scholarly journals The Effects of a Trace Amount of Manganese and the Homogenization on the Recrystallization of Al–7Mg–0.15Ti Alloys

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 168
Author(s):  
Yang-Chun Chiu ◽  
Tse-An Pan ◽  
Guan-Ming Chen ◽  
Xin-Cheng Jiang ◽  
Hui-Yun Bor ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Grain Growth ◽  
Aluminum Matrix ◽  
Normal Growth ◽  
Tensile Tests ◽  
Dispersion Strengthening ◽  
Rockwell Hardness ◽  
Homogenization Treatment ◽  
Homogenization Process ◽  
Transmission Electron

The aim of this study is to explore the effects of Manganese addition and homogenization treatment on the microstructures and mechanical properties of the Al–7Mg–0.15Ti (B535.0) alloy. The optical microscopy, electrical conductivity measurements, transmission electron microscopy, scanning electron microscopy (SEM + EBSD), as well as Rockwell hardness and tensile tests, were exploited for this purpose. The main objectives are to refine the grain size, inhibit grain growth in the annealed state, and enhance the mechanical strength of the alloy. The results show that the addition of manganese to the Al–7Mg–0.15Ti alloys refined the as-cast and recrystallized grains of the alloys. During the homogenization process, Al4Mn high-temperature stable dispersoids were precipitated in the aluminum matrix. After annealing, the Al4Mn particles blocked the movement of grain boundaries during the growth of the recrystallized grains and inhibited grain growth. Consequently, the annealed alloys showed grain refinement and dispersion strengthening. The Al4Mn dispersoids of the alloys with manganese added were smaller and denser after a two-stage homogenization process compared to those that underwent a one-stage homogenization process. By contrast, for the alloys without the addition of manganese, the recrystallized grains showed normal growth after annealing, and different homogenization processes had no significantly different effects.

The Effect of Grain Size on Superplastic Deformation of Ti-6Al-4V Alloy

2007 ◽  
Vol 551-552 ◽  
pp. 387-392 ◽  
Author(s):  
Wen Juan Zhao ◽  
Hua Ding ◽  
D. Song ◽  
F.R. Cao ◽  
Hong Liang Hou
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Superplastic Deformation ◽  
Initial Strain Rate ◽  
Deformation Mode ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Coarse Grained ◽  
Transmission Electron ◽  
Grain Growth Model

In this study, superplastic tensile tests were carried out for Ti-6Al-4V alloy using different initial grain sizes (2.6 μm, 6.5μm and 16.2 μm) at a temperature of 920°C with an initial strain rate of 1×10-3 s-1. To get an insight into the effect of grain size on the superplastic deformation mechanisms, the microstructures of deformed alloy were investigated by using an optical microscope and transmission electron microscope (TEM). The results indicate that there is dramatic difference in the superplastic deformation mode of fine and coarse grained Ti-6Al-4V alloy. Meanwhile, grain growth induced by superplastic deformation has also been clearly observed during deformation process, and the grain growth model including the static and strain induced part during superplastic deformation was utilized to analyze the data of Ti-6Al-4V alloy.

Effects of Surface Energy on the Microstructures of Thin Sb Films

1990 ◽  
Vol 202 ◽  
Author(s):  
L. H. Chou ◽  
M. C. Kuo
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Grain Growth ◽  
Grain Orientation ◽  
Thermal Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Transmission Electron ◽  
Diffraction Peaks

ABSTRACTThin Sb films have been prepared on glass substrates by rapid thermal evaporation. Films with thicknesses varied from 260 Å to 1300Å were used for the study. X-ray diffraction data showed that for films deposited at room substrate temperature, an almost random grain orientation was observed for films of 1300 Å thick and a tendency for preferred grain orientation was observed as films got thinner. For films of 260 Å thick, only two x-ray diffraction peaks--(003) and (006) were observed. After thermal annealing, secondary grains grew to show preferred orientation in all the films. This phenomenon was explained by surface-energy-driven secondary grain growth. This paper reports the effects of annealing time and film thickness on the secondary grain growth and the evolution of thin Sb film microstmctures. Transmission electron microscopy (TEM) and x-ray diffraction were used to characterize the films.

Homogenization Treatment to Optimize the Microstructures of the Al-3.5Cu-1.5Li Alloy and Analysis of Al3Zr Precipitates

2018 ◽  
Vol 921 ◽  
pp. 195-201 ◽  
Author(s):  
Jin Jun Xu ◽  
Mang Jiang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectrometry ◽  
Single Step ◽  
Experimental Alloy ◽  
Composition Distribution ◽  
Double Step ◽  
Homogenization Treatment ◽  
Transmission Electron ◽  
Scanning Electron

The microstructure evolution and composition distribution of the cast Al-3.5Cu-1.5Li-0.11Zr alloy during single-step and double-step homogenization were studied with the help of the optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and transmission electron microscopy (TEM) methods. The results show that severe dendrite segregation exists in the experimental alloy. Six different homogenization treatments, conventional one-stage homogenization and double-stage homogenization are carried out, and the best homogenization treatment of the experimental alloys was achieved. Moreover, the precipitation of Al3Zr particles was significantly different after two kinds of homogenization in the experimental alloy. Compared with the single-stage homogenization, a finer particle size and distribution more diffuse of Al3Zr particles can be obtained in the double-stage homogenization treatment.

scholarly journals Study of the Microstructure and Crack Evolution Behavior of Al-5Fe-1.5Er Alloy

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 172 ◽  
Author(s):  
Ming Li ◽  
Zhiming Shi ◽  
Xiufeng Wu ◽  
Huhe Wang ◽  
Yubao Liu
Keyword(s):  
Electron Microscopy ◽  
Crack Initiation ◽  
Tensile Tests ◽  
Eutectic Structure ◽  
Interface Structure ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Evolution Behavior

In this work, the microstructure of Al-5Fe-1.5Er alloy was characterized and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) techniques. The effect of microstructure on the behavior of crack initiation and propagation was investigated using in situ tensile testing. The results showed that when 1.5 wt.% Er was added in the Al-5Fe alloy, the microstructure consisted of α-Al matrix, Al3Fe, Al4Er, and Al3Fe + Al4Er eutectic phases. The twin structure of Al3Fe phase was observed, and the twin plane was {001}. Moreover, a continuous concave and convex interface structure of Al4Er was observed. Furthermore, Al3Fe was in the form of a sheet with a clear gap inside. In situ tensile tests of the alloy at room temperature showed that the crack initiation mainly occurred in the Al3Fe phase, and that the crack propagation modes included intergranular and trans-granular expansions. The crack trans-granular expansion was due to the strong binding between Al4Er phases and surrounding organization, whereas the continuous concave and convex interface structure of Al4Er provided a significant meshing effect on the matrix and the eutectic structure.

scholarly journals Effect of Two-Stage Homogenization Heat Treatment on Microstructure and Mechanical Properties of AA2060 Alloy

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Chaoyang Chaoyang ◽  
Guangjie Guangjie ◽  
Lingfei Lingfei ◽  
Fei Fei ◽  
Lin Lin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Cast Alloy ◽  
Hardness Test ◽  
Test Methods ◽  
Al Alloy ◽  
Two Stage ◽  
Homogenization Treatment ◽  
Transmission Electron ◽  
The Matrix

The microstructure evolution of AA2060 Al alloy containing Li during two-stage homogenization treatment was investigated by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), mechanical properties and Vickers micro-hardness test methods. The results demonstrate that severe precipitation of θ(Al2Cu) and S(Al2CuMg) phase existed in the as-cast alloy, especially in the center position. Cu elements were concentrated at grain boundary and gradually decreased from the boundary to the interior. Numerous eutectic phases of θ(Al2Cu) and S (Al2CuMg) containing Zn and Ag elements were segregated at grain boundaries. The overheating temperature of the as-cast alloy is 497 °C. After two-stage homogenization treatment, the θ(Al2Cu) and S (Al2CuMg) in the surface, middle and center positions were completely dissolved into the matrix, thus achieved uniform homogenization effect. Moreover, water cooling could prevent the precipitation after homogenization, which provided good performance of the studied alloy. The optimum two-stage homogenization treatment of AA2060 alloy was 460 °C/4 h + 490 °C/2 4 h. The homogenization kinetic analysis was discussed as well.

Microstructural Evolution of a Commercial 0.04%C Steel During Batch Annealing

2006 ◽  
Vol 509 ◽  
pp. 17-24
Author(s):  
J.C. Millán ◽  
A.L. Rivas ◽  
Jose María Cabrera ◽  
Sonia Camero ◽  
Leo Kestens
Keyword(s):  
Grain Growth ◽  
Microstructural Evolution ◽  
Plastic Anisotropy ◽  
Tensile Tests ◽  
Grain Structure ◽  
Heating Process ◽  
Heating Rates ◽  
Hold Period ◽  
Transmission Electron ◽  
Batch Annealing

The effect of heating rate and annealing time on the microstructure and texture of a commercial 0.04 %C steel, cold rolled up to 80 %, is studied. Samples have been isothermally annealed at various heating rates (12 °C/h, 20 °C/h, 40 °C/h and 650 °C/min) and then soaked at 700 °C for 15 hours. The microstructural evolution of the samples during the heating process and hold period has been followed by optical microscopy, scanning and transmission electron microscopy. The electron back-scattered diffraction technique is used to reveal the texture of the samples. Tensile tests and hardness measurements are correlated with the microstructural features. Results show that (a) recrystallization occurs between 600 and 650 °C; (b) a “pancake” structure develops during recrystallization at low heating rates without appreciable grain growth; (c) samples heated at 650 °C/min exhibit an equiaxed grain structure and significant grain growth; (d) only at low heating rates the material develops a strong {111}<uvw> recrystallization texture, in ccordance with the high plastic anisotropy found by mechanical testing.

Grain growth in ultrathin films of CoPt and FePt

1999 ◽  
Vol 14 (8) ◽  
pp. 3263-3270 ◽  
Author(s):  
R. A. Ristau ◽  
K. Barmak ◽  
K. R. Coffey ◽  
J. K. Howard
Keyword(s):  
Electron Microscopy ◽  
Grain Growth ◽  
Ultrathin Films ◽  
Growth Stage ◽  
Fiber Texture ◽  
Digital Analysis ◽  
Bright Field ◽  
Transmission Electron ◽  
Grain Growth Kinetics ◽  
Two Stages

The microstructure of sputtered 10-nm thin films of equiatomic binary alloys of CoPt and FePt was characterized using transmission electron microscopy (TEM). Grain growth kinetics was examined using manual and digital analysis of bright-field TEM images and was seen to take two stages during annealing in these films. A rapid growth stage concurrent with the formation of a [111] fiber texture was observed to occur within the first 5–10 min of annealing, followed by a much slower growth stage after the fiber texturing was well advanced. Differences in grain growth rate and ultimate grain size were also observed to depend on heating rate.

scholarly journals Microstructure and Mechanical Properties of Carbides Reinforced Nickel Matrix Alloy Prepared by Selective Laser Melting

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4792
Author(s):  
Tian Xia ◽  
Rui Wang ◽  
Zhongnan Bi ◽  
Rui Wang ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Selective Laser Melting ◽  
High Efficiency ◽  
Matrix Alloy ◽  
Tensile Tests ◽  
Laser Melting ◽  
Haynes 230 ◽  
Transmission Electron ◽  
Room Temperature Yield Strength ◽  
The Matrix

Selective laser melting was used to prepare the ceramic particles reinforced nickel alloy owing to its high designability, high working flexibility and high efficiency. In this paper, a carbides particles reinforced Haynes 230 alloy was prepared using SLM technology to further strengthen the alloy. Microstructures of the carbide particles reinforced Haynes 230 alloy were investigated using electron microscopy (SEM), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM). Meanwhile, the tensile tests were carried out to determine the strengths of the composite. The results show that the microstructure of the composite consisted of uniformly distributed M23C6 and M6C type carbides and the strengths of the alloy were higher than the matrix alloy Haynes 230. The increased strengths of the carbide reinforced Haynes 230 alloy (room temperature yield strength 113 MPa increased, ~ 33.2%) can be attributed to the synergy strengthening including refined grain strengthening, Orowan strengthening and dislocation strengthening.

Epitaxially induced secondary grain growth in Ti:LiNbO3 optical waveguides

1989 ◽  
Vol 47 ◽  
pp. 424-425
Author(s):  
M. A. McCoy
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Transmission Electron Microscopy ◽  
Refractive Index ◽  
Lithium Niobate ◽  
Grain Growth ◽  
Optical Waveguides ◽  
Waveguide Devices ◽  
Transmission Electron ◽  
Electro Optic

Lithium niobate (LiNbO3) is one of the most promising materials for use in hybrid optical waveguide devices because of its high electro-optic coefficient and its availability as large single crystals. Optical waveguides in LiNbO3 are most commonly made by Ti indiffusion in which strips of Ti metal (between 10 and 100 nm thick) are deposited on a single crystal LiNbO3 substrate. The device is then heated to temperatures around 1000°C typically for 6 hours. During this time, the Ti diffuses into the LiNbO3 to form a Ti-rich LiNbO3 solid solution. This solid solution has a higher refractive index than the substrate and forms the waveguide region. Factors controlling the indiffusion process, however, are not very well understood and very little is known about the microstructural changes which occur during Ti indiffusion. In this study, the microstructure of Ti:LiNbO3 optical waveguides was examined as a function of time and temperature using transmission electron microscopy (TEM).

Polycrystalline Silicon Layers with Enhanced Thermal Stability

2011 ◽  
Vol 178-179 ◽  
pp. 385-391
Author(s):  
David Lysáček ◽  
Jan Šik ◽  
Petr Bábor
Keyword(s):  
Electron Microscopy ◽  
Grain Growth ◽  
Polycrystalline Silicon ◽  
Silicon Oxide ◽  
Silicon Layer ◽  
Multilayer System ◽  
Oxide Layers ◽  
Transmission Electron ◽  
Subsequent Loss

We report on a new method of external gettering in silicon substrate for semiconductor applications. The proposed method is based on the deposition of a multilayer system formed by introducing a number of thin buried silicon oxide layers into the thick polycrystalline silicon layer deposited on the wafer backside. Oxide films of a few nanometer thicknesses significantly retard both the grain growth and subsequent loss of the gettering capability of the polycrystalline silicon layer during high temperature annealing. The mechanisms of the grain growth and the influence of the embedded oxide layers on the gettering function in the multilayer system are discussed. We used scanning electron microscopy and transmission electron microscopy for the characterization of the multilayer system, and intentional contamination for demonstration of the gettering properties.

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