Articles written in Bulletin of Materials Science
Volume 42 Issue 5 October 2019 Article ID 0204
The inﬂuence of friction stir processing parameters and the subsequent evolution of microstructures and cor-rosion behaviour of Al–SiC surface composites fabricated in the presence of graphitic ﬂakes are presented in this paper. The circumferential shear stress exerted by the rotating tool exfoliates the graphite ﬂakes into few-layered graphene during processing. These graphene ﬂakes preferentially occupy both the grain boundaries and the SiC–Al interface during recrys-tallization. The potentiodynamic polarization test, in 3.5 wt% sodium chloride (NaCl) solution, is conducted for samples processed at various tool rotational speeds and it is found that the presence of this thin graphitic layer at these locations reduces the intergranular and interfacial corrosion to a great extent. The tool rotational speed has a signiﬁcant inﬂuence on processing, and samples fabricated at an optimum tool rotational speed of 2200 rpm shows better corrosion resistance and mechanical properties as compared to that at lower and higher speeds. Raman spectroscopic analysis, X-ray diffraction studies and microhardness tests corroborate the experimental results and the proposed mechanisms.
Volume 42 | Issue 6
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