and far beyond the heat-affected zone (HAZ), reaching about 250um. Measurements on sliding wear have shown that the wear resistance of the treated samples was improved by a factor of about 2.4 as compared to the as-received sample. It is also found that the sliding wear resistance can be further improved by surface alloying with TiN.展开更多
Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl sol...Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution, showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.展开更多
In a basic solution containing 18 g/L Na2SiO3,the anodizing of AZ91HP magnesium alloy was investigated with and without addition of phytic acid(C6H18O24P6). The thickness,composition and morphologies of anodic coating...In a basic solution containing 18 g/L Na2SiO3,the anodizing of AZ91HP magnesium alloy was investigated with and without addition of phytic acid(C6H18O24P6). The thickness,composition and morphologies of anodic coatings formed at different concentrations of C6H18O24P6 were determined. The corrosion resistance of anodized samples was evaluated by salt spray test in 5%(mass fraction) NaCl solution. The results show that C6H18O24P6,which is harmless and environmentally friendly,greatly affects the properties of anodic coatings. Under the same electric parameters,the final voltage increases with the concentrations of C6H18O24P6. The coating thickness slightly increases from 8 μm formed in the base electrolyte without C6H18O24P6 to 9-10 μm in C6H18O24P6 solution. The P content and color of anodic coatings separately increases and darkens with the addition of C6H18O24P6. After the anodizing solutions were changed from 0 to 16 g/L addition of C6H18O24P6,the largest size of micropores decreases from 4 μm to 3 μm,while the number of micropores per area on coating surface decreases from 0.076 to 0.047 μm-2. The salt spray test shows that C6H18O24P6 can improve the corrosion resistance of the anodic coatings and the coating formed in the electrolyte containing 12 g/L C6H18O24P6 exhibits the highest corrosion resistance.展开更多
文摘Surface modification of magnesium alloy AZ91HP (9wt%Al, 0.5wt%Zn, 0.5wt%Mn, Mg remaining percentage) by high current pulsed electron beam (HCPEB) treatment was studied in this paper. The secondary phase MgnAln is nearly completely dissolved and as a result, a super-saturated solid solution forms on the re-melted surface. The microhardness is increased both in and far beyond the heat-affected zone (HAZ), reaching about 250um. Measurements on sliding wear have shown that the wear resistance of the treated samples was improved by a factor of about 2.4 as compared to the as-received sample. It is also found that the sliding wear resistance can be further improved by surface alloying with TiN.
基金the scientific research foundation for the returned overseas Chinese scholars from state education ministry of P.R.China.
文摘Surface treatment of magnesium alloys AZ31 and AZ91HP by a high current pulsed electron beam (HCPEB) was investigated in the present paper. The corrosion resistance of treated samples was tested in a 5% (wt%) NaCl solution, showing remarkably improvement as manifested by polarization curves. According to EPMA analysis, the intermetallic Mg17Al12 in the surface layer of AZ91HP sample almost disappeared after the treatment of HCPEB, leaving the surface layer in a state of supersaturated solid solution. Both the augmentation of aluminum content and the formation of supersaturated structure in the surface layer are believed to contribute to the improved corrosion resistance of AZ31 and AZ91HP.
基金Project(0650034) supported by the Natural Science Foundation of Jiangxi Province, China
文摘In a basic solution containing 18 g/L Na2SiO3,the anodizing of AZ91HP magnesium alloy was investigated with and without addition of phytic acid(C6H18O24P6). The thickness,composition and morphologies of anodic coatings formed at different concentrations of C6H18O24P6 were determined. The corrosion resistance of anodized samples was evaluated by salt spray test in 5%(mass fraction) NaCl solution. The results show that C6H18O24P6,which is harmless and environmentally friendly,greatly affects the properties of anodic coatings. Under the same electric parameters,the final voltage increases with the concentrations of C6H18O24P6. The coating thickness slightly increases from 8 μm formed in the base electrolyte without C6H18O24P6 to 9-10 μm in C6H18O24P6 solution. The P content and color of anodic coatings separately increases and darkens with the addition of C6H18O24P6. After the anodizing solutions were changed from 0 to 16 g/L addition of C6H18O24P6,the largest size of micropores decreases from 4 μm to 3 μm,while the number of micropores per area on coating surface decreases from 0.076 to 0.047 μm-2. The salt spray test shows that C6H18O24P6 can improve the corrosion resistance of the anodic coatings and the coating formed in the electrolyte containing 12 g/L C6H18O24P6 exhibits the highest corrosion resistance.
