Effect of Combined Electromagnetic Fields on the Structure of a HDC Casting 2024 Al Alloy Ingot

2013 ◽  
Vol 765 ◽  
pp. 82-86 ◽  
Author(s):  
Qing Feng Zhu ◽  
Zhi Hao Zhao ◽  
Yu Bo Zuo ◽  
Lei Li ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Fields ◽  
Horizontal Direction ◽  
Bottom Surface ◽  
Al Alloy ◽  
Cast Ingot ◽  
Alloy Ingot ◽  
Ingot Structure ◽  
Equiaxed Grains

2024 Al alloy ingot with diameter of 100 mm is produced by conventional and combined electromagnetic fields (CEMF) horizontal direction chill (HDC) casting processes. The effect of CEMF on the ingot structure is investigated. The results show that the CEMF is effective in changing the inner structure of the 2024 HDC cast ingot. In the conventional HDC ingot, feathery grains mainly distribute over the majority of the area of the ingot, and coarse equiaxed grains mixed with coarse floating grains distribute in a crescent-shaped area near the bottom surface. With the application of the CEMF, the majority of the feathery grains transform to fine equiaxed grains, and the mixture of feathery and fine grains only exist in the area near the upper surface. In addition, the coarse floating grains completely disappeared in the ingot with the application of CEMF.

Effect of Combined Electromagnetic Fields on the As-Casting Structure and Mechanical Property of HDC Casting 7075 Al Alloy Ingot

PRICM ◽  
2013 ◽  
pp. 1009-1016
Author(s):  
Qingfeng Zhu ◽  
Zhihao Zhao ◽  
Yubo Zuo ◽  
Lei Li ◽  
Xiangjie Wang ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Electromagnetic Fields ◽  
Al Alloy ◽  
Alloy Ingot ◽  
7075 Al Alloy

A Novel Method to Fabricate Silver Chloride Films

2011 ◽  
Vol 117-119 ◽  
pp. 652-655
Author(s):  
Hui Chung Hsueh ◽  
Zue Chin Chang ◽  
Chang Ching You ◽  
C. B. Lin
Keyword(s):  
Aqueous Solution ◽  
Sodium Chloride ◽  
Cross Section ◽  
Silver Chloride ◽  
Bottom Surface ◽  
Heterogeneous Precipitation ◽  
Columnar Grains ◽  
Novel Method ◽  
Equiaxed Grains ◽  
Chloride Film

Abstract: This investigation develops a novel method for fabricating silver chloride films by the heterogeneous precipitation of sodium chloride from aqueous solution and supersaturated solid-state silver nitrate out of aqueous solution. The morphology of the bottom surface of the silver chloride film thus obtained comprises numerous porous stick structures. The top surface comprises equiaxed grains, and columnar grains are observed in the cross-section.

scholarly journals The Interaction between Grains during Columnar-to-Equiaxed Transition in Laser Welding: A Phase-Field Study

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1647
Author(s):  
Lingda Xiong ◽  
Chunming Wang ◽  
Zhimin Wang ◽  
Ping Jiang
Keyword(s):  
Laser Welding ◽  
Phase Field ◽  
Numerical Results ◽  
Model Alloy ◽  
Columnar Dendrite ◽  
Nucleation Density ◽  
Al Alloy ◽  
Nucleation Undercooling ◽  
Columnar To Equiaxed Transition ◽  
Equiaxed Grains

A phase-field model was applied to study CET (columnar-to-equiaxed transition) during laser welding of an Al-Cu model alloy. A parametric study was performed to investigate the effects of nucleation undercooling for the equiaxed grains, nucleation density and location of the first nucleation seed ahead of the columnar front on the microstructure of the fusion zone. The numerical results indicated that nucleation undercooling significantly influenced the occurrence and the time of CET. Nucleation density affected the occurrence of CET and the size of equiaxed grains. The dendrite growth behavior was analyzed to reveal the mechanism of the CET. The interactions between different grains were studied. Once the seeds ahead of the columnar dendrites nucleated and grew, the columnar dendrite tip velocity began to fluctuate around a value. It did not decrease until the columnar dendrite got rather close to the equiaxed grains. The undercooling and solute segregation profile evolutions of the columnar dendrite tip with the CET and without the CET had no significant difference before the CET occurred. Mechanical blocking was the major blocking mechanism for the CET. The equiaxed grains formed first were larger than the equiaxed grains formed later due to the decreasing of undercooling. The size of equiaxed grain decreased from fusion line to center line. The numerical results were basically consistent with the experimental results obtained by laser welding of a 2A12 Al-alloy.

Influence of ECAP Routes on the Microstructure and Mechanical Properties of Hot Extruded 3003 Al Alloy

2007 ◽  
Vol 124-126 ◽  
pp. 1397-1400 ◽  
Author(s):  
Byoung Soo Lee ◽  
Hoon Cho
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Hot Extrusion ◽  
High Strength ◽  
Al Alloy ◽  
Deformation Structure ◽  
Ecap Processing ◽  
Fine Grained ◽  
Strain Process ◽  
Equiaxed Grains

The microstructures and mechanical properties of unidirectional deformation structured Al alloy during ECAP with various deformation routes were investigated. In order to fabricate unidirectional deformation structure for Al alloy, hot extrusion was carried out. It was found that the deformation route A in ECAP routes is the dominant route for the grain refinement and strengthening. In deformation route A, the high strength ultra-fine grained Al alloy with a grain size of ~ 200 nm was obtained due to the accumulation of consecutive strain process. In contrast, the strength of ECAP’ed Al alloy produced via deformation route C was greatly increased after one pass because the grains were strained and cancelled each pass. By contrast, the equiaxed grains were obtained in deformation route BC because the sample was rotated 90 O in the same sense in each pass. The deformation route BC was superior to the deformation route C because the deformation route BC was more favorable than the deformation route C in the accumulation of consecutive strain. It is also found that unidirectional deformation structured Al alloy via hot extrusion shows similar grain refinement tendency with equiaxed structured Al alloy during ECAP processing.

Process of Equiaxed Grains of RE-Al Alloy under Slope Vibration

2010 ◽  
Vol 146-147 ◽  
pp. 349-352
Author(s):  
Shi Kun Xie ◽  
Rong Xi Yi ◽  
Shu Qin Li ◽  
Xiao Liang Pan ◽  
Xiao Qiu Zheng
Keyword(s):  
Isothermal Holding ◽  
Casting Process ◽  
Al Alloy ◽  
Dendritic Microstructure ◽  
Holding Period ◽  
Mold Casting ◽  
A New Technique ◽  
Semi Solid ◽  
Equiaxed Grains ◽  
Vibration Casting

A new technique using slope vibration casting process during heating and isothermal holding period to prepare Al-7Si-2RE alloy has been studied. The small, near-spherical and non-dendritic microstructure with the semi-solid processing requirements has been obtained. Experiments show that the cooling method, pouring process and the convection of melt caused by slope vibration had significant effects on the formation of near-spherical primary gains. The water-cooled copper mold casting with slope vibration at the temperature near liquidus can obtain Al-7Si-2RE alloy with small homogeneous equiaxed grains, the average grain diameter is 48.3μm, and the average grain roundness is 1.92.

Microstructure of the Dissimilar Materials TIG Welding Joint of Mg-8Li Alloy/Al Alloy

2012 ◽  
Vol 557-559 ◽  
pp. 1358-1363
Author(s):  
Dong Song Yin ◽  
Lu Cai Wang ◽  
Bin Jiang ◽  
Mi Lin Zhang ◽  
Li He Mao ◽  
...  
Keyword(s):  
Base Metal ◽  
Reaction Layer ◽  
Arc Welding ◽  
Weld Zone ◽  
Dissimilar Materials ◽  
Optical Microscope ◽  
Al Alloy ◽  
Alloy Base ◽  
Weld Area ◽  
Equiaxed Grains

Microstructure of electromagnetic pulse tungstic electrode argon arc welding (EMP-TIG) welded Mg/Al dissimilar metal joint is studyed using optical microscope, scanning electron microscope, and X-ray diffraction. The results indicate that gas tungsten arc welding can provide Mg/Al joint with excellent microstructure and performance. The welding region is composed of Mg3Al2 phase, α(Mg), β(Li), and MgAl. The weld zone and the Al alloy base materials are well combined. There are massive MgAl phase dendrites in the weld area, which cause the significantly increase of hardness at weld zone. Near the Mg-8Li alloy base metal side of the weld zone, there exists a layer of 100~ 200μm equiaxed region. About 1μm Mg3Al2 reaction layer is distributed between Mg-8Li alloy base metal and the equiaxed grains. This reaction layer and the Mg-8Li alloy base metal, as well as the weld zone of equiaxed grains, have a good combination.

Superplasticity in Nb3Al/Nb In Situ Composites

1999 ◽  
Vol 601 ◽  
Author(s):  
S. Hanada ◽  
W. Fang
Keyword(s):  
Superplastic Deformation ◽  
Grain Boundary Sliding ◽  
Al Alloy ◽  
Two Phase ◽  
Dislocation Glide ◽  
In Situ Composite ◽  
Al Content ◽  
Boundary Sliding ◽  
Equiaxed Grains

AbstractMicrostructures of a binary Nb-15.8at%Al alloy ingot were controlled by isothermal forging and heat treatment to produce equiaxed, fine grains of Nb3Al and Nb solid solution (Nb33). Nb3Al/Nb33 two phase alloy (in-situ composite) is found to exhibit superplasticity especially when one of the constituent phases, Nb33, is supersaturated. During superplastic deformation Nb33 transforms to Nb3Al, and Al content in Nb33 decreases. After superplastic deformation the microstructure consisting of equiaxed grains is left unchanged, although a slight grain growth is observed. It is suggested that stress induced by grain boundary sliding is effectively accommodated through dislocation glide and climb in the soft Nb33

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