| Title |
Research Papers / Mechanical Behaviors : Embrittlement of Fe-36 wt.%Ni Alloy in the Temperature Range of 600 ~ 1200℃ |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
Embrittlement in Fe-36 wt.%Ni alloy (invar alloy) was investigated to prevent the surface cracks formed during continuous casting operation. High temperature tensile tests were carried out in the temperature range of 600-1200℃ with in-situ solidified samples. The ductility trough was found in the temperature range of 600-850℃ in which the intergranular fracture mode was observed. This might be caused by the cavities formed along the grain boundary by diffusion and condensation of vacancies during solidification and cooling. Below about 600℃ the hot ductility increases due to insufficient time for diffusion of vacancies to the grain boundary and increased flow stress. The hot ductility above about 850℃ might result from the formation of recrystallized microstructure reducing the stress concentration at the cavities along the grain boundaries. It was also found that the embrittlement strongly depends on the strain rate and cooling rate. The increase in strain rate and cooling rate greatly improved the embrittlement. |