Date of Graduation
Statler College of Engineering and Mineral Resources
Mechanical and Aerospace Engineering
Bruce S. Kang.
Comparative fracture tests of two Fe-28%Al iron aluminides revealed that alloys with B, Zr, and C addition (FA189) are extrinsically more susceptible to environmental embrittlement than the base ternary alloy (FA186) under constant tensile loading condition. This may due to the effect of smaller grain sizes caused by alloy addition. To further investigate the grain boundary size effect as related to the susceptibility of hydrogen embrittlement, comparative finite element modeling simulations of intergranular fracture of two iron aluminides (FA186 and FA189) were carried out. The computational simulations involved sequentially coupled stress and hydrogen diffusion analyses to determine crack-tip stress state and the extent of hydrogen diffusion at the crack tip region. Principal strain failure criteria is adopted to simulate intergranular fracture. Good qualitative agreement between the modeling and experimental results is observed. The results further confirm our assessment that grain boundary morphology is important in controlling environmental embrittlement of iron aluminides.
Cisloiu, Roxana, "Computational modeling of hydrogen embrittlement of iron aluminides" (2001). Graduate Theses, Dissertations, and Problem Reports. 1108.