Effect of CeO_2 on heat transfer and crystallization behavior of rare earth alloy steel mold fluxes

To improve the heat transfer capability and the crystallization property of the traditional mold flux, CaF_2 was replaced with B_2O_3. Then, the influences of CeO_2 on the heat transfer and the crystallization of the CaF_2-bearing mold flux and the new mold flux with 10 wt% B_2O_3 were studied using a slag film heat flux simulator and X-ray diffraction(XRD). The results revealed that the addition of CeO2 reduced the heat transfer by increasing the solid slag thickness and the crystallization of two mold fluxes. However, CeO_2 had less effect on the B_2O_3-containing mold flux compared with the CaF_2-bearing mold flux. According to the analyses, the CeO_2 contents in the CaF_2-bearing mold flux and the B_2O_3-containing mold flux should not exceed 8 wt% and 12 wt%, respectively. Therefore, these experimental results are beneficial to improve and develop the mold flux for casting rare earth alloy steels.

Design and fabrication of lightweight AlCrFeNiTi_(x) compositionally complex alloys with exceptional specific strength

This study focuses on compositionally complex alloys(CCAs),aiming to achieve a balance between high strength and low density for new energy and aerospace applications.The composition of AlCrFeNiTi_(x) CCAs is strategically guided by employing density functional theory and the theoretical design of thermodynamic calculations.Bulk CCAs,particularly AlCrFeNiTi_(0.25) alloy,demonstrate remarkable specific yield strength(1640.8 MPa) and 22.7% maximum strain.The incorporation of Ti facilitates the formation of lightweight and high-strength L2_(1)phase,contributing to the overall high specific strength.Synergistic effects of grain boundary strengthening,solid solution strengthening,Orowan strengthening and Peierls flow stress further enhance strength.Detailed exploration of micros tructural changes during fracture reveals the role of ordered phases in suppressing crack propagation and absorbing energy within disordered phases,thereby improving the toughness and fracture resistance of CCAs.These methods and discoveries establish a robust foundation for advancing the development of novel lightweight CCAs.