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Abstract In this work, effects of pre-oxidation treatment on the corrosion behavior of nanoparticles reinforced FeCrB alloy (JDF) in liquid aluminum have been investigated experimentally and theoretically. Results reveal that the oxidized JDF exhibits an excellent anti-corrosion performance, which is 2, 8, and 21 times higher than that of JDF, DIN1.2888, and H13 steel, respectively. Continuous and compact oxide scales formed on the pre-oxidized JDF surface isolate the contact between the liquid aluminum and the matrix initially. As the corrosion proceeds, they can also effectively suppress the diffusion of Al atoms into the matrix and their subsequent reactions until their failure.

In this work, FeCrB-based composites modified by in-situ ceramic particles (TiB2 and TiC) were synthesized, and the effects of ceramic particles on their microstructure evolution and the corrosion-resistant behavior in liquid aluminum were systematically investigated. Results indicate that the introduction of in-situ ceramic particles can significantly improve the size, morphology and distribution of borides, thus leading to a remarkable enhancement of the corrosion resistance. Based on the growth-dissolution kinetic relationship of intermetallic compounds (IMCs) at the corrosion interface, a theoretical numerical model was established to quantitatively describe the corrosion behavior of ferrous alloys in liquid aluminum, and the multi-scale corrosion-resistance mechanism is proposed to elucidate the excellent performance of FeCrB-based composites in liquid aluminum.

Effect of in-situ nanoparticles (NPs) induced by Ti addition on the microstructure and tribological properties of FeCrB alloys has been investigated systematically by various advanced techniques. The results reveal that the TiC and TiB2 nanoparticles can be in-situ formed when adding Ti into the FeCrB alloys and they show great contribution to the microstructure refinement and tribological performance improvement of FerCrB alloys. With the gradual addition of Ti, the improvement effect of in-situ NPs increases initially and subsequently decreases. The JDF2 alloy (refers to FeCrB alloy containing 1.17 wt % Ti) shows the finest microstructure and the exceptional wear resistance. The average size and fracture toughness of primary borides are only 11.8 % of that in FeCrB matrix alloy (without Ti addition) and increase to 22.7 MPa∙m1/2, respectively. Moreover, the wear rate measures at 3.38 × 10−5 mm3/N·m, which is only 48.8% compared to that of FeCrB matrix alloy. The underlying wear mechanisms of FeCrB alloys have been discussed by unraveling the role of in-situ nanoparticles in the microstructure evolution, which belongs to adhesive wear and abrasive wear.

Hot compression tests of a novel dual-phase Mg–Li alloy were performed in temperature range of 200–400 °C and strain rate range of 0.01–10s−1. 2D and 3D processing maps were established using Prasad's and Murty's instability criteria (methods) based on the dynamic materials model. It was found that one instability region obtained based on Prasad's instability criterion exist in the domain of power dissipation efficiency at a strain of 0.7. Prasad's and Murty's instability criteria are difficult to accurately characterize the instability characteristics of the alloy. The accuracy processing map rectified was obtained by means of Murty's and Prasad's instability criteria and microstructural analysis. On the basis of the processing map rectified, the optimum hot working parameters were obtained to be the temperature range of 320–400 °C and strain rate range of 0.01–0.4s−1 with the peak power dissipation efficiency. In this domain, the α phase undergone dynamic recrystallization (DRX) and dynamic recovery (DRV). The β-phase occurred DRX during the hot deformation. The instability regions lie in the temperature range of 200–250 °C with strain rate range of 0.01–1s−1 and the temperature range of 200–312 °C with strain rate range of 1–10s−1. Microstructural observations indicate that characteristics of the flow instabilities were flow localization, deformation twinning, the adiabatic shear bands and macro/micro cracking. The rectified processing map was successfully verified by the hot rolling test. The rectified processing map could accurately characterize workability characteristics of a novel dual-phase Mg–Li alloy and could be used for the optimization of hot working process parameters.