In order to improve the service life of nickel-based single crystal blades and solve the key technology of aeroengine turbine and gas turbine, domestic and overseas researchers carried out a large number of research on the failure and damage mechanism of nickel-based single crystal superalloys under service conditions in recent years. The research achievements and progress of fatigue, creep and thermomechanical fatigue damage mechanism of nickel-based single crystal superalloys under service conditions were concluded. In addition, in view of the time and cost increase caused by a large number of experiments, the research works and achievements in life prediction methods of nickel-based single crystal superalloys in recent years were summarized, and the difficulties and challenges in life evaluation and failure analysis of nickel-based single crystal superalloys were proposed.

The process of room temperature rolling is a straightforward and efficient method for producing high strength Mg-Li alloys, but the underlying strengthening mechanism remains unclear. In this study, we successfully enhanced the tensile properties of a novel dual-phase Mg-Li alloy through room temperature rolling, with a remarkable yield strength of 201 MPa and an elongation-to-failure of 14%. Microhardness testing was conducted to evaluate the contribution of the Mg- and Li- phases to the improvement in strength. The results demonstrate that the hardness of Mg-phase reaches 60 HV, which is significantly higher than the 49 HV observed in Li-phase, indicating that the Mg-phase after rolling plays a pivotal role in enhancing material strength. The presence of a high density of dislocations stored in the Mg-phase emerges as the dominant factor contributing to improved strength in Mg-Li alloys. In-situ compression testing reveals that 〈c + a〉 slip activation and twinning-induced slip serve as internal mechanisms for continuous deformation and hardening within the Mg-phase. Despite numerous precipitated Mg-phase particles within the Li-phase matrix, the hardness analysis reveals minimal strain-induced phase transformation effects on the overall strength of the Al-free and Zn-free Mg-Li alloy. These findings provide valuable insights for designing and fabricating high-strength dual-phase Mg-Li alloys.

It has been a common method to improve the mechanical properties of metals by manipulating their microstructures via static recrystallization, i.e., through heat treatment. Therefore, the knowledge of recrystallization and grain growth is critical to the success of the technique. In the present work, by using in-situ high temperature EBSD, the mechanisms that control recrystallization and grain growth of an extruded pure Mg were studied. The experimental results revealed that the grains of priority for dynamic recrystallization exhibit fading competitiveness under static recrystallization. It is also found that grain boundary movement or grain growth is likely to show an inverse energy gradient effect, i.e., low energy grains tend to swallow or grow into high energy grains, and grain boundaries of close to 30° exhibit superior growth advantage to others. Another finding is that {10–12} tensile twin boundaries are sites of hardly observed for recrystallization, and are finally swallowed by adjacent recrystallized grains. The above findings may give comprehensive insights of static recrystallization and grain growth of Mg, and may guide the design of advanced materials processing in microstructural engineering.