1972 年 58 巻 10 号 p. 1415-1423
The effects of fine dispersion particles on the dutility of irons with various grain sizes were investigated at -196°C. The fine dispersion particles of TiN were obtained by internal nitriding of Fe -0.1% Ti alloy. The specimens were treated in hydrogen for 72 hr at 680°C, and annealed for 48 hr at 850°C. The tensile tests were carried out at strain rate of 5.5×10-4 sec-1 and at -196°C.
The results were obtained as follows;
1) TiN particles are uniformly precipitated within grains in the recrystallized structure of Fe -0.1% Ti alloy by internal nitriding.
2) TiN particles improve the ductility of iron in the region of coarse grain size of matrix.
3) TiN particles increase the cleavage fracture stress, and make the initiation of fracture of iron difficult.
4) TiN particles don't change the fracture mode of iron.