Dynamic recrystallization behavior and strengthening mechanism of a novel Mo–Ti 3 AlC 2 alloy at ultrahigh temperature

Abstract Increasing the recrystallization temperature to achieve better high‐temperature performance is critical in the development of molybdenum alloys for ultrahigh‐temperature applications, such as the newest generation of multitype high‐temperature nuclear reactors. In this study, an innovative strategy was proposed to improve the performance of molybdenum alloys at high temperature by using the two‐dimensional MAX (where M is an early transition metal, A is an A‐group element and X is C or N) ceramic material Ti 3 AlC 2 . The relationships between flow stress, strain rate and temperature were studied. The microstructure, distribution of misorientation and evolution of dislocations in the Mo–Ti 3 AlC 2 alloy were analyzed. The microscopic mechanism of the Ti 3 AlC 2 phase in the molybdenum alloy at high temperatures was clarified. The experimental results showed that the peak flow stress of Mo–Ti 3 AlC 2 at 1600 °C reached 155 MPa, which was 161.8% greater than that of pure Mo. The activation energy of thermal deformation of Mo–Ti 3 AlC 2 was as large as 537 kJ·mol −1 , which was 17.6% more than that of pure Mo. The recrystallization temperature reached 1600 °C or even higher. The topological reaction of the Ti 3 AlC 2 phase consumed a large amount of energy at high temperatures, resulting in increases in the deformation activation energy. Nanolayer structures of AlTi 3 and Ti–O Magnéli‐phase oxides (Ti n O 2 n ‐1 ) were formed in‐situ, which relied on kink bands and interlayer slip, resulting in many dislocations during deformation. Therefore, the special two‐dimensional of the structure Ti 3 AlC 2 ceramic inhibited the recrystallization behavior of the Mo alloy. The results of this study can provide theoretical guidance for the development of a new generation of molybdenum alloys for use in ultrahigh‐temperature environments.