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X P Zhang - One of the best experts on this subject based on the ideXlab platform.
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microstructure bonding strength and thickness Ratio of al mg al alloy laminated composites prepared by hot rolling
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: X P Zhang, Sylvie Castagne, T H Yang, Jing Tao WangAbstract:In this study, 7075 Al/AZ31B Mg/7075 Al laminated composites were prepared by hot roll bonding method. Microstructure and bonding strength of the experimental laminated composites, and thickness Ratio of the constituent layers after hot rolling were evaluated. Effects of Reduction Ratio and rolling temperature on the microstructure, bonding strength and thickness Ratio were also studied. Dynamic recrystallization microstructures were observed in the composite. The bonding strength decreased with Reduction Ratio and rolling temperature due to the increase in the grain size and diffusion layer width with the Reduction Ratio and rolling temperature. The maximal bonding strength of the experimental laminated composite was 66 MPa. The thickness fraction of the Mg alloy plate after hot rolling decreased with the Reduction Ratio and rolling temperature.
Jeongho Han - One of the best experts on this subject based on the ideXlab platform.
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effects of cold rolling Reduction Ratio on microstructures and tensile properties of intercritically annealed medium mn steels
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Min Tae Kim, Tak Min Park, Kyeong Ho Baik, Wonseok Choi, Jeongho HanAbstract:Abstract The relationship between the cold rolling Reduction Ratio of medium-Mn steel before annealing, and the microstructure and tensile properties after annealing was investigated. The model alloy (Fe 8Mn–0.2C 3Al (wt.%) steel) was cold-rolled at different Reduction Ratios (between 0% and 60%) prior to intercritical annealing (IA) at 720 °C for 30 min. An increase in the cold rolling Reduction Ratio caused the nanolaminate morphology (α′ tempered martensite (α′temp) and retained austenite (γR) phases) to change to a nanoscale globular morphology (ferrite (α) and γR phases). However, the volume fraction of the γR phase, width of the nanolaminate phase, and the diameter of the nanoscale globular phase remained essentially unchanged, regardless of the cold rolling Reduction Ratio. The nanolaminate morphology exhibited a crystallographic orientation characterized by the absence of α′ recrystallization and austenite memory effect, that is preferable to the nanoscale globular morphology. The steel that was cold-rolled at a higher Reduction Ratio had a higher yield strength due to the increased slip resistance of the phases (consisting of a reduced area of the same orientation). In addition, with an increase in the cold rolling Reduction Ratio, the tensile strength and total elongation were improved owing to the more dynamic transformation- and twinning-induced plasticity in the nanoscale globular γR phase than the nanolaminate γR phase. Therefore, we have concluded that an optimized cold working prior to IA, will lead to improved mechanical properties of industrially produced medium-Mn steel.
William F Owen - One of the best experts on this subject based on the ideXlab platform.
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exploring the reverse j shaped curve between urea Reduction Ratio and mortality
Kidney International, 1999Co-Authors: William F Owen, Glenn M Chertow, Michael J Lazarus, Nancy L LewAbstract:Exploring the reverse J-shaped curve between urea Reduction Ratio and mortality. Background Although accepted worldwide as valid measures of dialysis adequacy, neither the Kt/V (urea clearance determined by kinetic modeling) nor the urea Reduction Ratio (URR) have unambiguously predicted survival in hemodialysis patients. Because the Ratio Kt/V can be high with either high Kt (clearance × time) or low V (urea volume of distribution) and V may be a proxy for skeletal muscle mass and nutritional health, we hypothesized that the increase in the relative risk of death observed among individuals dialyzed in the top 10 to 20% of URR or Kt/V values might reflect a competing risk of malnutrition. Methods A total of 3,009 patients who underwent bioelectrical impedance analysis were stratified into quintiles of URR. Laboratory indicators of nutritional status and two bioimpedance-derived parameters, phase angle and estimated total body water, were compared across quintiles. The relationship between dialysis dose and mortality was explored, with a focus on how V influenced the structure of the dose–mortality relationship. Results There were statistically significant differences in all nutritional parameters across quintiles of URR or Kt/V, indicating that patients in the fifth quintile (mean URR, 74.4 ± 3.1%) were more severely malnourished on average than patients in all or some of the other quintiles. The relationship between URR and mortality was decidedly curvilinear, resembling a reverse J shape that was confirmed by statistical analysis. An adjustment for the influence of V on URR or Kt/V was performed by evaluating the Kt-mortality relationship. There was no evidence of an increase in the relative risk of death among patients treated with high Kt. Higher Kt was associated with a better nutritional status. Conclusion We conclude that the increase in mortality observed among those patients whose URR or Kt/V are among the top 10 to 20% of patients reflects a deleterious effect of malnutrition (manifest by a reduced V) that overcomes whatever benefit might be derived from an associated increase in urea clearance. Identification of patients who achieve extremely high URR (>75%) or single-pooled Kt/V (>1.6) values using standard dialysis prescriptions should prompt a careful assessment of nutritional status. Confounding by protein-calorie malnutrition may limit the utility of URR or Kt/V as a population-based measure of dialysis dose.
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the urea Reduction Ratio and serum albumin concentRation as predictors of mortality in patients undergoing hemodialysis
The New England Journal of Medicine, 1993Co-Authors: William F Owen, Edmund G Lowrie, J M LazarusAbstract:Background Among patients with end-stage renal disease who are treated with hemodialysis, solute clearance during dialysis and nutritional adequacy are determinants of mortality. We determined the effects of Reductions in blood urea nitrogen concentRations during dialysis and changes in serum albumin concentRations, as an indicator of nutritional status, on mortality in a large group of patients treated with hemodialysis. Methods We analyzed retrospectively the demographic characteristics, mortality rate, duRation of hemodialysis, serum albumin concentRation, and urea Reduction Ratio (defined as the percent Reduction in blood urea nitrogen concentRation during a single dialysis treatment) in 13,473 patients treated from October 1, 1990, through March 31, 1991. The risk of death was determined as a function of the urea Reduction Ratio and serum albumin concentRation. Results As compared with patients with urea Reduction Ratios of 65 to 69 percent, patients with values below 60 percent had a higher risk of ...
Jing Tao Wang - One of the best experts on this subject based on the ideXlab platform.
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microstructure bonding strength and thickness Ratio of al mg al alloy laminated composites prepared by hot rolling
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2011Co-Authors: X P Zhang, Sylvie Castagne, T H Yang, Jing Tao WangAbstract:In this study, 7075 Al/AZ31B Mg/7075 Al laminated composites were prepared by hot roll bonding method. Microstructure and bonding strength of the experimental laminated composites, and thickness Ratio of the constituent layers after hot rolling were evaluated. Effects of Reduction Ratio and rolling temperature on the microstructure, bonding strength and thickness Ratio were also studied. Dynamic recrystallization microstructures were observed in the composite. The bonding strength decreased with Reduction Ratio and rolling temperature due to the increase in the grain size and diffusion layer width with the Reduction Ratio and rolling temperature. The maximal bonding strength of the experimental laminated composite was 66 MPa. The thickness fraction of the Mg alloy plate after hot rolling decreased with the Reduction Ratio and rolling temperature.
Xianghua Liu - One of the best experts on this subject based on the ideXlab platform.
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adjusting the microstructure evolution mechanical properties and deformation behaviors of fe 5 95mn 1 55si 1 03al 0 055c medium mn steel by cold rolling Reduction Ratio
Journal of materials research and technology, 2020Co-Authors: Shu Yan, Taosha Liang, Xianghua LiuAbstract:Abstract For a representative medium Mn steel with the actual chemical composition of Fe-5.95 Mn-1.55Si-1.03Al-0.055 C (wt. %), the effect of cold-rolling deformation on microstructural evolution and mechanical properties was investigated systematically. The thickness of coarse δ-ferrite grains decreases with the increase of cold-rolling Reduction, and when the cold-rolling Reduction Ratio reaches up to a certain value, these δ-ferrite grains can be broken into small pieces due to the severe plastic deformation. Additionally, a critical cold-rolling Reduction Ratio for recrystallization exists. Below this critical Reduction value, the medium Mn steel after austenite reverted transformation (ART) annealing remains lath-shaped structure originating from the initial martensitic morphology, and when recrystallization occurs, however, submicron equiaxed grains dominate. The initial microstructure before ART annealing, which is usually determined by cold-rolling Reduction, strongly influences not only the martensitic/ferritic matrix, but also reverted austenite grains. Non-recrystallization matrix promotes the formation of acicular reverted austenite, whereas recrystallization forces the austenite grains spherical and promotes the grain size of austenite homogenizing. Under the situation of non-recrystallization, the cold-rolling Reduction prior to ART annealing only has a negligible effect on the final mechanical properties. However, the occurrence of recrystallization results in not only the yielding plateau, i.e., discontinuous yielding, but also the remarkable increase of yield strength.
