This experimental work is aimed at studying the effect of microstructural modifications induced by post-processing heat treatments on the corrosion behavior of silicon-aluminum alloys produced by means of laser powder bed fusion (LPBF). The manufacturing technique leads to microstructures characterized by the presence of melt pools, which are quite different compared to casting alloys. In this study, the behavior of an AlSi10Mg alloy was evaluated by means of intergranular corrosion tests according to ISO 11846 standard on heat-treated samples ranging from 200 to 500 °C as well as on untreated samples. We found that temperatures above 200 °C reduced microhardness of the alloy, and different corrosion morphologies occurred due to the modification of both size and distribution of silicon precipitates. Selective penetrating attacks occurred at melt pool borders. The intergranular corrosion phenomena were less intense for as-produced specimens without heat treatments compared to the heat-treated specimens at 200 and 300 °C. General corrosion morphologies were noticed for specimens heat treated at temperatures exceeding 400 °C.

The paper assesses the durability of one-part alkali-activated slag-based mortars (AAS) in different aggressive environments, such as calcium chloride- and magnesium sulphate-rich solutions, in comparison with traditional cementitious mortars at equal water to binder ratio. Moreover, the freezing and thawing resistance was evaluated on mortars manufactured with and without air entraining admixture (AEA). Experimental results indicate that the alkali content is a key parameter for durability of AAS: the higher the alkali content, the higher the resistance in severe conditions. In particular, high-alkali content AAS mortars are characterized by freeze–thaw resistances similar to that of blast furnace cement-based mixtures, but lower than that of Portland cement-mortars while AAS with low activators dosages evidence a very limited resistance in cold environment. The effectiveness of AEA in enhancement of freeze–thaw resistance is confirmed also for AAS mortars. Moreover, AAS mixtures are quasi-immune to expansive calcium oxychloride formation in presence of CaCl₂-based deicing salts, but they are very vulnerable to magnesium sulphate attack due to decalcification of C-S-H gel and gypsum formation.