- 著者
- Hiroshi Sawamura
- 出版者
- The Japan Institute of Metals
- 雑誌
- Transactions of the Japan Institute of Metals (ISSN:00214434)
- 巻号頁・発行日
- vol.13, no.4, pp.225-230, 1972 (Released:2007-06-01)
- 参考文献数
- 10
- 被引用文献数
- 2 5
The present investigation has been carried out in order to revise the results of the present author’s previous investigation. For this purpose, the new data about the heat of fusion of most metallic elements have been used.Almost the same results as those of the previous investigation have been obtained. In the present investigation, however, a new fact has been found that the relation in question in metallic elements belonging to CPHex should be considered in two different regions separately, the one being the region of the lower melting temperature and the other the region of the higher melting temperature.The following predictions have been deduced from the present investigation :(1) The structures of the liquid phases in equilibrium with the solid metallic elements (except Al) belonging to FCC at their melting temperatures will be the same with each other, independently of the species of metallic element, because the relation between the entropy of fusion or the heat of fusion of these metallic elements and their melting temperature is represented exactly by a straight line or a smooth curve. The same thing will be said about the metallic elements belonging to other types of space lattice.(2) Though the space lattice of the following metallic elements is considered to be BCC at present, most of them belong probably to FCCZr, V, Ti, Mn, Eu.(3) Though the crystal structure of the following metallic elements is unknown at present, they belong probably to FCC or CPHexPa, Ac, U, Sm, Pm, Nd, Pr, La, Ce, Ra.
- 著者
- Kaieda Yoshinari Oguchi Atsushi
- 出版者
- 社団法人 日本金属学会
- 雑誌
- Transactions of the Japan Institute of Metals (ISSN:00214434)
- 巻号頁・発行日
- vol.22, no.2, pp.83-95, 1981
- 被引用文献数
- 4
In order to clarify the effect of high hydrostatic pressure on the brittle fracture stress, the three-point bending tests have been carried out for an Fe–Cr alloy (σ phase) containing about 47%Cr and 0.7%Si at atmospheric pressure and under 800 MPa at temperatures up to 1200 K. In the temperature range from room temperature to 1140 K, the specimens remained in the σ phase and the transgranular cleavage fracture occurred under both pressures. By scanning electron microscopy, the fracture surface was found to comprise the river pattern and the Wallner lines. The fracture stress at atmospheric pressure increased gradually with increasing temperature to about 1000 K and increased rapidly at higher temperatures. The same tendency was observed in the tests under 800 MPa but the fracture stress under 800 MPa was always higher than that at atmospheric pressure, and the difference between these stresses became larger at temperatures higher than about 1000 K. From a consideration of the stress condition around a crack, a formula σ<I><SUB>FP</SUB></I>=σ<SUB><I>F</I>0</SUB>+<I>P</I>⁄<I>K</I><SUB>σ</SUB> was proposed to represent the influence of hydrostatic pressure on the brittle fracture stress at low temperatures, where σ<SUB><I>F</I>0</SUB> and σ<I><SUB>FP</SUB></I> are the fracture stresses at atmospheric pressure and under high pressure, <I>P</I> is the pressure in positive sign and <I>K</I><SUB>σ</SUB> is the stress concentration factor at the crack. At higher temperatures, <I>K</I><SUB>σ</SUB> was replaced by Neuber’s plastic stress concentration factor <I>K</I><SUB>σ</SUB><SUP>*</SUP>.