scholarly journals Effect of 2024 Al Alloy Insert on the Grain Refinement of a 2024 Al Alloy Prepared via Insert Mold Casting

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1126
Author(s):  
Cheng Zhu ◽  
Zhihao Zhao ◽  
Gaosong Wang ◽  
Qingfeng Zhu ◽  
Shiliang Wang
Keyword(s):  
Immersion Time ◽  
Al Alloy ◽  
Small Particles ◽  
Metallurgical Bonding ◽  
Mold Casting ◽  
Refinement Mechanism ◽  
Temperature Liquid ◽  
Equiaxed Grains ◽  
Liquid Superheat ◽  
Refinement Effect

In this study, an insert mold casting was fabricated by inserting 2024 Al extruded rods into a 2024 Al melt. The molds were kept at a 2024 Al melt for different times. The 2024 Al extruded rods were used to refine the 2024 Al alloy grains because the advantage of this method is that it is contamination free compared with other grain refiners. Moreover, we investigated the macro and microstructure of the ingots. Further, we analyzed the refinement mechanism of the 2024 Al rod on the 2024 Al alloy. Our result showed that when the immersion time of the 2024 Al insert was 0 s, a metallurgical bonding was partly formed between the 2024 Al insert and the 2024 Al alloy mold cast. When the immersion time of the 2024 Al insert increased to 5 s, the 2024 solid insert was dissolved in the liquid; the coarse dendritic grains were replaced by fine equiaxed grains. The refinement mechanism for the insertion of a 2024 Al rod on the 2024 Al alloy was to melt the 2024 Al insert and have it decrease the degree of the liquid superheat, which thus increased the cooling rate and provided a large number of small particles that acted as the nucleus of heterogeneous nucleation. However, these particles were melted gradually in the high-temperature liquid after an increase of immersion time. Thus, the refinement effect of 2024 Al insert on the solidified structure was weakened.

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.

The origin of nuclei and the refinement mechanism for solidified superalloy IN718 under pulsed magnetic field

2009 ◽  
Vol 24 (12) ◽  
pp. 3689-3692 ◽  
Author(s):  
Xiaoping Ma ◽  
Yingju Li ◽  
Yuansheng Yang
Keyword(s):  
Magnetic Field ◽  
Grain Refinement ◽  
Mold Wall ◽  
Mold Temperature ◽  
Experimental Results ◽  
Pulsed Magnetic Field ◽  
Mold Surface ◽  
Refinement Mechanism ◽  
Equiaxed Grains ◽  
Refinement Effect

The grain refinement effect of a pulsed magnetic field on superalloy IN718 was investigated. The experimental results show that fine equiaxed grains are acquired under the pulsed magnetic field. The refinement effect of the pulsed magnetic field is affected by the mold temperature. And the mixed grains are found in the solidified microstructures under the pulsed magnetic field. The origin of nuclei under the pulsed magnetic field is from the mold wall because of the rough mold surface, the undercooling, and the melt vibration, which all contribute to the refinement of solidified grains.

scholarly journals A study of deformation and strain induced in bulk by the oxide layers formation on a Fe-Cr-Al alloy in high-temperature liquid Pb-Bi eutectic

2018 ◽  
Vol 151 ◽  
pp. 301-309 ◽  
Author(s):  
M.P. Popovic ◽  
K. Chen ◽  
H. Shen ◽  
C.V. Stan ◽  
D.L. Olmsted ◽  
...  
Keyword(s):  
High Temperature ◽  
Al Alloy ◽  
Oxide Layers ◽  
Temperature Liquid

The Effect of Mn and Ca Addition on the Microstructure and Mechanical Properties of the Al–Cu–Fe–Si–Zn Based Alloys

2020 ◽  
Vol 20 (7) ◽  
pp. 4307-4311
Author(s):  
Hyo-Sang Yoo ◽  
Yong-Ho Kim ◽  
Seong-Hee Lee ◽  
Hyeon-Taek Son
Keyword(s):  
Mechanical Properties ◽  
Transmission Lines ◽  
Heat Exchangers ◽  
Heat Dissipation ◽  
Al Alloy ◽  
Small Particles ◽  
Microstructure And Mechanical Properties ◽  
Ca Addition ◽  
Electric Materials ◽  
Annealed Copper

High conductivity Al alloys are widely used for electric materials, heat exchangers, and heat dissipation parts such as electric conductors, transmission lines, communication cables, automobile wires and so on. In this study, the effects of Ca and Mn addition on the microstructure and mechanical properties of Al–0.3Cu–0.2Fe–0.15Si–0.15Zn alloys were investigated. The melt was held at 800 °C for 20 minutes and poured into a mold. The cast Al alloy was hot extruded with a rod having a diameter of 12 mm and a reduction ratio of 38:1. Al–0.3Cu–0.2Fe–0.15Si–0.15Zn–0.9Mn–0.4Ca alloy consists of Al, Al–(Fe, Mn)–Si, Al–(Fe, Mn) and Al–(Ca) intermetallic compounds. The formation of the intermetallic compound and this phase was broken in to small particles during extrusion. As the Ca content increased from 0 to 0.4 wt.%, the electrical conductivity of the extruded Al–0.3Cu– 0.2Fe–0.15Si–0.15Zn alloys increased by 57.3, 57.9 and 59.0 %IACS (International annealed copper standard). Al–0.3Cu–0.2Fe–0.15Si–0.15Zn–0.9Mn alloy with element additions of Ca, ultimate tensile strength was decreased from 178.3 to 163.2 and 151.8 MPa. However, the elongation was improved to 18.6, 21.6 and 23.15%.

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.

Microstructure and Properties of Fe-Based Composite Coating by Plasma Jet Surface Metallurgy

2011 ◽  
Vol 179-180 ◽  
pp. 253-256
Author(s):  
Hao Chen ◽  
Jian Gao Yang ◽  
Mi Song Chen
Keyword(s):  
Steel Substrate ◽  
Composite Coatings ◽  
Low Carbon Steel ◽  
Plasma Jet ◽  
Optical Microscope ◽  
Al Alloy ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Metallurgical Bonding

The Fe-based composite coatings were formed by plasma jet surface metallurgy using Fe, C, W, Cr and Al alloy powders on the low carbon steel. The morphology, microstructure, interface structure and the distribution of the in situ particles in the coatings were observed with optical microscope, scanning electron microscope and x-ray diffraction analysis. The results show that metallurgical bonding is obtained between coating and substrate, and the microstructure of coatings is mainly composed of γ-Fe, (Fe,Cr,W,Nb)7C3 and AlFe particles which are synthesized in stiu, are dispersivly distributed in the coatings. The micro-hardness gradually increased from bottom to the top of the coating, the maximum is 986 Hv0.1, about 4 times larger than that of the steel substrate.

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.

Effect of Low-Voltage Pulsed Magnetic Field on Solidified Structure of Superalloy K4169

2013 ◽  
Vol 423-426 ◽  
pp. 725-729
Author(s):  
Xiao Hua Xie ◽  
Quan Zhou ◽  
Cheng Bo Xiao ◽  
Xin Tang
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
Low Voltage ◽  
Pulse Frequency ◽  
Pulse Voltage ◽  
Experimental Results ◽  
Pulsed Magnetic Field ◽  
Equiaxed Grains ◽  
Dendritic Structures ◽  
Refinement Effect

Effects of different pulse voltage and frequency on solidified structure of superalloy K4169 under low-voltage pulsed magnetic field (LVPMF) were investigated in this paper, and the related mechanism was also discussed. The experimental results show that grain of superalloy K4169 can be refined greatly by LVPMF treatment during the course of solidification. Growth of dendrite is restrained and primary grain is changed from large dendrites to smaller equiaxed grains. When the pulse voltage is at 0-280V, grain size of the alloy decreases as pulse voltage increases, and primary dendrites are fractured from well-developed dendrites into fine equiaxed grains and non-dendritic structures. When the pulse frequency is at 0-5Hz, the increase of pulse frequency enhances the refinement effect of LVPMF processing. With the increase of the pulse frequency, grain size of the alloy increases.

Morphology and Tensile Behavior of 2024 Al Alloy Objects Fabricated by Uniform Droplet Spraying Deposition

2012 ◽  
Vol 472-475 ◽  
pp. 787-790
Author(s):  
Peng Yun Wang ◽  
He Jun Li ◽  
Le Hua Qi ◽  
Hai Liang Deng ◽  
Han Song Zuo
Keyword(s):  
Shear Fracture ◽  
Tensile Behavior ◽  
Al Alloy ◽  
Drop On Demand ◽  
Metallurgical Bonding ◽  
Smooth Region ◽  
Molten Droplets ◽  
Rough Region ◽  
Uniform Droplet ◽  
Moving Substrate

A metal rapid prototyping technique, uniform droplet spraying, is utilized to fabricate 2024 Al alloy objects. Molten droplets are generated by drop-on-demand mode and deposited onto a zigzag moving substrate, which produces objects with different side surfaces. The tensile strength of the deposited specimen is 180.5 MPa, with elongation to fracture of ~8.2%. The fracture surface of deposited specimen presents two regions, namely, rough region and smooth region. The smooth region initially cracks under tension load, and the rough region presents many elongated dimples, indicating a ductile shear fracture. This unique tensile behavior could be attributed to weak metallurgical bonding between droplets and the special movement of substrate.

scholarly journals Al-Based Foams as Permanent Cores in Al Castings: Effect of Surface Skin Thickness and Composition on Infiltration and Core-Shell Bonding

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1715
Author(s):  
Sara Ferraris ◽  
Antonio Santostefano ◽  
Antonio Barbato ◽  
Roberto Molina ◽  
Graziano Ubertalli
Keyword(s):  
Skin Thickness ◽  
Al Alloy ◽  
Strength Increase ◽  
Aluminum Foams ◽  
Gravity Casting ◽  
Acoustic Insulation ◽  
Metallurgical Bonding ◽  
Compression Resistance ◽  
Effect Of Surface ◽  
Al Foams

An emerging and still poorly explored application of aluminum foams is their potential use as permanent cores (inserts) in the casting of aluminum alloys. In this context, Al-based foams can introduce a weight reduction, the obtainment of cavities, a strength increase, the ability to absorb impact energy and vibration, acoustic insulation ability, the possibility to simplify the technological processes (no removal/recycling of traditional sand cores), and finally, they can be fully recyclable. Cymat-type Al foams with thin outer skin were used as permanent cores in Al-alloy gravity casting in the present research. Al-foams were characterized in terms of porosity, density, cell wall and skin thickness, surface chemical composition and morphology, and compression resistance. Cast objects with foam inserts were characterized by means of optical microscopy. The preservation of up to 50% of the initial porosity was observed for foam inserts with higher density. Metallurgical bonding between the foam core and the cast metal was observed in some regions.

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