Corrosion behavior of mechanically alloyed A6005 aluminum alloy composite reinforced with TiB2 nanoparticles
Fecha
2020
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Editor
Wiley-V C H Verlag Gmbh
Resumen
Corrosion susceptibility of the A6005 alloy reinforced with n‐TiB2 was studied
through electrochemical tests. The mechanical alloying (MA) technique was
used as the processing route and a posterior hot extrusion was employed to
consolidate the powders. Bulk samples were characterized by X‐ray diffraction,
scanning electron microscopy, transmission electron microscopy, and microhardness
tests. The combination of both MA processing and 5 wt% n‐TiB2
addition in the aluminum matrix produced 61% increase of microhardness.
Electrochemical tests were performed in 3.5 wt% NaCl solution to assess the
effect of MA processing and TiB2 presence on corrosion behavior. The corrosion
resistance of the samples processed by MA increased slightly compared with the
base A6005 alloy. The amorphous Al2O3 phase formed during MA processing
was the cause of this increase, providing continuity to the passive layer.
Furthermore, the addition of TiB2 on the sample processed by MA did not
significantly affect corrosion resistance. Polarization tests confirmed that the
reinforced sample had similar icorr to that of the unreinforced alloy, and cyclic
polarization tests revealed that pit nucleation sites were localized in the
interface between Al2O3 and the aluminum matrix.