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The microstructure and corrosion behavior of as-cast Mg-1.5Zn-0.6Zr alloy and a comparative AZ91D alloy were investigated through metallographic observations, X-ray diffraction, electron probe micro-analysis, immersion tests, and cyclic polarization measurements. The Mg-1.5Zn-0.6Zr exhibited a singlephase solid solution characteristic and had fine equiaxed grains, while the AZ91D consisted of a-Mg matrix and b-Mg 17 Al 12 second phases. It was found that Zr is enriched in the center of most grains in Mg-1.5Zn-0.6Zr. Immersion tests showed that the corrosion rate of Mg-1.5Zn-0.6Zr was only about half of that of AZ91D in 5% NaCl solution. The better corrosion properties of Mg-1.5Zn-0.6Zr we owe to the elimination of intensive galvanic corrosion reactions, the formation of much more compact and uniform corrosion films, and the stabilization of magnesium solid solution by Zr. The Mg-1.5Zn-0.6Zr showed a desired uniform corrosion behavior during degradation, which can be reasonably explained by cyclic polarization measurements. The Mg-1.5Zn-0.6Zr alloy displays good corrosion resistance and could be a promising degradable biomaterial. Materials and Corrosion 2015, 66, No. 1 Comparison of corrosion behavior of Mg-1.5Zn-0.6Zr and AZ91D

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Industry trials were carried out to study the removal efficiency of inclusions in Al-killed liquid steel in the processes of BOF-LF-RH-CC and BOF-RH-CC. It was found that the removal efficiency of inclusions has a high dependence on inclusion types. Solid inclusions are more easily to be removed than liquid inclusions. The removal efficiency of solid Al 2 O 3 inclusions is higher than that of solid CaO-Al 2 O 3 -MgO inclusions. As liquid CaO-Al 2 O 3 -MgO inclusions coexisted with solid CaO-Al 2 O 3 -MgO inclusions in the liquid steel, the low removal efficiency of inclusions in RH degassing process was found in BOF-LF-RH-CC process. However, high removal efficiency and ultra-low total oxygen (T.O) content were obtained in BOF-RH-CC process because the inclusions were mainly composed of solid Al 2 O 3 although initial T.O content before RH degassing was relatively high. This is due to the fact that solid Al 2 O 3 tends to form clustershaped inclusions which have both a higher contact angle and a lower work of adhesion with steel than calcium aluminate, resulting in easier removal by RH degassing. Therefore, it is proposed to weaken steel-slag reaction and calcium treatment before RH degassing to retain solid Al 2 O 3 inclusions in the steel.