An Internal-State-Variable-Based Continuous Dynamic Recrystallization Model for Thermally Deformed TC18 Alloy.

Continuous dynamic recrystallization (CDRX) is widely acknowledged to occur during hot forming and plays a significant role in microstructure development in alloys with moderate to high stacking fault energy. In this work, the flow stress and CDRX behaviors of the TC18 alloy subjected to hot deformation across a wide range of processing conditions are studied. It is observed that deformation leads to the formation of new low-angle grain boundaries (LAGBs).

Fatigue Strength Improvement of Laser-Directed Energy Deposition 316L Stainless Steel with In Situ Ultrasonic Rolling by Preliminary Investigation.

In this study, to improve the fatigue strength of the LDED (laser-directed energy deposition) 316L stainless steel, an in situ ultrasonic rolling technology is developed to assist the laser-directed energy deposition process (LDED-UR). The microstructural characteristics and fatigue behavior are comprehensively discussed. The results show that the average size of pores of the LDED-UR alloy is about 10.

Effects of Crystal Orientation and External Stress on the Static Recrystallization Behavior of an Ni-Based Single-Crystal Superalloy.

The deformation mechanism and static recrystallization (SRX) behavior of an Ni-based single-crystal superalloy are investigated. Indentation tests were performed to investigate the effects of crystal orientation and external stress on SRX behavior. Following solution heat treatment, the depth of the SRX layer below the indentation increases with a deviation angle (β) from the [001] orientation.

High-Temperature Tensile Characteristics of an Al-Zn-Mg-Cu Alloy: Fracture Characteristics and a Physical Mechanism Constitutive Model.

High-temperature tensile tests were developed to explore the flow features of an Al-Zn-Mg-Cu alloy. The fracture characteristics and microstructural evolution mechanisms were thoroughly revealed. The results demonstrated that both intergranular fractures and ductile fractures occurred, which affected the hot tensile fracture mechanism.

Effects of Aging Treatment on the Microstructures and Mechanical Properties of a TC18 Alloy.

In the present work, the effects of aging treatment on the microstructures of a TC18 alloy are studied. The influence of aging treatment on the tensile properties and failure mechanisms is systematically analyzed. It is found that the size and morphology of the primary α (α) phases are insensitive to aging temperature and time.

High-Temperature Compression Behaviors and Constitutive Models of a 7046-Aluminum Alloy.

High-temperature forming behaviors of a 7046-aluminum alloy were investigated by hot compression experiments. The microstructural evolution features with the changes in deformation parameters were dissected. Results indicated the formation of massive dislocation clusters/cells and subgrains through the intense DRV mechanism at low compression temperature.

Hot Deformation Behavior of Hastelloy C276 Alloy: Microstructural Variation and Constitutive Models.

Isothermal deformation experiments of the Hastelloy C276 alloy were executed using the Gleeble-3500 hot simulator at a temperature range of 1000-1150 °C and a strain rate range of 0.01-10 s. Microstructural evolution mechanisms were analyzed via transmission electron microscope (TEM) and electron backscatter diffraction (EBSD).

Dislocation Substructures Evolution and an Informer Constitutive Model for a Ti-55511 Alloy in Two-Stages High-Temperature Forming with Variant Strain Rates in β Region.

The high-temperature compression characteristics of a Ti-55511 alloy are explored through adopting two-stage high-temperature compressed experiments with step-like strain rates. The evolving features of dislocation substructures over hot, compressed parameters are revealed by transmission electron microscopy (TEM). The experiment results suggest that the dislocations annihilation through the rearrangement/interaction of dislocations is aggravated with the increase in forming temperature.

Soil heavy metal pollution from Pb/Zn smelting regions in China and the remediation potential of biomineralization.

Smelting activities pose serious environmental problems due to the local and regional heavy metal pollution in soils they cause. It is therefore important to understand the pollution situation and its source in the contaminated soils. In this paper, data on heavy metal pollution in soils resulting from Pb/Zn smelting (published in the last 10 years) in China was summarized.

Effect of Deformation Parameters of an Initial Aged GH4169 Superalloy on Its Microstructural Evolution during a New Two-Stage Annealing.

This study aims to explore the effect of deformation parameters on microstructure evolution during the new two-stage annealing method composed of an aging treatment (AT) and a cooling recrystallization annealing treatment (CRT). Firstly, the hot compressive tests with diverse deformation parameters were finished for an initial aged deformed GH4169 superalloy. Then, the same two-stage annealing method was designed and carried out for the deformed samples.

Modeling Dynamic Recrystallization Behavior in a Novel HIPed P/M Superalloy during High-Temperature Deformation.

The dynamic recrystallization (DRX) features and the evolution of the microstructure of a new hot isostatic pressed (HIPed) powder metallurgy (P/M) superalloy are investigated by hot-compression tests. The sensitivity of grain dimension and DRX behavior to deformation parameters is analyzed. The results reveal that the DRX features and grain-growth behavior are significantly affected by deformation conditions.

Evolution of Annealing Twins in a Hot Deformed Nickel-Based Superalloy.

The hot deformation characteristics of a GH4169 superalloy are investigated at the temperature and strain rate ranges of 1193-1313 K and 0.01-1 s, respectively, through Gleeble-3500 simulator. The hot deformed microstructures are analyzed by optical microscopy (OM), transmission electron microscopy (TEM), and electron backscattered diffraction (EBSD) technology.

Intercomparison of global terrestrial carbon fluxes estimated by MODIS and Earth system models.

Earth system models (ESMs) have been widely used to simulate global terrestrial carbon fluxes, including gross primary production (GPP) and net primary production (NPP). Assessment of such GPP and NPP products can be valuable for understanding the efficacy of certain ESMs in simulating the global carbon cycle and future climate impacts. In this work, we studied the model performance of 22 ESMs participating in the fifth and sixth phases of the Coupled Model Intercomparison Project (CMIP5 and CMIP6) by comparing historical GPP and NPP simulations with satellite data from MODIS and further evaluating potential model improvement from CMIP5 to CMIP6.

Microstructure Evolution and a Unified Constitutive Model of Ti-55511 Alloy Compressed at Stepped Strain Rates.

The flow behavior and microstructure change of the Ti-55511 alloy are investigated by thermal compression experiments with stepped strain rates. The phase transformation features, the dynamic recrystallization (DRX) behavior of the β matrix, the dynamic spheroidization mechanism of the lamellar α phase and the evolution of the β sub-grain size are quantitatively analyzed. A unified constitutive model is constructed to characterize the hot deformation features of the Ti-55511 alloy.

Microstructural Variation and a Physical Mechanism Model for a Ti-55511 Alloy during Double-Stage Hot Deformation with Stepped Strain Rates in the β Region.

The microstructural variation and high-temperature flow features of a Ti-55511 alloy in the β region are studied by utilizing double-stage compression with a stepped strain rate. The results demonstrate that the stresses in the latter stage of hot compression markedly reduce as the strain at the previous stage or the strain rate at the previous/latter stage drops. Moreover, the annihilation/interaction of substructures is promoted, and the distinct refinement of the dynamic recrystallization (DRX) in the β grain can be found.

Effects of Aging Treatment on Corrosion Behavior of a Tensile Deformed Al-Cu-Mn-Fe-Zr Alloy in 3.5% NaCl Solution.

In this paper, the effects of an aging treatment on the corrosion resistance/mechanism of a tensile deformed Al-Cu-Mn-Fe-Zr alloy are investigated. The impedance magnitude and polarization resistance increase, while the corrosion current decreases with the increased aging time and temperature. The discontinuously-distributed precipitates and precipitation-free zone, which can cut the corrosion channels, appear at grain boundaries when the temperature is relatively high and the aging time is relatively long.

Effects of Double-Stage Annealing Parameters on Tensile Mechanical Properties of Initial Aging Deformed GH4169 Superalloy.

This study takes large size samples after hot-upsetting as research objects and aims to investigate the optimization double-stage annealing parameters for improving the mechanical properties of hot-upsetting samples. The double-stage annealing treatments and uniaxial tensile tests for hot-upsetting GH4169 superalloy were finished firstly. Then, the fracture mode was also studied.

Strengthening of a Near β-Ti Alloy through β Grain Refinement and Stress-Induced α Precipitation.

Near β-Ti alloys with high strength and good ductility are desirable for application in aviation and aerospace industries. Nevertheless, strength and ductility are usually mutually exclusive in structural materials. Here we report a new thermo-mechanical process, that is, the alloy was cross-rolled in β field then aged at 600 °C for 1 h.

Xyloketal B exerts antihypertensive effect in renovascular hypertensive rats via the NO-sGC-cGMP pathway and calcium signaling.

Xyloketal B (Xyl-B) is a novel marine compound isolated from mangrove fungus Xylaria sp. (No 2508). We previously showed that Xyl-B promoted endothelial NO release and protected against atherosclerosis through the Akt/eNOS pathway.

Phochrodines A-D, first naturally occurring new chromenopyridines from mangrove entophytic fungus Phomopsis sp. 33.

Four new chromenopyridine derivatives, phochrodines A-D (1-4), were identified from mangrove entophytic fungus Phomopsis sp. 33# by means of various modern chromatographic, spectroscopic and single crystal X-ray diffraction techniques. Compounds 1-4 with an unusual 5H-chromeno[4,3-b]pyridine skeleton were the first naturally occurring chromenopyridines.

α-Glucosidase inhibitory and cytotoxic botryorhodines from mangrove endophytic fungus Trichoderma sp. 307.

One new depsidone, botryorhodine H (1), together with three known analogues, botryorhodines C, D and G (2-4), were obtained from the mangrove endophytic fungus Trichoderma sp. 307 by co-culturing with Acinetobacter johnsonii B2. Structures were determined by 1D and 2D NMR analyses and high-resolution mass spectrum.

Induction of Diverse Bioactive Secondary Metabolites from the Mangrove Endophytic Fungus Trichoderma sp. (Strain 307) by Co-Cultivation with Acinetobacter johnsonii (Strain B2).

Two new sesquiterpenes, microsphaeropsisin B () and C (), and two new de--methyllasiodiplodins, (3, 7)-7-hydroxy-de--methyllasiodiplodin () and (3)-5-oxo-de--methyllasiodiplodin (), together with one new natural product () and twelve known compounds (, -), were isolated from the co-cultivation of mangrove endophytic fungus sp. 307 and aquatic pathogenic bacterium B2. Their structures, including absolute configurations, were elucidated by extensive analysis of spectroscopic data, electronic circular dichroism, Mo₂(AcO)₄-induced circular dichroism, and comparison with reported data.

Phomopsichin A-D; Four New Chromone Derivatives from Mangrove Endophytic Fungus Phomopsis sp. 33.

Four new chromone derivatives, phomopsichins A-D (-), along with a known compound, phomoxanthone A (), were isolated from the fermentation products of mangrove endophytic fungus sp. 33#. Their structures were elucidated based on comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction or theoretical calculations of electronic circular dichroism (ECD).