نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Grain size, as a key structural parameter, plays a significant role in determining the mechanical and physical behavior of materials. In this regard, this research dealt with the effect of surface mechanical attrition treatment on the mechanical and corrosion behavior of 7075 aluminum alloy, which was investigated by varying the shot peening duration and shot size. The results showed that this process, in addition to refining the grain size from about 15 μm to less than 3 μm, significantly increased the hardness of the samples by up to 50%. Increasing the shot peening duration and decreasing the shot size led to further improvements in hardness, with the sample treated with 3 mm shots for 10 minutes (sample 3-10) exhibiting the highest hardness (72 Vickers). Moreover, surface mechanical attrition treatment reduced the corrosion rate of the samples compared to the as-received condition, with sample 3-10 showing the lowest corrosion rate. Electrochemical impedance spectroscopy results were consistent with polarization tests, confirming the enhancement of impedance and corrosion resistance in the processed samples. The Warburg parameter was identified as an indicator for evaluating the quality of the protective layer and ion diffusion. Additionally, grain refinement and increased grain boundary area, despite increased surface roughness, contributed to improved corrosion resistance. Also, the surface mechanical attrition treatment formed a harder outer layer that became thicker with longer peening durations and smaller shot sizes. Uniform distribution of intermetallic phases and grain refinement transformed the corrosion mode from localized to uniform. These changes were evident in X-ray diffraction patterns as decreased peak intensity and increased peak broadening.
کلیدواژهها English
