Effect of temperature on tensile properties of a third-generation low- cost single crystal superalloy: Experiments and molecular dynamics simulations

F Leng and LR Liu and PS Lv and J Zhang and YS Zhao, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 927, 147956 (2025).

DOI: 10.1016/j.msea.2025.147956

In this work, the tensile properties of a third-generation low-cost single crystal (SX) superalloy were tested at different temperatures. By microstructure analysis and molecular dynamics (MD) simulation, deformation mechanisms were studied. The results showed that with the rising of test temperature, the yield strength of the experimental alloy first increased and then decreased, and the maximum yield strength of the alloy was 949.8 MPa at 760 degrees C, which exhibited obvious anomalous yielding phenomenon. As test temperature increased, the fracture mode of the experimental alloy translated from pure shear fracture to micropore accumulation fracture. At room temperature (RT) and 760 degrees C, the deformation mechanism of the alloy mainly was dislocations slipping in the gamma matrix and partial dislocations cutting into the gamma ' phase to form stacking faults (SFs). At 760 degrees C, the formation of Lomer-Cottrell (L-C) locks led to the exceptionally excellent tensile strength of the experimental alloy. At 980 degrees C and 1100 degrees C, deformation mechanism of the alloy was dislocations climbing and bypassing over gamma ' particles and forming dislocation networks at the gamma/gamma ' interfaces. In molecular dynamics (MD) simulation, the density of dislocations and typical dislocation structures of experimental alloy were analyzed at yield point. At 760 degrees C, the highest dislocation density and the largest number of Stair-rod dislocations were found at yield point, which provides supplementary evidence to explain the anomalous yielding phenomenon. In this work, the deformation mechanism of a third- generation low-cost SX superalloy was comprehensively analyzed by microstructure analysis and MD simulation, which provided crucial guidance for development of third-generation lowcost SX superalloys.

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