This study investigates the effect of micr-oaggregate filling with copper tailing on the pore structure of cement paste containing copper tailing (CPCT). The particle size of the CPCT and the pore structure of CPCT were analyzed by laser particle size analysis and mercury instruction porosimetry (MIP). Results showed that at the early stage of curing time, with increasing copper tailing content, the compressive strength of cement mortar with copper tailing (CMCT) was lower, and the porosity and pore diameter of CPCT were higher and greater; with the extension of curing age, when the content of copper tailing was less than 30%, the compressive strength of CMCT and the porosity of CPCT changed slightly with the increase of the content of copper tailing. However, the maximum hole diameter of CPCT decreased gradually (a curing age between 7 d and 365 d under standard conditions). Scanning electron microscopy analysis showed that at the early stage of cement hydration in the CPCT, the copper tailing did not fill the pores in CPCT well, while in the later stage of cement hydration, the microaggregates of copper tailing filled the pores well and closely combined with the surrounding hydration products. In the later stage of cement hydration, the microaggregate filling of copper tailing was primarily responsible for the strength increase of the CMCT.

The hierarchical microstructures of high-entropy alloys (HEAs) can result in highly complex magnetic textures and properties. Here, we use high spatial resolution correlative magnetic, structural and chemical imaging to investigate magnetic textures in phase separated AlCoxCr1 – xFeNi (x = 0.5 and 1) HEAs. The AlCoFeNi HEA, which contains nm-sized A2 precipitates in a B2 matrix, supports large magnetic domains with small-angle magnetization variations. In contrast, the AlCo(Cr)FeNi HEA, which undergoes hierarchical phase separation, contains an unexpected distribution of magnetic vortices within individual A2 precipitates in a weakly ferromagnetic B2 host, in addition to weakly ferromagnetic or nonmagnetic B2 precipitates in large magnetic domains of the A2 phase, as well as Fe-Co-rich inter-phase A2 regions that have strong magnetization. The coercivity is attributed to a complicated magnetization reversal process, which includes the successive reversal of the magnetic vortices. These results provide important insight for the rational design of HEAs with unique and tailored magnetic properties.

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