Sharif Digital Repository

MP35N superalloy is a Co-Ni based superalloy with significant work hardening and strengthening properties. In this study secondary hardening in this alloy is investigated by different transmission electron microscopy techniqes. Images of the transmission electron microscope revealed a high density of dislocations and deformation twins in the cold work samples. There were no evidence of any Co3Mo precipitation or hcp martensitic phase in the cold worked samples. Performed study on aged sample showed wide distribution of stacking fault by traditional techniqes and Weak Beam. On the other hand, information which was concluded of STEM method with HAADF detector, exhibits the entrance of heavy... 

Many Investigations have been carried out on high work hardening, strengthening and secondary hardening of MP35N superalloy. In this study, behavior of MP35N under uniaxial hot compression at 600 °C with true strain of 0.05, 0.10, 0.16 and 0.22 was investigated. After calculating on stress- true strain curve, work hardening rate versus strain come out. Serrated flow has been seen in all mentioned strains. In TEM investigation on these samples, dislocations array with extended faults and micro twinning have been seen. According to Suzuki mechanism with solute partitioning and diffusion of solute, stacking fault extended. Uninterrupted separations and combinations of partial dislocations lead... 

This study aims to investigate the creep deformation mechanisms in nickel-based single-crystal superalloys for which two-dimensional molecular dynamics (MD) simulations are conducted to model various temperature, stress conditions and phase interface crystal orientations. Ni-based single-crystal superalloys are of great importance in the aircraft industry, on account of their excellent high temperature creep resistance. This characteristic mainly originates from two features considered in their structure: first, their two-phased microstructure comprising gamma ( ) and gamma prime ( ), and the nature of this superalloy itself which is single-crystal. MD is a powerful tool to gain insight into...