Papers by Author: Peng Li

Abstract: Al ion implantation of AZ31 magnesium alloy is carried out with an ion implantation dose of 1×10¹⁷ ions/cm² at room temperature and at elevated temperature of about 200°C. ß-Mg₁₇Al₁₂ precipitate is observed on the ion implanted sample at elevated temperature by X-ray diffraction (XRD). Potentiodynamic polarization curves indicated that the corrosion potential and pitting corrosion breakdown potential for the samples implanted at elevated temperature are 330 and 480 mV higher than those of the unimplanted sample, respectively. The ß-phase precipitate is beneficial to the improvement in corrosion resistance of magnesium alloy. In addition, Al enrichment on the implanted surface also contributes to the improved corrosion resistance.

Abstract: Abstract. HIPIB irradiation of magnesium alloy is carried out at a specific ion current density of 100 A/cm2 with shot number from one to ten in order to explore the effect of shot number on crater formation of magnesium alloy. Surface morphologies, surface roughness and mean spacing of surface profile irregularities of the irradiated samples are examined by scanning electron microscopy (SEM) and profilometer technique, respectively. It is found that the surface roughness, the mean spacing of surface profile irregularities, and the maximum crater diameter on the irradiated surface increase with increasing shot number, whereas the crater density decreases as the shot number increases.

Abstract: HIPIB irradiation into AZ31 magnesium alloy is performed at ion current density of 100-300 A/cm² with 1 shot. The surface morphologies and surface profiles of the irradiated AZ31 magnesium alloy samples are characterized by scanning electron microscopy (SEM) and profilometer, respectively. It is found that HIPIB irradiation leads to the formation of crater in local region of irradiated samples, and crater density increases with increasing ion current density. Both the surface roughness that reflects the vertical wave of surface profile and the mean spacing of surface profile irregularities that reflects the horizontal wave of surface profile increase as ion current density increases. These results are in agreement with the SEM observation on the irradiated surface.

Abstract: HIPIB irradiation experiment is carried out at lower energy density of 0.55 J/cm2 with shot number from 1 to 10, and dry sliding wear behavior is investigated in order to explore the low energy-modification of magnesium alloy by HIPIB. It is found that HIPIB irradiation leads to the increase in surface hardness and therefore the improvement in wear resistance compared with the original sample. The improved wear resistance is mainly ascribed to the enhanced surface hardness induced by HIPIB irradiation.

Abstract: HIPIB irradiation experiment is carried out at a specific ion current density of 1.1 J/cm2 with shot number from one to ten in order to explore the effect of shot number on electrochemical corrosion behavior of magnesium alloy. Surface morphologies, microstructure and corrosion resistance of the irradiated samples are examined by scanning electron microscopy (SEM), transmission electron microscope (TEM) and potentiodynamic polarization technique, respectively. It is found that HIPIB irradiation leads to the increase in open circuit potential, corrosion potential and breakdown potential, and the decrease in the corrosion current density and the corrosion rate as compared to the original sample. The improved corrosion resistance is mainly attributed to the grain refinement and surface purification induced by HIPIB irradiation.