Investigation of Square Wave Pulsed Currents on Solidification Behavior of Al-Cu Alloys

2010 ◽  
Vol 160-162 ◽  
pp. 1767-1771
Author(s):  
Xiao Tian Yang ◽  
Xia Li ◽  
Wen Sheng Li
Keyword(s):  
Temperature Region ◽  
Solidification Process ◽  
Solidification Structure ◽  
Recording Instrument ◽  
Metal Solidification ◽  
Square Wave ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Temperature Recording ◽  
Equiaxed Grains

Al-(4-5)%Cu alloy was served as experiment material，the effect of pulsed currents on the solidification structure was investigated. During the solidification process of Al-Cu alloys, pulsed currents was added into the melted alloy in the crucible .The change of temperature curve and microstructure about the alloy was investigated in such conditions by temperature-recording instrument and optical microscope.The results showed that pulsed currents can shorten the temperature region of crystallization and refine the grains of the alloy,which crush the dendrite and make the solidification structure non-dendrite, presenting columnar and equiaxed grains which are distributed evenly and whose space between crystals are reduced. This investigation firstly started to study the relations between the temperature region of crystallization and organization structure of solidification. Finally, the mechanism of metal solidification affected by square wave pulsed currents was discussed.

scholarly journals Effect of Nb addition on the solidification structure of Fe–Mn–C–Al twin-induced plasticity steel

2020 ◽  
Vol 39 (1) ◽  
pp. 599-607
Author(s):  
Wen-Hui Du ◽  
Chang-Rong Li ◽  
Chang-Ling Zhuang
Keyword(s):  
Crystallization Rate ◽  
Solidification Process ◽  
Growth Direction ◽  
Solidification Structure ◽  
Second Phase ◽  
Second Phase Particles ◽  
Columnar Grains ◽  
Equiaxed Grains ◽  
Mn Steel

AbstractThe solidification microstructure of an Fe–Mn–C–Al high-Mn steel with added Nb was studied by optical microscopy and scanning electron microscopy. The results showed that the size of the columnar and equiaxed grains in the solidified structure of the high-Mn steel without added Nb was large. When Nb was added, the size of the equiaxed and columnar grains in the solidification structure of the high-Mn steel decreased. The twin-induced plasticity in the high-Mn steel with added Nb clearly refined the grain size of the solidified structure and simultaneously increased the equiaxed crystallization rate. The high-melting-point second-phase particles increased the heterogeneous nucleation rate, which was beneficial for grain refinement. A large amount of Nb precipitates from the solidification process increased the equiaxed crystallization rate of the solidified microstructure. The increased crystallization rate affected the growth direction of the columnar and equiaxed grains during solidification and indirectly decreased the probability of crack formation, which improved the quality of the twin-induced plastic steel.

Grain refinement mechanism of rapidly solidified nickel alloys

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hongfu Wang ◽  
Hongen An ◽  
Shaopei Yang
Keyword(s):  
Grain Refinement ◽  
Nickel Alloys ◽  
Boundary Migration ◽  
Solidification Structure ◽  
Grain Boundary Migration ◽  
High Undercooling ◽  
Cu Alloys ◽  
Refinement Mechanism ◽  
Rapidly Solidified ◽  
Equiaxed Grains

Abstract The solidification microstructure evolution of Ni-25 at.% Cu alloys under different undercooling degrees were studied by the cladding method and cyclic superheating method. Two grain refinement phenomena were observed in the obtained undercooling. In the low undercooling condition, dendrite remelting is the main reason for grain refinement in the recalescence process, while in the high undercooling condition, the stress accumulated in the recalescence process leads to recrystallization in the later stage of recalescence. Under the condition of high undercooling, the solidification structure is composed of complete equiaxed grains with relatively uniform grain size, which indicates that grain boundary migration occurs during grain growth.

Simulation of Microstructures in Solidification of Continuous Casting Aluminum Alloy Thin Strip

2011 ◽  
Vol 399-401 ◽  
pp. 1750-1754
Author(s):  
Shou Dong Chen ◽  
Jing Chao Chen ◽  
Lian Hao Lv
Keyword(s):  
Aluminum Alloy ◽  
Continuous Casting ◽  
Solidification Process ◽  
Solidification Structure ◽  
Thin Strip ◽  
Metal Solidification ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum ◽  
Twin Roll ◽  
Kinetics Of

Based on the research on the solidification of twin-roll continuous casting aluminum alloy thin strip, the analytical model of heterogeneous nucleation, the growth kinetics of tip (KGT) of twin-roll continuous casting aluminum alloy thin strip solidification are established by means of the principle of metal solidification, meantime based on the cellular automaton, the emulational model of twin-roll continuous casting aluminum alloy thin strip solidification is established. The foundation for the emulational simulation of twin-roll continuous casting thin strip solidification structure is laid. Meanwhile has confirmed the mathematical simulation feasibility by using the solidification process of twin-roll continuous casting aluminum alloy Thin Strip.

Thermal Parameters, Tertiary Dendritic Growth and Microhardness of Directionally Solidified Al-3wt%Cu Alloy

2016 ◽  
Vol 869 ◽  
pp. 452-457 ◽  
Author(s):  
André Santos Barros ◽  
Maria Adrina Paixão de Souza da Silva ◽  
Otávio Fernandes Lima da Rocha ◽  
Antonio Luciano Seabra Moreira
Keyword(s):  
Growth Rate ◽  
Directional Solidification ◽  
Cooling Rate ◽  
Dendritic Growth ◽  
Solidification Process ◽  
Flow Conditions ◽  
Directionally Solidified ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Transient Heat Flow

The main purpose of this paper is to evaluate both tertiary dendritic arm growth and microhardness of Al-3wt%Cu alloy during horizontal directional solidification under transient heat flow conditions. Experimental thermal profiles recorded during solidification process allowed to determine growth rate and cooling rate values which are associated with both tertiary dendritic arm spacings and microhardness. The results show that initial tertiary branches growth only occurs when a cooling rate value of 1.14 K/s is reached. Variation of tertiary spacings is expressed as-1.1 and-0.55 power law functions of growth rate and cooling rate, respectively. A comparative analysis with other studies published in the literature that analyze tertiary dendritic growth of Al-Cu alloys considering transient directional solidification is carried out. Dependence of microhardness on dendritic arrangement is evaluated by experimental laws of power and Hall-Petch types with a view to permitting the applicability of the resulting expressions.

EFFECT OF SCANDIUM ON THE CORROSION BEHAVIOR OF THE CASTING Al-Cu ALLOYS IN NACL SOLUTION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 978-983 ◽  
Author(s):  
WENGUI ZHAO ◽  
JINGUO WANG ◽  
JINGQI HOU ◽  
QICHUAN JIANG
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Measurement ◽  
Immersion Test ◽  
Nacl Solution ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Sc Addition ◽  
Equiaxed Grains ◽  
Better Than

Corrosion behavior of the casting Al - Cu alloys with and without Sc addition was studied by both the immersion test and electrochemical measurement methods. The results show that pitting corrosion was found on the surfaces of these alloys in 3.5 wt .% NaCl solution, while the corrosion resistance of the Al - Cu alloys with Sc is better than that of the Al - Cu alloy without Sc . With increasing Sc content, the corrosion resistance of the present Al - Cu alloys varies significantly, and the 0.1 wt .% Sc alloy has the best corrosion resistance. Also, the corrosion potential of the present alloys with Sc is shifted positively compared with that of the alloy without Sc by electrochemical measurement, indicating that the alloys with Sc have better corrosion resistance. The microstructures of the Al - Cu alloys change from the coarse grains to the fine equiaxed grains due to Sc addition, which is responsible for the reduced susceptibility to corrosion and the enhanced corrosion resistance of the present alloys.

scholarly journals Plastic straining and concomitant microstructure recrystallization of Ni-Cu alloy in the undercooled condition

2022 ◽  
Vol 1217 (1) ◽  
pp. 012005
Author(s):  
H An ◽  
N J Siambun ◽  
B L Chua ◽  
M J H Gan
Keyword(s):  
Rapid Solidification ◽  
Solidification Structure ◽  
Dislocation Network ◽  
Comparative Experiment ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Equilibrium Solidification ◽  
Strong Deformation ◽  
Rapidly Solidified ◽  
Microstructure And Microtexture

Abstract Microstructure and microtexture of rapidly solidified undercooled Ni-Cu alloys were investigated. The characteristic undercooling of Ni80Cu20 alloy was determined as 45K, 90K and 160K. Dendrite deformation due to rapid solidification led to strong deformation microtexture. Due to recrystallization upon annealing after recalescence, many subgrains were formed in the microstructure. Further, annealing the quenched alloy at 900°, new microtextures and subgrains were formed, which was due to recrystallization and dislocation network rearrangement. The results of comparative experiment proved the recrystallization mechanism of the microstructure refinement in the non-equilibrium solidification structure of the undercooled binary alloy

Plastic deformation of θ ' in Al-4%Cu alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 576-577
Author(s):  
Shrikant P. Bhat
Keyword(s):  
Deformation Behavior ◽  
Room Temperature ◽  
Electron Microscopic Observation ◽  
Bulk Alloy ◽  
Electron Microscopic ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Orowan Mechanism ◽  
The Subject ◽  
Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

Researched on the Corrosion Resistance of Ni-Cr-Mo-Cu Alloy to Aqueous Change with the APF in Regular Way: an Approach of Quantum Electrochemistry

2011 ◽  
Vol 55-57 ◽  
pp. 378-381
Author(s):  
Li Hua Pan ◽  
Rui Cheng Yang
Keyword(s):  
Corrosion Resistance ◽  
Cathodic Current ◽  
Cu Alloy ◽  
Cu Alloys

The corrosion resistance of Ni-Cr-Mo-Cu alloys designed by formula APF=4Cr/(2Mo+Cu) to aqueous depend on the APF is investigated. The cathodic current of corrosion reactions was expressed as the quantum electrochemical equation. It is discussed that the APF controls the corrosion resistance to aqueous.

scholarly journals Formation of the Equiaxed Grains in Pure Aluminum and Al-0.2%Cu Alloy Ingots

1970 ◽  
Vol 34 (8) ◽  
pp. 802-807
Author(s):  
Akira Suzuki ◽  
Jitsuhito Nakamura ◽  
Toshimasa Sakamoto
Keyword(s):  
Pure Aluminum ◽  
Cu Alloy ◽  
Equiaxed Grains

scholarly journals Kinetic Monte Carlo Simulation of Clustering in an Al-Mg-Si-Cu Alloy

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4523
Author(s):  
Qilu Ye ◽  
Jianxin Wu ◽  
Jiqing Zhao ◽  
Gang Yang ◽  
Bin Yang
Keyword(s):  
Activation Energy ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Complex Interaction ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Simulation Results ◽  
Small Clusters ◽  
First Time

The mechanism of the clustering in Al-Mg-Si-Cu alloys has been a long-standing controversial issue. Here, for the first time, the mechanism of the clustering in the alloy was investigated by a Kinetic Monte Carlo (KMC) approach. In addition, reversion aging (RA) was carried out to evaluate the simulation results. The results showed that many small-size clusters formed rapidly in the early stages of aging. With the prolongation of aging time, the clusters merged and grew. The small clusters formed at the beginning of aging in Al-Mg-Si-Cu alloy were caused by initial vacancies (quenching vacancies). The merging and decomposition of the clusters were mainly caused by the capturing of vacancies, and the clusters had a probability to decompose before reaching a stable size. After repeated merging and decomposition, the clusters reach stability. During RA, the complex interaction between the cluster merging and decomposition leaded to the partial irregular change of the hardness reduction and activation energy.

Sign in / Sign up

Export Citation Format

Share Document