Dynamic recovery and dynamic recrystallizatin behaviors of AA7005 aluminium alloy (Al - Zn - Mg) during hot compression are investigated by isothermal compression testing.The interdependence of flow stress,stress, s...Dynamic recovery and dynamic recrystallizatin behaviors of AA7005 aluminium alloy (Al - Zn - Mg) during hot compression are investigated by isothermal compression testing.The interdependence of flow stress,stress, strain rate,true strain and deformation temperature for the alloy is analyzed by introduc- ing Zener-Hollomon parameter. A steady - state flow of the 7005 alloy is confirmed to be a thermal- ly activated process.which is governed by rate-controlling mechanisms of dislocations.A hyperbolic sine relationship can satisfactorily correlate temperature, strain rate with flow stress through an Arrhe- nius term that involves thermal activation parameters. The dynamic recovery mechanisms of the alloy are discussed.Cross- slip of jogged screw dislocations is the main dynamic recovery mechanism over the deformation temperatures and strain rates.Subgrains are highly developed in the originally elongat- ed grains.The size of the subgrain increases with decrease of the natural logarithm of Zener- Hol - lomon parameter.Local dynamic recrystallization is operative when the alloy is deformed at temperature of 500℃ and strain rate of 0. 001s - 1.展开更多
Discovered in S15 and some other wells, the Lower Ordovician in the northern Tarim Basin consists mainly of brown gray-dark gray very fine-fine crystalline dolomite, with a minor portion of locally light gray-white me...Discovered in S15 and some other wells, the Lower Ordovician in the northern Tarim Basin consists mainly of brown gray-dark gray very fine-fine crystalline dolomite, with a minor portion of locally light gray-white medium-coarse crystalline dolomite. Silicification can be observed in the medium-coarse dolomite, and some euhedral drusy quartz can also be found in pores and fractures of the dolomite. The homogenization temperature of the fluid inclusions in the medium-coarse dolomite is between 110 and 200°C with maximum between 140 and 190°C, and the salinity is between 10.7 and 18.5 wt.% NaCl Eq. The homogenization temperature and salinity of the fluid inclusions in the medium-coarse dolomite are similar to those in the drusy quartz. Compared with the very fine-fine dolomite, the medium-coarse phase contains relatively high Fe and Mn. The average concentration of FeO and MnO in the medium-coarse dolomite is 1.917% and 0.323%, respectively. The medium-coarse dolomite has a remarkable negative Eu anomaly, consistent with the REE pattern of the intermediate-felsic igneous rocks in the Tarim Basin. The oxygen isotopic composition of the medium-coarse dolomite is relatively lighter than that of the very fine-fine dolomite. The δ18OPDB values of the medium-coarse dolomite are between -10.35‰ and -7.31‰. The δ18OSMOW values of the fluid associated with the medium-coarse dolomite can be calculated according to homogenization temperature and oxygen isotope fractionation factor between dolomite and fluid, and the calculated values are between +4‰ and +10‰, consistent with those of the hydrothermal fluid. The medium-coarse dolomite has relatively high 87Sr/86Sr ratios as well, indi- cating an origin associated with intermediate-felsic igneous rock. The homogenization temperature, element composition, REE pattern, oxygen and strontium isotopes demonstrate that the medium-coarse dolomite is the result of recrystallization of very fine-fine dolomite under hydrothermal environment. The hydrothermal dolomite recrysta展开更多
文摘Dynamic recovery and dynamic recrystallizatin behaviors of AA7005 aluminium alloy (Al - Zn - Mg) during hot compression are investigated by isothermal compression testing.The interdependence of flow stress,stress, strain rate,true strain and deformation temperature for the alloy is analyzed by introduc- ing Zener-Hollomon parameter. A steady - state flow of the 7005 alloy is confirmed to be a thermal- ly activated process.which is governed by rate-controlling mechanisms of dislocations.A hyperbolic sine relationship can satisfactorily correlate temperature, strain rate with flow stress through an Arrhe- nius term that involves thermal activation parameters. The dynamic recovery mechanisms of the alloy are discussed.Cross- slip of jogged screw dislocations is the main dynamic recovery mechanism over the deformation temperatures and strain rates.Subgrains are highly developed in the originally elongat- ed grains.The size of the subgrain increases with decrease of the natural logarithm of Zener- Hol - lomon parameter.Local dynamic recrystallization is operative when the alloy is deformed at temperature of 500℃ and strain rate of 0. 001s - 1.
基金supported by National Basic Research Program of China (Grant No. 2005CB422103)State Key Special Project (Grant No. 2008ZX05005-001)Prospective Project of SINOPEC for Marine Oil and Gas (Grant No. G8804-07-ZS-0018)
文摘Discovered in S15 and some other wells, the Lower Ordovician in the northern Tarim Basin consists mainly of brown gray-dark gray very fine-fine crystalline dolomite, with a minor portion of locally light gray-white medium-coarse crystalline dolomite. Silicification can be observed in the medium-coarse dolomite, and some euhedral drusy quartz can also be found in pores and fractures of the dolomite. The homogenization temperature of the fluid inclusions in the medium-coarse dolomite is between 110 and 200°C with maximum between 140 and 190°C, and the salinity is between 10.7 and 18.5 wt.% NaCl Eq. The homogenization temperature and salinity of the fluid inclusions in the medium-coarse dolomite are similar to those in the drusy quartz. Compared with the very fine-fine dolomite, the medium-coarse phase contains relatively high Fe and Mn. The average concentration of FeO and MnO in the medium-coarse dolomite is 1.917% and 0.323%, respectively. The medium-coarse dolomite has a remarkable negative Eu anomaly, consistent with the REE pattern of the intermediate-felsic igneous rocks in the Tarim Basin. The oxygen isotopic composition of the medium-coarse dolomite is relatively lighter than that of the very fine-fine dolomite. The δ18OPDB values of the medium-coarse dolomite are between -10.35‰ and -7.31‰. The δ18OSMOW values of the fluid associated with the medium-coarse dolomite can be calculated according to homogenization temperature and oxygen isotope fractionation factor between dolomite and fluid, and the calculated values are between +4‰ and +10‰, consistent with those of the hydrothermal fluid. The medium-coarse dolomite has relatively high 87Sr/86Sr ratios as well, indi- cating an origin associated with intermediate-felsic igneous rock. The homogenization temperature, element composition, REE pattern, oxygen and strontium isotopes demonstrate that the medium-coarse dolomite is the result of recrystallization of very fine-fine dolomite under hydrothermal environment. The hydrothermal dolomite recrysta
