The evolution of crystallographic texture during plastic deformation was investigated in Zircaloy... more The evolution of crystallographic texture during plastic deformation was investigated in Zircaloy-2 using X-ray and metallographic techniques. Inverse pole figures, the resolved fraction of basal poles, and the volume fraction of twinned material, were determined as a function of plastic strain for several strain paths and initial textures at 298 K and 623 K. incremental transverse platic strain ratios (R) were mesured as a function of plastic strain. Texture rotation occurs early in the deformation process, after as little as 1.5% plastic strain. For compressive plastic strains, the resolved fraction of basal poles increases in the direction parallel to the strain axis. For tensile plastic strains, the resolved fraction of basal poles decreases in the direction parallel to the strain axis. The rate of change of the resolved fraction of basal poles with plastic strain is a function of the initial resolved fraction of basal poles. The texture rotation can be explained by considering the operation of the principal tensile twinning systems, (ioi2)(ioll).
... Res. 3 (1964) 88. [28] RO Ritchie. WL Server, and RA Wullaert. Met. ... [76] RH Priest. RH Ch... more ... Res. 3 (1964) 88. [28] RO Ritchie. WL Server, and RA Wullaert. Met. ... [76] RH Priest. RH Charnock and AT Stewart, ASTM STP 782 (1982) 475. [77] FA Smidt Jr.. JR Hawthorne and V. Provenzano, ASTM STP 725 (1981) 269. [78] M. Suzuki, K. Fukaya, T. Kodaire and T. Oku. ...
Blends containing 3 wt % low molecular weight polybutadiene ( P B ) in a polystyrene (PS) matrix ... more Blends containing 3 wt % low molecular weight polybutadiene ( P B ) in a polystyrene (PS) matrix were prepared via a precipitation technique that yielded spherical, submicron pools of PB. Tensile specimens made from these blends were then irradiated with high energy electrons in air a t dose levels from 0 to 70 Mrads. The blends, which previously showed high levels of toughness approaching that of high impact PS, lost all enhanced toughness when irradiated above 10 Mrads. Analysis of pure PS specimens irradiated over the dose range from 0 to 45 Mrads showed no appreciable dependence of mechanical behavior on dose level. Molecular weight studies of the polybutadiene demonstrated only a very modest increase in molecular weight in the dose range studied here; therefore, reduced mobility of the P B in the blends was not the reason for the dramatic drop in toughness with radiation dose. It was concluded that radiation-induced scission of the PS near the surface of the blends resulted in a significant local reduction in molecular weight. This degraded layer led to premature craze failure and hence a low level of toughness. It was demonstrated that the absence of oxygen during the irradiation process or the removal of the scissioned surface layer via mechanical abrasion resulted in a recovery of toughness. 0
Esopo foi um fabulista grego, nascido na Trácia no século VI a.C.. Personagem quase mítico, sabe-... more Esopo foi um fabulista grego, nascido na Trácia no século VI a.C.. Personagem quase mítico, sabe-se que foi um escravo libertado pelo seu último senhor, o filósofo Janto (Xanto).
The evolution of crystallographic texture during plastic deformation was investigated in Zircaloy... more The evolution of crystallographic texture during plastic deformation was investigated in Zircaloy-2 using X-ray and metallographic techniques. Inverse pole figures, the resolved fraction of basal poles, and the volume fraction of twinned material, were determined as a function of plastic strain for several strain paths and initial textures at 298 K and 623 K. incremental transverse platic strain ratios (R) were mesured as a function of plastic strain. Texture rotation occurs early in the deformation process, after as little as 1.5% plastic strain. For compressive plastic strains, the resolved fraction of basal poles increases in the direction parallel to the strain axis. For tensile plastic strains, the resolved fraction of basal poles decreases in the direction parallel to the strain axis. The rate of change of the resolved fraction of basal poles with plastic strain is a function of the initial resolved fraction of basal poles. The texture rotation can be explained by considering the operation of the principal tensile twinning systems, (ioi2)(ioll).
... Res. 3 (1964) 88. [28] RO Ritchie. WL Server, and RA Wullaert. Met. ... [76] RH Priest. RH Ch... more ... Res. 3 (1964) 88. [28] RO Ritchie. WL Server, and RA Wullaert. Met. ... [76] RH Priest. RH Charnock and AT Stewart, ASTM STP 782 (1982) 475. [77] FA Smidt Jr.. JR Hawthorne and V. Provenzano, ASTM STP 725 (1981) 269. [78] M. Suzuki, K. Fukaya, T. Kodaire and T. Oku. ...
Blends containing 3 wt % low molecular weight polybutadiene ( P B ) in a polystyrene (PS) matrix ... more Blends containing 3 wt % low molecular weight polybutadiene ( P B ) in a polystyrene (PS) matrix were prepared via a precipitation technique that yielded spherical, submicron pools of PB. Tensile specimens made from these blends were then irradiated with high energy electrons in air a t dose levels from 0 to 70 Mrads. The blends, which previously showed high levels of toughness approaching that of high impact PS, lost all enhanced toughness when irradiated above 10 Mrads. Analysis of pure PS specimens irradiated over the dose range from 0 to 45 Mrads showed no appreciable dependence of mechanical behavior on dose level. Molecular weight studies of the polybutadiene demonstrated only a very modest increase in molecular weight in the dose range studied here; therefore, reduced mobility of the P B in the blends was not the reason for the dramatic drop in toughness with radiation dose. It was concluded that radiation-induced scission of the PS near the surface of the blends resulted in a significant local reduction in molecular weight. This degraded layer led to premature craze failure and hence a low level of toughness. It was demonstrated that the absence of oxygen during the irradiation process or the removal of the scissioned surface layer via mechanical abrasion resulted in a recovery of toughness. 0
Esopo foi um fabulista grego, nascido na Trácia no século VI a.C.. Personagem quase mítico, sabe-... more Esopo foi um fabulista grego, nascido na Trácia no século VI a.C.. Personagem quase mítico, sabe-se que foi um escravo libertado pelo seu último senhor, o filósofo Janto (Xanto).
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