Doctor of Philosophy in Mechanical Engineering
Brendan O’Toole, Committee Chair
Ajit K. Roy, Committee Co-Chair
First Committee Member
Second Committee Member
Anthony E. Hechanova
Third Committee Member
Graduate Faculty Representative
Edward S. Neumann
Number of Pages
Nickel base Alloy 617 has been identified to be a suitable structural material for heat exchanger applications in both hydrogen and electricity generation using nuclear heat. A maximum operating temperature of 950°C has been specified by department of energy (DOE) for both applications to achieve a maximum possible efficiency. Therefore, an extensive investigation has been pursued to evaluate time-dependent-deformation (Creep) of this alloy as functions of temperature and applied load. The results indicate that this alloy exhibited severe creep deformation, characterized by development of an instantaneous tertiary creep region at 850 and 950°C under applied stresses corresponding to its 35% yield strength (YS) values at these temperatures. However, this alloy satisfied the deformation acceptance criteria at 5, 10, 25 and 35 percent of its YS values when loaded at 750°C. The results of crack growth studies indicate that this alloy showed an enhanced cracking susceptibility when tested within a temperature range of 100 to 200°C at the lowest loading ratio of 0.1. The fracture toughness of this alloy in terms of J IC was not significantly influenced by variation in temperature. The results of stress-corrosion-cracking study suggest that the rate of crack growth was gradually reduced with longer testing duration due to a relaxation of load with time. Microscopic evaluations of tested specimens were performed using numerous conventional techniques.
Austenitic Nickel-based Alloy 617; Crack growth; Creep deformation; Fracture toughness; Heat exchanger applications; High temperature applications; Hydrogen generation; Microstructural characteristics; Nickel alloys; Nickel-base superalloys; Nuclear energy
Materials Science and Engineering | Mechanical Engineering | Metallurgy
Hasan, Muhammad Hasibul, "Effects of mechanical and metallurgical variables on creep, fracture toughness and crack growth behavior of Alloy 617" (2009). UNLV Theses, Dissertations, Professional Papers, and Capstones. 129.