Deformation behaviour of FeGaCe alloys at elevated temperatures

Abstract: Problem. The low ductility of binary Fe-Ga alloys significantly limits their thermomechanical processing capabilities and industrial application as magnetostrictive materials. Although alloying with rare-earth metals improves performance characteristics, the influence of temperature and hot deformation conditions on the behaviour of Fe-Ga-based alloys has been insufficiently studied, which prevents the optimisation of technological regimes for manufacturing sheet products without the risk of fracture and the formation of undesirable microstructures. Aim. To determine the influence of hot deformation temperature (700, 850, and 1000 °C) on the deformation behaviour, microstructure, and crystallographic texture of Fe80Ga20 alloys with additions of 0.1 and 0.2 % Ce, and to establish the optimal hot deformation temperature. Methods. The binary Fe80Ga20 alloy and two doped (Fe80Ga20)99.9Ce0.1 and (Fe80Ga20)99.8Ce0.2 alloys were studied. Physical simulation of hot rolling was carried out using a Gleeble 3800 simulator under plane strain conditions at temperatures of 700, 850, and 1000 °C with a strain degree of 75 %. The structure and texture were studied using optical metallography and scanning electron microscopy with EBSD analysis. Results. The addition of cerium significantly improves the ductility of the alloys at temperatures of 850 and 1000 °C. At 700 °C, intense strain hardening and crack formation are observed in all alloys. At 1000 °C, intense grain growth and the formation of a heterogeneous structure occur. The differences in the behaviour of the alloys with 0.1 and 0.2 % of Ce are insignificant. Conclusions. Cerium alloying significantly improves the ductility of the binary Fe80Ga20 alloy. The optimal hot deformation temperature for Fe-Ga-Ce alloys is 850 °C.