Gradient Microstructure Induced by Surface Mechanical Attrition Treatment (SMAT) in Magnesium Studied Using Positron Annihilation Spectroscopy and Complementary Methods

Materials

Marianna Marciszko-Wiąckowska¹  Mirosław Wróbel²  Andrzej Baczmański³  Konrad Skowron⁴  Ewa Dryzek⁴  Paweł Nowak⁵  Benoit Panicaud⁶  LéaLe Joncour⁶  Manuel François⁶ 

[1] Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Kraków, Poland;Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Kraków, Poland;Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Kraków, Poland;Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków, Poland;Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, PL-30239 Kraków, Poland;Université de Technologie de Troyes (UTT), LASMIS, 12 Rue Marie Curie, 10010 Troyes, France;

关键词: magnesium;    surface mechanical attrition treatment;    SMAT;    gradient structured materials;    positron annihilation spectroscopy;    corrosion;   

DOI  :  10.3390/ma13184002

来源: DOAJ

【 摘 要 】

Surface mechanical attrition treatment (SMAT) was used to generate a gradient microstructure in commercial grade magnesium. Positron annihilation lifetime spectroscopy and variable energy positron beam measurements, as well as microhardness tests, electron backscatter diffraction, X-ray diffraction, and electrochemical corrosion tests, were used to investigate the created subsurface microstructure and its properties. It was found that SMAT causes an increase in dislocation density and grain refinement which results in increased hardness of the subsurface zone. The mean positron lifetime values indicate trapping of positrons in vacancies associated with dislocations and dislocation jogs. The increase of the SMAT duration and the vibration amplitude influences the depth profile of the mean positron lifetime, which reflects the defect concentration profile. Electrochemical measurements revealed that the structure induced by SMAT increases the susceptibility of magnesium to anodic oxidation, leading to the enhanced formation of hydroxide coverage at the surface and, as a consequence, to the decrease in corrosion current. No significant effect of the treatment on the residual stress was found.

【 授权许可】

Unknown