JOPSS - Search Results

Journal Articles

Novel pressure phase diagram of heavy fermion superconductor CePt $_{3}$ Si investigated by ac calorimetry

Tateiwa, Naoyuki; Haga, Yoshinori; Matsuda, Tatsuma; Ikeda, Shugo; Yasuda, Takashi*; Takeuchi, Tetsuya*; Settai, Rikio*; Onuki, Yoshichika

Journal of the Physical Society of Japan, 74(7), p.1903 - 1906, 2005/07

https://doi.org/10.1143/JPSJ.74.1903

Times Cited Count：71 Percentile：89.01(Physics, Multidisciplinary)

The pressure dependences of the antiferromagnetic and superconducting transition temperatures have been investigated by ac heat capacity measurement under high pressures for the heavy-fermion superconductor CePtSi without inversion symmetry in the tetragonal structure. The Nel temperature $T_{rm N}$ = 2.2 K decreases with increasing pressure and becomes zero at the critical pressure $P_{rm AF}$ 0.6 GPa. On the other hand, the superconducting phase exists in a wider pressure region from ambient pressure to about 1.5 GPa. The pressure phase diagram of CePtSi is thus very unique and has never been reported before for other heavy fermion superconductors.

Journal Articles

Multiaxial creep behavior of nickel-base heat-resistant alloys Hastelloy XR and Ni-Cr-W superalloy at elevated temperatures

Tsuji, Hirokazu; Nishi, Hiroshi; Kaji, Yoshiyuki; Muto, Yasushi; Penkalla, H. J.*; Schubert, F.*

Proceedings of the 7th International Conference on Creep and Fatigue at Elevated Temperatures (CREEP7), p.101 - 106, 2001/06

A series of uniaxial and multiaxial creep tests was carried out on Hastelloy XR and Ni-Cr-W superalloy, which were developed as the high temperature structural materials for nuclear application at the JAERI, in order to investigate multiaxial creep behaviors of these materials. Norton's creep law and von Mises' flow rule were applied to the prediction of multiaxial creep behavior of a tube under some significant loading condition. In most cases the multiaxial creep behavior of these materials were successfully described with the constitutive equations based on the material parameter fitting uniaxial creep test results, though a few exceptional cases were observed. The present study has revealed that the method based on Norton's creep law and von Mises' flow rule are basically applicable for the description of the multiaxial creep behavior for Hastelloy XR and Ni-Cr-W superalloy as the conventional design method.

Journal Articles

Inelastic constitutive equation in Alloy800H

Kaji, Yoshiyuki; Kikuchi, Kenji; Penkalla, H. J.*

Proceedings of the 7th International Conference on Creep and Fatigue at Elevated Temperatures (CREEP7), p.179 - 183, 2001/06

A creep constitutive equation in Alloy800H was developed at 700, 800 and 850oC. In the equation, the inelastic strain rate is written in the form of a flow equation of the Norton-Bailey type and the hardening during deformation under various loads is induced by an internal stress which is subdivided into back stress and friction stress. The back stress represents a conservative part of the creep resistance while the friction stress includes all the dissipative parts in the internal structure such as grain boundary sliding, diffusion and interaction between dislocation and precipitation. Parameters were determined by the deformation properties for creep under constant stress conditions at each temperature. Deformation analyses show a good agreement between calculations and experimental results for creep tests at each temperature.

Journal Articles