Revealing the Phase Segregation and Evolution Dynamics in Binary Nanoalloys via Electron Beam-Assisted Ultrafast Heating and Cooling

ACS Nano ◽  
2022 ◽  
Author(s):  
Lei Shi ◽  
Longbing He ◽  
Lei Shangguan ◽  
Yilong Zhou ◽  
Binjie Wang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Phase Segregation ◽  
Heating And Cooling ◽  
Evolution Dynamics

Enhanced Wear Resistance of Al-15Si and ZK60-1Y Mg Alloys Induced by High Current Pulsed Electron Beam Treatment

2011 ◽  
Vol 189-193 ◽  
pp. 1204-1207 ◽  
Author(s):  
Bo Gao ◽  
Yi Hao ◽  
Gan Feng Tu ◽  
Shi Wei Li ◽  
Sheng Zhi Hao ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Electron Beam ◽  
Rapid Heating ◽  
Mg Alloys ◽  
Surface Wear ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Heating And Cooling ◽  
Melted Layer ◽  
Modification Of Materials

High current pulsed electron beam (HCPEB), a novel high-power energetic beam technology, has been developed as a useful tool for surface modification of materials. In the present work, the effect of HCPEB treatment on microstructure and wear resistance of Al-15Si and ZK60-1Y Mg alloys was investigated. The results show that a supersaturated solid solution of (Al) and (Mg) is formed on top surface of melted layer induced by rapid heating and cooling during HCPEB process. In addition, the melted layer of approximately 5~11μm thickness is obtained on the ZK60-1Y Mg alloy surface. Wear resistance of Al-15Si and ZK60-1Y Mg alloys are significantly improved after HCPEB treatment. It is demonstrated that HCPEB technology has a good application future in enhancing surface properties of Al-Si and Mg alloys.

scholarly journals The Crystallization Mechanism of Zr-Based Bulk Metallic Glass during Electron Beam Remelting

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3488 ◽  
Author(s):  
Xiaopeng Li ◽  
Zeyu Zhang ◽  
Yi Yang ◽  
Jikang Fan ◽  
Jian Kong ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Welding ◽  
Amorphous State ◽  
Welding Process ◽  
Critical Conditions ◽  
Heating Process ◽  
The Finite Element Method ◽  
Scanning Calorimetry ◽  
Heating And Cooling ◽  
Size Limitation

Bulk metallic glasses (BMGs) are promising for multifunctional and structural application in different industries. However, the limited size of BMGs hinders their further application. The welding of BMGs has shown the possibility of getting rid of the casting size limitation. The heat-affected zone (HAZ) and fusion zone (FZ) often undergo severe crystallization during the welding process. It is still unclear whether the crystallization occurs during the heating process or the cooling process. To figure out the crystallization mechanisms of Zr-based BMGs during the electron beam welding process, the Zr-based BMGs with the composition of Zr41.2Ti13.8Cu12.5Ni10Be22.5 were remelted by electron beam. The microstructures of the HAZ and the remelting zone (RZ) were analyzed. The thermal field of the electron beam welding was obtained by the finite element method (FEM). The critical conditions for crystallization during the heating and cooling processes were obtained by differential scanning calorimetry (DSC) and the Kissinger equation. The results show that the Zr41.2Ti13.8Cu12.5Ni10Be22.5 in the HAZ undergoes severe crystallization, while the Zr41.2Ti13.8Cu12.5Ni10Be22.5 in RZ keeps amorphous state after the remelting process. The low cooling rate in the HAZ is responsible for its crystallization.

Effect of High-Current Pulsed Electron Beam Processing of Zr-1%Nb Alloy on Its Oxidation Kinetics at 1200C in Air and Steam

CORROSION ◽  
10.5006/3942 ◽  
2021 ◽  
Author(s):  
Mikhail Slobodyan ◽  
Konstantin Ivanov ◽  
Maxim Elkin ◽  
Vasiliy Klimenov ◽  
Sergey Pavlov ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Current ◽  
Surface Layers ◽  
Research Directions ◽  
Temperature Oxidation ◽  
Pulsed Electron Beam ◽  
Electron Beam Processing ◽  
Heating And Cooling ◽  
Loss Of Coolant ◽  
Kinetics Of

The paper reports the effect of high-current pulsed electron beam (HCPEB) processing of the Zr-1%Nb alloy, as one of the most widely used in water-cooled nuclear reactors, on the kinetics of its oxidation at 1200 °C in air and steam (these conditions are typical for potential loss-of-coolant accidents). It was shown that HCPEB processing caused a change in the surface morphology of the samples. In particular, craters with diameters of about 100 μm were found on the modified surfaces. They had initiated at an energy density of 5 J/cm2 and were characterized by relevant reliefs with microcracks. After HCPEB processing at 10 J/cm2, the craters were deeper with fractured surface layers. In addition, a pronounced surface relief corresponding to quenched martensitic microstructures was observed on the modified sample surfaces that had formed due to high heating and cooling rates. Due to sufficient degradation of the sample surfaces after HCPEB processing at 10 J/cm2, the kinetics of high-temperature oxidation was estimated only for the as-received samples and ones treated at 5 J/cm2. It was found that the as-received samples showed slightly greater weight gain levels in both air and steam environments, which fully correlated with the thickness ratio of the oxide, α-Zr(O) and prior-β layers. These phenomena and further research directions were discussed.

Temperature Field Simulation for Aluminum Alloy Surface Modification by Scanning Electron Beam

2010 ◽  
Vol 97-101 ◽  
pp. 1404-1407
Author(s):  
Pei Xin Sun ◽  
Rong Wang ◽  
De Qiang Wei
Keyword(s):  
Surface Modification ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Element Model ◽  
Melting Zone ◽  
Scanning Electron Beam ◽  
Heating And Cooling ◽  
Axis Length ◽  
Aluminum Alloy Surface ◽  
Scanning Electron

According to the actual experimental condition and theoretical analysis, a finite element model was established to describe the surface modification process of scanning electron beam of 6A02 aluminum alloy. The phase change process and thermal radiation were considered in the simulation. The temperature simulation revealed the ultrahigh rate of the heating and cooling, rapid melting and re-solidification within seconds in the range of millimeters in depth. The calculated melting zone was an irregular semicircle, the x-axis length was about 2.9mm, and the axial depth was about 1.4mm. This research will predict the melting condition.

A New 1000°C Double Tilt Stage for the Hitachi 650 kV Microscope

1974 ◽  
Vol 32 ◽  
pp. 442-443
Author(s):  
W. Worthington ◽  
T. Kosel ◽  
R. Sinclair
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
High Temperature ◽  
Electric Current ◽  
Heating Element ◽  
Design Criteria ◽  
Original Design ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Specimen Holder

A new 1000°C specimen holder has been developed for the Hu-650 electron microscope and is interchangeable with other holders for the recently designed orthagonal drive tilting stage. The requirements for the high temperature device were as follows: 1. An orthogonal double-tilt stage with all original design criteria maintained(1). 2. Capability of heating standard (3mm. dia.) metallurgical specimens to 1000°C. 3. Geometry and materials should be such that stage and microscope components shall not be damaged by heat from the specimen holder. 4. The electric current to the heating element shall impart a minimum effect upon the microscope electron beam. 5. Heating and cooling rates to be as rapid as possible.

Temperature Field Simulation of Electron Beam Cladding W Coating on Cu Substrate

2015 ◽  
Vol 1094 ◽  
pp. 331-334
Author(s):  
Li Wan ◽  
Yi Ping Huang ◽  
Rui Bin Zhang ◽  
Hai Hua Yu ◽  
Hang Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Electron Beam ◽  
Cooling System ◽  
Tungsten Powder ◽  
Element Model ◽  
Field Calculation ◽  
Element Analysis ◽  
Heating And Cooling ◽  
Calculation Results

A 3D Finite Element Model of the Temperature Field for Electron Beam Cladding of Pre-Tungsten Powder on the Surface of the Copper Block was Established, According to the Actual Situation of the Electron Beam Cladding Process, Based on Finite Element Analysis Software ANSYS Workbench, Analyzed the Temperature Field Distribution of the Electron Beam Cladding Process. Temperature Field Calculation Results Showed that the Cladding Process Heating and Cooling Speed was up to 103-104°C/s, and the Surface Temperature Increased Rapidly, while the Temperature of the Substrate Maintained Low, since the Water Cooling System.

scholarly journals Structural State Scale-Dependent Physical Characteristics and Endurance of Cermet Composite for Cutting Metal

2014 ◽  
Vol 682 ◽  
pp. 405-409
Author(s):  
V.E. Ovcharenko ◽  
A.A. Mohovikov ◽  
Bao Hai Yu ◽  
Yan Hui Zhao
Keyword(s):  
Electron Beam ◽  
Structural State ◽  
Metal Cutting ◽  
Structural Phase ◽  
Cutting Tools ◽  
High Energy ◽  
Pulse Electron Beam ◽  
Al Alloy ◽  
Heating And Cooling ◽  
Subsurface Layers

A structural-phase state developed on the surface of TiC/Ni-Cr-Al alloy cermet under condition of superfast heating and cooling produced by pulse electron beam melting has been presented. The effect of the surface structural state multimodality on the temperature dependencies of friction and endurance of the cermet tool in cutting metal has been investigated. High-energy flux treatment of subsurface layers by electron beam pulses in argon-containing gas discharge plasma serves to improve the endurance of metal cutting tools multiply ( by a factor of 6), to reduce friction on the account of precipitation of secondary 200 nm carbides in binder interlayers. It is possible to improve the cermet tool endurance for cutting metal by a factor of 10-12 by irradiating the cermet in a reactive nitrogen-containing atmosphere with ensuing precipitation of nanosize 50 nm AlN particles in the binder interlayers.

Improving Durability of Cermets for Metal Cutting by Generation of Subsurface Multilevel Structures

2013 ◽  
Vol 379 ◽  
pp. 131-138 ◽  
Author(s):  
V.E. Ovcharenko ◽  
A.A. Mokhovikov ◽  
A.S. Ignatiev
Keyword(s):  
Experimental Data ◽  
Electron Beam ◽  
Structural State ◽  
Electron Beam Melting ◽  
Metal Cutting ◽  
Structural Phase ◽  
Pulse Electron Beam ◽  
Al Alloy ◽  
Pulse Electron ◽  
Heating And Cooling

Experimental data on studying structural-phase states developed in the subsurface of TiC/Ni-Cr-Al alloy cermet under condition of superfast heating and cooling produced by pulse electron beam melting have been presented in this paper. The effect of the surface structural state multimodality on the temperature dependencies of friction and endurance of the cermet tool in cutting metal has been investigated. The effect of structural states on the cermet’s properties consists in improving its endurance for cutting metal by a factor of 20.

THE BEHAVIOR OF GALLIUM CONFINED IN CARBON NANOTUBES DURING HEATING AND COOLING

2008 ◽  
Vol 01 (01) ◽  
pp. 55-58 ◽  
Author(s):  
ZONGWEN LIU ◽  
RONGKUN ZHENG ◽  
KYLE R. RATINAC ◽  
SIMON P. RINGER
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Expansion ◽  
Electron Beam ◽  
Carbon Nanotube ◽  
High Intensity ◽  
Electron Beam Irradiation ◽  
Beam Irradiation ◽  
Orientation Relationships ◽  
Volumetric Expansion ◽  
Heating And Cooling

The thermal expansion of gallium ( Ga ) encapsulated in carbon nanotubes has been studied. It is demonstrated that the volumetric expansion and contraction of the Ga confined in the carbon nanotubes display a linear relationship with temperature. While the level of the tip of the Ga column changes linearly with temperature, it returns to its previous position, without any hysteresis, when reheated or cooled to the original temperature, provided the Ga has not frozen and electron-beam irradiation is minimized. It is shown that electron beam irradiation can cause shrinkage in carbon-nanotube diameter, and that a high-intensity electron beam can also induce the formation of new carbon shells inside the carbon nanotubes. Upon freezing, the solid Ga has two unique orientation relationships with the carbon nanotubes.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

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