Multiphase Model of Semisolid Slurry Generation and Isothermal Holding During Cooling Slope Rheoprocessing of A356 Al Alloy

2018 ◽  
Vol 49 (4) ◽  
pp. 1925-1944 ◽  
Author(s):  
Prosenjit Das ◽  
Sudip K. Samanta ◽  
Biswanath Mondal ◽  
Pradip Dutta
Keyword(s):  
Isothermal Holding ◽  
Semisolid Slurry ◽  
Al Alloy ◽  
Multiphase Model ◽  
Cooling Slope

Behaviour of Semisolid Slurry Flows through a Channel

2016 ◽  
Vol 256 ◽  
pp. 146-152 ◽  
Author(s):  
Sudip Simlandi ◽  
Nilkanta Barman ◽  
Himadri Chattaopadhyay
Keyword(s):  
Rectangular Channel ◽  
Conservation Equation ◽  
Sheet Forming ◽  
Metal Sheet ◽  
Structural Parameter ◽  
Semisolid Slurry ◽  
Al Alloy ◽  
Semisolid State ◽  
Small Depth ◽  
Semisolid Alloy

In case of metal sheet forming of alloys in semisolid state, modelling of the process is very essential to predict flow behaviour, temperature distribution of the alloy etc. towards improvement of the product quality and to reduce manufacturing costs. Accordingly, the present work develops a model to predict the behaviour during metal sheet forming of an Al-alloy (A356) in semisolid state. The semisolid alloy passes through a rectangular channel having small depth and larger width. The alloy in semisolid state is cooled from the top at a controlled rate. In the model, the respective flow field is represented by the momentum conservation equation. The non-Newtonian behaviour of the semisolid slurry is incorporated considering the Herschel–Bulkley model. The agglomeration and de-agglomeration phenomena of the suspended particles under shear are represented using a time dependent structural parameter. The temperature field is predicted considering the transient energy conservation equation, and hence the fraction of solid is continuously updated. The solution considers an apparent viscosity of the semisolid alloy as a function of structural parameter, shear stress and shear rate. The governing equations are finally solved by finite difference method. The work predicts velocity, temperature and liquid fraction distribution of the semisolid slurry.

Effect of Isothermal Holding Temperature on Globularization of Primary Solid Phase in Multiplex-Type Slurry Cup

2006 ◽  
Vol 116-117 ◽  
pp. 239-242 ◽  
Author(s):  
Suk Won Kang ◽  
Dock Young Lee ◽  
Ki Bae Kim
Keyword(s):  
Automobile Industry ◽  
Solid Phase ◽  
Isothermal Holding ◽  
Cost Effective ◽  
Al Alloy ◽  
Liquid Region ◽  
Globular Structure ◽  
Semi Solid ◽  
Solid Liquid ◽  
Holding Temperature

In order to produce a high quality and cost effective part in the rheocasting process for an automobile industry it has been important to develop a slurry-on-demand process, which can manufacture the semi-solid slurry having a fine and globular structure of primary solid phase. The morphology of primary solid phase of semi-solid slurry is coarsened and globularized during an isothermal holding process in a solid-liquid region. Accordingly, in this paper, the microstructural evolution of semi-solid slurry during the isothermal holding at a various temperature in solid-liquid region was investigated to examine a coarsening and globularization behavior of primary solid phase. The semi-solid slurry of Al alloy was produced in a slurry maker using a multiplex-type slurry cup that we developed recently. A size of primary solid phase was the finer at the higher holding temperature, but under a constant holding time a roundness degree of primary solid phase was the lower at the lower holding temperature. Also, a coarsening rate of primary solid phase was not considered to be affected significantly by a holding temperature even though a little lower coarsening rate was obtained at the higher holding temperature.

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.

Research on the Preparation and Rheo-Casting of A356 Al Alloy by LSPWES Process

2012 ◽  
Vol 457-458 ◽  
pp. 69-73
Author(s):  
Man Huan Li ◽  
Guo Xing Tang ◽  
Wei Min Mao ◽  
Yong Feng Liu
Keyword(s):  
Proper Time ◽  
Great Influence ◽  
Injection Pressure ◽  
Experimental Results ◽  
Temperature Fields ◽  
Homogeneous Distribution ◽  
Semisolid Slurry ◽  
Al Alloy ◽  
Injection Speed ◽  
Filling Ability

The semisolid slurry of A356 Al alloy was prepared by low superheat pouring and weak traveling-wave electromagnetic stirring (LSPWES), and then the slurry was further soaked for proper time and finally rheo-cast into a rheo-casting sample in this paper. The experimental results show that if the melt of A356 Al alloy is poured at 630-650°C and meanwhile stirred by weak electromagnetic field for a short time, the most primary α-Al grains solidified in the slurry are spherical and only a few are rosette-like. The shape of primary α-Al becomes more spheroidal and more homogeneous distribution in the microstructure by the process of the uniform temperature fields. The experimental results also show that the slurry temperature, injection pressure and speed have a great influence on filling ability. The higher the slurry temperature, injection pressure and speed, the higher the slurry filling ability, the more easily the die cavity is filled. With the given rheo-casting sample, if only the slurry temperature should be equal to or more than 585°C, or the injection pressure is equal to or more than 20 MPa, or the injection speed should be equal to or more than 0.24m/s, the rheo-casting sample die cavity can be filled completely. The microstructure of the castings indicates that the shape, size and numbers of the primary α-Al grains in different parts of the castings are highly consistent. After being held at 535 °C for 5 h and then aged at 160 °C for 16 h, the tensile strength, elongation rate and hardness of the rheo-casting samples with the above process are respectively 321.5 MPa, 8.03% and 105.9HB.

Preparation and rheocasting of semisolid slurry of 5083 Al alloy with indirect ultrasonic vibration process

2011 ◽  
Vol 528 (29-30) ◽  
pp. 8635-8640 ◽  
Author(s):  
Shulin Lü ◽  
Shusen Wu ◽  
Chong Lin ◽  
Zuqi Hu ◽  
Ping An
Keyword(s):  
Ultrasonic Vibration ◽  
Semisolid Slurry ◽  
Al Alloy ◽  
Vibration Process ◽  
5083 Al Alloy

scholarly journals Microstructural Features and Wear Characteristics of Semi-Solid Processed A356 Aluminum Alloy

2018 ◽  
Vol 5 ◽  
Author(s):  
K. Raju ◽  
N. Gopi Krishna ◽  
L. Sankara Rao ◽  
S. N.Ojha
Keyword(s):  
Heat Treatment ◽  
Cold Water ◽  
Isothermal Holding ◽  
Hot Forging ◽  
Cold Forging ◽  
Al Alloy ◽  
T6 Heat Treatment ◽  
Solid Region ◽  
A356 Aluminum ◽  
Semi Solid

In the present study the microstructural features and tribological characteristics of hot forged A356 Al alloy subjected to SIMA (Strain induced melt activation) and T6 heat treatment (semi-solid) processes have been investigated. The SIMA process consists of hot forging of alloy at 325˚C followed by cold forging at room temperature, isothermal holding at 580˚C for 10 min and quenching. In case of T6 heat treatment, the hot forged alloy was solution treated at 540˚C for 4 hours followed by quenching in cold water and artificial aging at 155˚C for 3 hours. The microstructure of the alloy exhibited a spherical or globular morphology of the primary α-phase with uniform distribution of solutes in the interdendritic region. A detailed analysis of the solidification behaviour of the melt from semi-solid region of the alloy is reported. The reasons for the consequential changes in tribological properties of A356 Al alloy processed by SIMA andT6 heat treatment have been clearly brought out.

Wear Behavior of Cooling Slope Rheocast A356 Al Alloy

2015 ◽  
Vol 58 (6) ◽  
pp. 1054-1066 ◽  
Author(s):  
Prosenjit Das ◽  
Bijay K. Show ◽  
Aakash Rathore ◽  
Sudip K. Samanta
Keyword(s):  
Wear Behavior ◽  
Al Alloy ◽  
Cooling Slope

Semisolid Microstructural Evolution of Equal Channel Angular Extruded Mg-Al Alloy During Partial Remelting

2008 ◽  
Vol 141-143 ◽  
pp. 557-562 ◽  
Author(s):  
S.M. Liang ◽  
Rong Shi Chen ◽  
En Hou Han
Keyword(s):  
Solid Solution ◽  
Microstructural Evolution ◽  
Equal Channel Angular Extrusion ◽  
Isothermal Holding ◽  
Solution Treatment ◽  
Solid Particles ◽  
Al Alloy ◽  
Semisolid State ◽  
Effects Of Temperature ◽  
Spherical Grains

Using equal channel angular extrusion (ECAE) process, which combine the advantages of grain refinement and induced strain, for preparing semisolid billets is a relatively new Strain Induced Melt Activation(SIMA)method. This paper investigates the remelting and semisolid isothermal holding behavior of Mg-9Al alloy after ECAE processing at 350°C. It has been found that 2 passes ECAE-ed billets are qualified for obtaining spherical grains after remelting and isothermal holding treatment. Increasing the ECAE process from 2 passes to 8 passes has no further significant effects on the size and roundness of the solid particles at the semisolid state. The effects of temperature and isothermal holding time on microstructural evolution have also been investigated. In addition, the solid solution treatment before the ECAE processing affected greatly on microstructural evolution of the alloy during ECAE processing and thus the following remelting and isothermal holding behavior. The Mg17Al12 precipitates were uniformly decomposed from the saturated solid solution in the solutionized samples during ECAE processing. The coalescence of grains together with the self-blocking effect generated more entrapped liquid in the solutionized sample at semisolid state. Moreover, the solid particles of solutionized samples have bigger size and grow faster, which are detrimental to SSM processability.

Evolution Characteristics of Primary Phase in A356 Al Alloy during Isothermal Holding in Solid-Liquid Phase Region

2011 ◽  
Vol 421 ◽  
pp. 39-42
Author(s):  
Zheng Liu ◽  
Kai Cao ◽  
Hong Biao Xu ◽  
Mei Yan Huang
Keyword(s):  
Liquid Phase ◽  
Isothermal Holding ◽  
A356 Alloy ◽  
Phase Region ◽  
Primary Phase ◽  
Al Alloy ◽  
Evolution Characteristics ◽  
Solid Liquid ◽  
Holding Temperature

Evolution characteristics of primary phase in A356 alloy at the different isothermal holding temperatures and time were investigated. The results showed that there were the effects of the isothermal holding temperature and time on the evolution of primary phase, and microstructure changed from dendritic-like to rosette-like, and then to particle- or globular-like with the decrease of holding temperature. The suitable technology in the test was obtained, in which when being held at 600°C for 5min, the roundness and size of primary became better.

Optimization of processing parameters of cooling slope process for semi-solid casting of ADC 12 Al alloy

2018 ◽  
Vol 40 (6) ◽  
Author(s):  
Sujeet Kumar Gautam ◽  
Nilrudra Mandal ◽  
Himadri Roy ◽  
Aditya Kumar Lohar ◽  
Sudip Kumar Samanta ◽  
...  
Keyword(s):  
Processing Parameters ◽  
Al Alloy ◽  
Cooling Slope ◽  
Semi Solid ◽  
Slope Process
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