Analysis of the Socioeconomic Difficulties Affecting the Suicide Rate in Japan

This paper focuses on the drastic increase observed in the Japanese male suicide rate in the late 1990s and early 2000s and confirms unemployment and personal bankruptcy to be the associated socioeconomic factors behind the male suicide variation. Personal bankruptcy is also confirmed to be significant in the female suicide variation. The relationship is confirmed through a pooled data analysis by a middle-aged group and by prefecture. Further, the paper focused on the association between the unemployment rate and suicide mortality by incorporating the reasons for unemployment in the monthly regression. Next, we identified a significant association between male suicide variations and changes in some of the reasons for being unemployed. The interpretation of the results implies that the risk of unemployment among men has been mitigated by the unemployment insurance rather than the bias in the reasons reported and/or mental disorder in Japan.

Determination of the interface energies of spherical, cuboidal and octahedral face-centered cubic precipitates in Cu-Co, Cu-Co-Fe and Cu-Fe alloys

金沢大学理工研究域機械工学系The coarsening theory of a spherical particle in a ternary alloy developed by Kuehmann and Voorhees (KV) has been generalized to any centro-symmetric particle. A classical thermodynamic analysis reveals that the generalized KV theory enables us to estimate the interface energy of a particle with a fixed shape, even if the shape of the particle is not controlled by minimization of the interface energy. Data on the coarsening of spherical, {0 0 1}-faceted cuboidal and {1 1 1}-faceted octahedral precipitates in a Cu-Co alloy, a Cu-Fe alloy, and three Cu-Co-Fe alloys with different Co and Fe contents during aging at 873-973 K have been collected by transmission electron microscopy and electrical resistivity. By applying the generalized KV theory to the experimental data, the energies of sphere, {0 0 1} and {1 1 1} interfaces have been determined. Their energies increase with increasing the Fe composition in the alloys. © 2009 Acta Materialia Inc

Coarsening of δ-Ni2Si precipitates in a Cu-Ni-Si alloy

金沢大学理工研究域機械工学系The coarsening behavior of rod-shaped and spherical δ-Ni 2Si precipitates in a Cu-1.86 wt% Ni-0.45 wt% Si alloy during aging at 823-948 K has been investigated by measuring both precipitate size by transmission electron microscopy (TEM) and solute concentration in the Cu matrix by electrical resistivity. The rod-shaped δ precipitates have an elongated shape along 〈5̄58〉m and a {110}m habit-plane facet. The coarsening theory of a spherical precipitate in a ternary alloy developed by Kuehmann and Voorhees (KV) has been modified to a case of rod-shaped precipitates. The coarsening kinetics of average size of the rod-shaped and spherical δ precipitates with aging time t obey the t 1/3 time law, as predicted by the modified KV theory. The kinetics of depletion of the supersaturation with t are coincident with the predicted t -1/3 time law. Application of the modified KV theory has enabled calculation of the energies of sphere, {110}m and rod-end interfaces from the data on coarsening alone. The energy of the {110}m interface having a high degree of coherency to the Cu matrix is estimated to be 0.4 J m-2, the incoherent sphere-interface energy 0.6 J m-2, and the rod-end interface energy 5.2 J m-2. © 2011 Springer Science+Business Media, LLC

Effects of microstructures on fatigue behavior of an Al-Mg-Sc alloy at an elevated temperature

Polycrystalline Al-1wt%Mg-0.27wt%Sc alloys bearing Al3Sc particles with different average sizes of 4 and 11nm Polycrystalline Al-1wt%Mg-0.27wt%Sc alloys bearing Al3Sc particles with different average sizes of 4 and 11nm in diameter have been cyclically deformed at 423K under various constant stress amplitudes, and the relationship between fatigue characteristics and microstructure of the alloy has been investigated. The specimen bearing 11 nm particles exhibited a cyclic hardening to saturation, while in specimens with the small particles a cyclic softening was observed after initial hardening. In the specimen with large particles, dislocations were uniformly distributed under all applied stress amplitudes, whereas the specimens bearing small particles, in which cyclic softening occurred exhibited clearly developed slip bands. The cyclic softening for the latter specimen was explained by particle shearing within the strongly strained slip bands. The width of precipitate free zones (PFZs) has been found to be one of the factors affecting the fatigue life of the specimens at 423K. The two-step aging decreases the width of PFZs, resulting in increase in the fatigue life. © 2012 Trans Tech Publications, Switzerland

Precipitation process in a Cu-Ni-Be alloy

The precipitation process in an aged Cu-1.9wt%Ni-0.3wt%Be alloy has been examined by high-resolution transmission electron microscopy. The precipitation sequence found is: Guinier-Preston (G.P.) zones → γ″ → γ′ → stable γ. The disk-shaped G.P. zones and the disk-shaped γ″, γ′ and γ precipitated phases are composed of monolayers of Be atoms on {100}α of the Cu matrix and alternative Be and Ni matrix layers parallel to {100}α. The γ′\u27 phases consisting of two to eight Be-layers has a body-centered tetragonal (bct) lattice with a=b=0.24 nm and c=0.28 nm. The γ′ or γ phase is bct with a=b=0.24 nm and c=0.26 nm or a=b=0.26 nm and c=0.27 nm. The γ′\u27, γ′ or γ phase aligns with the matrix according to the Bain orientation relationship. The growth kinetics of disk-shaped γ precipitates on aging at 500°C has been also investigated. The {001}α habit planes of the γ precipitates migrate by a ledge mechanism. The average thickness of the γ disks increases with aging time t as t1/2. An analysis of experimental data using a kinetic model yields the diffusivity of solute in the Cu matrix, which is in agreement with the reported diffusivity of Ni in Cu. © (2011) Trans Tech Publications

Fatigue behavior and microstructure of an Al-Mg-Sc alloy at an elevated temperature

金沢大学理工研究域機械工学系Al-Mg-Sc alloy polycrystals bearing Al3Sc particles with different sizes, i.e. 4, 6 and 11 nm in diameter, have been cyclically deformed at 423 K under constant plastic-strain amplitudes, and the microstructural evolution has been investigated in relation to the stress-strain response. Cyclic softening after initial hardening is found in specimens with small particles of 4 and 6 nm, but no cyclic softening takes place in specimens with larger particles of 11 nm. These features of cyclic deformation behavior are similar to the results previously obtained at room temperature. Transmission electron microscopy observations reveal that dislocations are uniformly distributed under all applied strain amplitudes in the specimens containing large particles of 11 nm, whereas slip bands are formed in the cyclically softened specimens bearing smaller particles. The cyclic softening is explained by a loss of particle strength through particle shearing within strongly strained slip bands. The 6 and 11 nm Al3Sc particles have a stronger retardation effect on the formation of fatigue-induced stable dislocation structure than 4 nm particles at 423 K. © 2010 IOP Publishing Ltd