Nano-Precipitated Phase and Evolution of Al-Cu-Mg Alloy Subjected to Rapid Cold Stamping

2019 ◽  
Vol 11 (9) ◽  
pp. 1318-1326
Author(s):  
Caihe Fan ◽  
Ling Ou ◽  
Jianjun Yang ◽  
Xihong Chen
Keyword(s):  
Boundary Diffusion ◽  
Hardness Test ◽  
S Phase ◽  
Mg Alloy ◽  
Fine Grained ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
Three Stages ◽  
Cold Stamping ◽  
Precipitation Phase

High-resolution transmission electron microscopy, energy dispersive spectroscopy, and hardness test were used to study the nano-precipitates and evolution of nano-precipitation of the sprayformed fine-grained Al-Cu-Mg alloy during rapid cold stamping deformation. Results show that the elongated S-phase and the acicular ' phase of the Al-Cu-Mg alloy after three passes of cold stamping of rapid cold-shock deformation undergoes re-dissolution, and a large number of the fine granular balance  phases are precipitated after four passes of rapid cold-stamping deformation. The main mechanism of low-temperature re-dissolution of S' phase and ' phase in Al-Cu-Mg alloy induced by rapid cold stamping deformation is the precipitation phase fracture, grain boundary diffusion, and vacancy diffusion. The change in the hardness of the alloy during rapid cold stamping deformation is affected by the combination of phase-resolving softening, work hardening, and reprecipitation strengthening and increases at three stages. The hardness increases from 55 HB to 125 HB, which is increased by 127%.

Microstructure Evolution and Mechanical Properties of an Al-Cu-Mg Alloy at Elevated Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 148-153
Author(s):  
Min Hao ◽  
Ji Gang Ru ◽  
Ming Liu ◽  
Kun Zhang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Shear Fracture ◽  
S Phase ◽  
Mg Alloy ◽  
Transmission Electron ◽  
Fracture Features ◽  
Scanning Electron

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the microstructure and mechanical behavior of an Al-Cu-Mg alloy after tensile test at 125°C, 150°C, 175°C and 200 °C, respectively. The yield strength and ultimate tensile strength decreased with the increase of temperature, while the elongation increased firstly and then decreased. The S and S′ precipitate after tension at elevated temperatures. When the temperature was higher than 175°C, the precipitate coarsens rapidly. The alloys displayed a shear fracture features at elevated temperature. The larger S′ and S phase coarsened and dropped which forming crack in the grain boundaries and precipitate interfaces, resulting in the decrease of the elongation of the alloy.

Effect of rapid cold stamping on fracture behavior of long strip S′ phase in Al−Cu−Mg alloy

2020 ◽  
Vol 30 (10) ◽  
pp. 2590-2598
Author(s):  
Cai-he FAN ◽  
Ling OU ◽  
Ze-yi HU ◽  
Shu WANG ◽  
Jun-hong WANG
Keyword(s):  
Fracture Behavior ◽  
S Phase ◽  
Mg Alloy ◽  
Cold Stamping

Niobium-Alloyed Steel Treated by Quenching-Partitioning-Tempering

2014 ◽  
Vol 528 ◽  
pp. 149-152
Author(s):  
Hua Zheng ◽  
Kai Ming Wu ◽  
S.F. Sun ◽  
G.W. Hu
Keyword(s):  
Hardness Test ◽  
Optical Microscope ◽  
Medium Carbon Steel ◽  
Test Results ◽  
X Ray Diffraction ◽  
Medium Carbon ◽  
X Ray ◽  
Fine Grained ◽  
Recent Interest ◽  
Transmission Electron

Given the strong recent interest in quenching-partitioning-tempering processed steels, the Niobium-alloyed medium carbon steel was investigated here. The microstructural observations and hardness were analyzed by optical microscope, transmission electron microscope, X-ray diffraction and hardness test. Results show that when quenched at 210°C and partitioned at 450°C, the quenching partitioning-tempering process leads to ultra fine-grained microstructures of martensite, retained austenite and carbides. And the microstructure and hardness changed differently with the increase of partitioned time.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

scholarly journals Characterization of Precipitation in 7055 Aluminum Alloy by Laser Ultrasonics

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 275
Author(s):  
Zhenge Zhu ◽  
Hao Peng ◽  
Yacheng Xu ◽  
Xueyong Song ◽  
Jinrong Zuo ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Laser Ultrasonics ◽  
Precipitate Size ◽  
Destructive Testing ◽  
Laser Ultrasonic ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
7055 Aluminum Alloy ◽  
The Time Domain

After different rolling conditions, four 7055 aluminum alloy samples with different precipitation sizes were measured by scanning electron microscope, transmission electron microscope and laser ultrasonic. The attenuation coefficients of ultrasound measured by laser ultrasonic were calculated in the time domain, frequency domain and wavelet denoising, respectively. The relationship between the precipitate size and attenuation coefficient was established. The results show that the attenuation of the ultrasonic wave is related to the size of the precipitated phase; this provides a new method for rapid non-destructive testing of the precipitation of aluminum alloys.

Direct Cladding from Molten Metals of Aluminum and Magnesium Alloys Using a Tandem Horizontal Twin Roll Caster

2015 ◽  
Vol 772 ◽  
pp. 250-256 ◽  
Author(s):  
Hideto Harada ◽  
Shin Ichi Nishida ◽  
Mayumi Suzuki ◽  
Hisaki Watari ◽  
T. Haga
Keyword(s):  
Surface Condition ◽  
Hardness Test ◽  
Al Alloys ◽  
Mg Alloy ◽  
Al Alloy ◽  
Molten Metals ◽  
Electron Probe Micro Analyzer ◽  
Twin Roll Caster ◽  
Aluminum And Magnesium Alloys ◽  
Twin Roll

This paper describes direct cladding of magnesium (Mg) and aluminum (Al) alloys using a tandem horizontal twin roll caster that has three pairs of upper and lower rolls. Manufacturing conditions that are appropriate for fabricating Al/Mg and Al/Mg/Al cladded material were investigated. The surface condition of the cladded cast strip was examined. An electron probe micro analyzer was used to observe the interface between Al alloy and Mg alloy. The thickness of the mixed layer of Al and Mg alloy was 15μm, and how the materials were connected was clarified. Microscopic observation and backscattered electron analysis were used to investigate the cladding mechanisms of the Al and Mg alloy layers. Average hardness was determined using the Vickers hardness test at the Al layer and at the diffused layer between Mg and Al alloys. Cladding of Al/Mg alloy and A/Mg/Al alloy was possible using a tandem twin-roll caster. In addition, Al3Mg2 and Al12Mg17 phase precipitation at the interface of the Al and Mg alloys was confirmed during direct cladding from molten metals.

Investigation of low- and high-resistance Ni–Ge–Au ohmic contacts to n+ GaAs using electron microbeam and surface analytical techniques

1996 ◽  
Vol 11 (5) ◽  
pp. 1244-1254 ◽  
Author(s):  
Nancy E. Lumpkin ◽  
Gregory R. Lumpkin ◽  
K. S. A. Butcher
Keyword(s):  
Electron Microscopy ◽  
Ohmic Contacts ◽  
Analytical Electron Microscopy ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Two Phase ◽  
Low Resistance ◽  
Fine Grained ◽  
Multiphase Microstructure ◽  
Transmission Electron

A process for the formation of low-resistance Ni–Ge–Au ohmic contacts to n+ GaAs has been refined using multivariable screening and response surface experiments. Samples from the refined, low-resistance process (which measure 0.05 ± 0.02 Ω · mm) and the unrefined, higher resistance process (0.17 ± 0.02 Ω · mm) were characterized using analytical electron microscopy (AEM), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and x-ray photoemission spectroscopy (XPS) depth profiling methods. This approach was used to identify microstructural differences and compare them with electrical resistance measurements. Analytical results of the unrefined ohmic process sample reveal a heterogeneous, multiphase microstructure with a rough alloy-GaAs interface. The sample from the refined ohmic process exhibits an alloy which is homogeneous, smooth, and has a fine-grained microstructure with two uniformly distributed phases. XPS analysis for the refined ohmic process sample indicates that the Ge content is relatively depleted in the alloy (relative to the deposited Ge amount) and enriched in the GaAs. This is not evidenced in the unrefined ohmic process sample. Our data lead us to conclude that a smooth, uniform, two-phase microstructure, coupled with a shift in Ge content from the post-alloy metal to the GaAs, is important in forming low-resistance ohmic contacts.

Evolutions of Microstructure for Multilayered Al-Mg Alloy Composites by Accumulation Roll Bonding (ARB) Process

2011 ◽  
Vol 411 ◽  
pp. 527-531
Author(s):  
Bing Zhang ◽  
Zhong Wei Chen ◽  
Shou Qian Yuan ◽  
Tian Li Zhao
Keyword(s):  
Multilayer Structure ◽  
Optical Microscope ◽  
Alloy Layer ◽  
Mg Alloy ◽  
Micro Hardness ◽  
Roll Bonding ◽  
Fine Grained ◽  
Hardness Tester ◽  
Average Grain Size ◽  
Evolution Of Microstructure

In this paper, accumulative roll bonding (ARB) has been used to prepare the Al/Mg alloy multilayer structure composite materials with 1060Al sheet and MB2 sheet. The evolution of microstructure of the cladding materials during ARB processes was observed by optical microscope, scanning electron microscopy, and micro-hardness was measured by micro-hardness tester. The results show that a multilayer structure material of Al/Mg alloy with excellent bonding characteristics and fine grained microstructure was prepared by ARB processes. With the ARB cycles increasing, Mg alloy layer in multilayer composite material was necked and fractured, and the hardness of the Al and Mg alloy was increased. Average grain size was less than 1μm after ARB4 cycles.

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