Degradation mechanism of rare earth modified Al-Mg-Zn matrix composite reinforced with ceramics particles

摘要

Rare earth modified Al -Mg-Zn matrix composites reinforced with TiC and Al2O3 ceramic particles are successfully prepared via in situ reaction of Al:TiO2:C:RE2O3 system during self-propagating high-temperature synthesis. The in situ reaction mechanism, preparing parameters, microstructure evolution and corrosion behavior are studied by X -ray diffraction, scanning electron microscopy, optical microscopy and various corrosion tests. The results showed that the added rare earth oxides could minimize the dimension of in situ particles and refine the grain size of Al-Mg-Zn matrix composites with an average size of 50 μm. Moreover, the rare earth oxides could promote the dispersion distribution of in situ particles. Based on the above-mentioned results, the corrosion behavior of Al-Mg-Zn matrix composites reinforced with TiC and Al 2O3 ceramic particles is investigated b y microstructure characterization, electrochemical experiments and density function theory calculation. The results indicated that the addition of TiC and Al2O3 particles reduces the corrosion resistance of the composite material. Further, the corrosion me chanism of rare earth modified Al-Mg-Zn matrix composites reinforced with TiC and Al 2O3 ceramic particles is discussed.