scholarly journals Microstructure Evolution and Solidification Behavior of a Novel Semi-Solid Alloy Slurry Prepared by Vibrating Contraction Inclined Plate

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1810
Author(s):  
Yan Liu ◽  
Minqiang Gao ◽  
Ying Fu ◽  
Weirong Li ◽  
Pan Yang ◽  
...  
Keyword(s):  
Inclination Angle ◽  
Microstructure Evolution ◽  
Vibration Frequency ◽  
A356 Alloy ◽  
Good Mechanical Property ◽  
Solid Alloy ◽  
Solidification Behavior ◽  
Inclined Plate ◽  
Pouring Temperature ◽  
Semi Solid

In this work, based on the A356 alloy, a novel Al–Si–Mg–Cu–Fe–Sr alloy with good mechanical property and high thermal conductivity was developed. The semi-solid slurry of the alloy was prepared via the vibrating contraction inclined plate. The microstructure evolution and solidification behavior of the alloy were investigated. The results demonstrated that, compared with the A356 alloy, the enhanced property of the Al–Si–Mg–Cu–Fe–Sr alloy was associated with the size of primary α-Al grains and morphology of eutectic Si phases. In addition, the preparation process parameters of semi-solid slurries, including the pouring temperature, inclination angle, and vibration frequency, had a crucial effect on the size and morphology of primary α-Al grains. The optimized pouring temperature, inclination angle, and vibration frequency were 670 °C, 45°, and 60 Hz, respectively. In this condition, for the primary α-Al grains, a minimum grain diameter of 64.31 µm and a maximum shape factor of 0.80 were obtained. This work provides a reference for the application of the alloy with high performance in the field of automobile and communication.

Influence of Process Papameters by Vibrational Cooling-Shearing Slope on Microstructures of Semi-Solid ZAlSi9Mg Alloy

2011 ◽  
Vol 211-212 ◽  
pp. 142-146 ◽  
Author(s):  
Wen Liu ◽  
Jian Bo Tan ◽  
Ji Qiang Li ◽  
Xu Ding
Keyword(s):  
Vibration Frequency ◽  
Mechanical Vibration ◽  
Solid Alloy ◽  
Pouring Temperature ◽  
Average Grain Size ◽  
Semisolid Alloy ◽  
Vibrational Cooling ◽  
Granular Crystal ◽  
Semi Solid ◽  
Casting Length

An experimental vibrational cooling-shearing slope was developed to prepare the ZAlSi9Mg semi-solid alloy. The results show that the molten alloy is nucleated heterogeneously under shearing of the gravitation and vibration on the inclined cooling plate surface. Primary α-Al phase converts gradually from the cellular dendrite into tiny spherical or granular crystal. Under 600°C of pouring temperature, 600mm of casting length and 50Hz of vibration frequency, the semisolid alloy melt with good microstructure can obtained. In the alloy melt the average grain size of the original α-Al phase is 50μm, and its shape factor is 0.71. Mechanical vibration can refine obviously the microstructure of ZAlSi9Mg alloy. Along with increasing of vibration frequency, the original α-Al phases are refined obviously, their roundness is improved.

Study of ECAP Processing Routes on Semi-Solid Microstructure Evolution of A356 Alloy

2008 ◽  
Vol 141-143 ◽  
pp. 397-402 ◽  
Author(s):  
M. Moradi ◽  
Mahmoud Nili-Ahmadabadi ◽  
B. Heidarian ◽  
Mohammad Habibi-Parsa
Keyword(s):  
Microstructure Evolution ◽  
A356 Alloy ◽  
Pressing Method ◽  
Processing Technologies ◽  
Angular Pressing ◽  
Cross Section Area ◽  
Section Area ◽  
Semisolid Forming ◽  
Semi Solid ◽  
Number Of Passes

Semi- solid (SS) processing technologies provide the production of metal parts with homogeneous, fine and globular – grained microstructure. This is one of the most successful and reliable methods to produce near net shape products exhibiting good mechanical properties. Production of feed stock with non-dendritic and spherical structure is the critical factors in semisolid forming. Among several processes to obtain a globular microstructure, the SIMA (strain induced melt activated) process is simple and advantageous with respect to equipment and eliminating the melting stage before reheating. In this research, Al (A356) has been used and in order to induce strain, ECAP (equal channel angular pressing) method has been applied. ECAP is a method in which a great strain is induced and severe plastic deformation without any changes in cross section area occurs. To induce larger strain, ECAP process was carried out on annealed specimens up to several passes in route A (no rotation of samples around linear axis between each pass) and Bc (90◦ rotation of samples around linear axis between each pass), in ambient temperature. The reheating condition was optimized and the comparison between different routes and number of passes was investigated. The microstructure evolution of deformed and reheated Al (A356) was characterized by SEM (Scanning electron microscopy) and optical microscopy. In addition, the relation between the induced strain with size and shape of particles has been studied.

Influence of Morphology on the Rheological Behavior of Semi-Solid A356 Aluminum Alloy

2006 ◽  
Vol 116-117 ◽  
pp. 601-605
Author(s):  
Heng Hua Zhang ◽  
Xian Nian Zhang ◽  
Guang Jie Shao ◽  
Luo Ping Xu ◽  
Yi Tao Yang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
A356 Alloy ◽  
Solid Alloy ◽  
A356 Aluminum Alloy ◽  
A356 Aluminum ◽  
Semi Solid

The morphology of semi-solid alloy is one of the key influence factors on the rheological behavior of slurry during die filling and the mechanical properties of formed parts. However, it is difficult to study such effect due to hard controlling of morphology in semi-solid state. In this paper, a self-developed Searle-type viscometer was used to determine the rheological behavior of A356 aluminum alloy in different morphology, which was refined with the salts mixture of K2TiF6 and KBF4. The results indicated that the flow behavior of refined A356 alloy in the semi-solid state possesses obviously thixotropic behavior under isothermal shearing condition with less time to reach steady state and lower steady apparent viscosity as compared to that of the A356 alloy. During continuous cooling at a constant shearing rate, the apparent viscosity of refined A356 slurry in the same solid fraction decreased with the content of Ti. It is shown from quantitative image analysis that the primary α-Al grain in the refined alloy evolves from dendrites to rosettes or sphericitys, and then tends to be rounder and finer in higher Ti content. The mechanism of the influence of morphology on rheological behavior was also discussed in this paper.

Formation of Globular Microstructure in A380 Aluminum Alloy by Cooling Slope Casting

2011 ◽  
Vol 264-265 ◽  
pp. 272-277 ◽  
Author(s):  
Nurşen Saklakoğlu ◽  
S. Gencalp ◽  
Şefika Kasman ◽  
İ.E. Saklakoğlu
Keyword(s):  
Aluminum Alloy ◽  
Slope Angle ◽  
Casting Process ◽  
Solid Particles ◽  
Inclined Plate ◽  
Pouring Temperature ◽  
Cooling Slope ◽  
Semi Solid ◽  
Cooling Slope Casting ◽  
The Many

Thixoforming and related semi-solid processing (SSP) methods require thixotropic materials. One of the many SSP techniques is the cooling slope (CS) casting process, which is simple and has minimal equipment requirements, and which is able to produce feedstock materials for semisolid processing. When the feedstock is reheated to the semisolid temperature range, non-dendritic, spheroidal solid particles in a liquid matrix suitable for thixoforming are obtained. In this study, equipment for the CS technique was first established, and then the effects of the pouring temperature and inclined slope angle on the microstructures of A380 aluminum alloy (ISOAlSi8Cu3Fe) were studied. Optimum parameters for thixoforming experiments were selected, and it was found that the microstructure produced by the inclined plate depended on its angle and the pouring temperature.

Rotational Rheology of A356 Semi-Solid Alloy at Low Solid Fractions

2014 ◽  
Vol 1019 ◽  
pp. 74-80 ◽  
Author(s):  
Amin Jabbari ◽  
Seyedali Ali Sadough ◽  
Vahid Pouyafar
Keyword(s):  
Flow Behavior ◽  
Isothermal Holding ◽  
A356 Alloy ◽  
Structural Parameter ◽  
Theoretic Model ◽  
Solid Alloy ◽  
Commercial Development ◽  
Aerospace Applications ◽  
Rate Step ◽  
Semi Solid

The main goal of investigations on semi-solid metal processing is to produce complex parts with enhanced mechanical properties. Flow behavior and die filling in semi-solid processing is an intrest area of researchers. A comprehensive understanding of the behavior of the under investigation metallic slurry is the design key of a successful manufacturing process. In this way the material’s transient response is very important for understanding of the rheological properties and also further commercial development of the process. The material used in this research is an Al-Si alloy which is widely used in automotive and aerospace applications. The experiments were conducted using a Searl rheometer which is specially designed for high temperature rheological measurements. For rheological tests of semi-solid alloy in different solid fractions, the isothermal holding and shear rate step change experiments were examined. Using practical rheological results, a single phase thixotropic model has been derived and adopted with measurements. The investigated alloy behavior was obviously thixotropic which is quantified in a theoretic model. Also instantaneous rheopectic behavior was observed for this alloy. The state of the microstructure has been applied through a structural parameter. The presented model for A356 alloy fits well with the experiments.

Microstructure Evolution during Semi-solid Isothermal Holding of Liquidus Cast Strontium-Modified A356 Alloy

2018 ◽  
Vol 71 (11) ◽  
pp. 2707-2712 ◽  
Author(s):  
Jayakrishnan Nampoothiri ◽  
C. Muthuraja ◽  
I. Balasundar ◽  
K. R. Ravi
Keyword(s):  
Microstructure Evolution ◽  
Isothermal Holding ◽  
A356 Alloy ◽  
Semi Solid

Modelling of Extrusion Process for Aluminium A356 Alloy

2014 ◽  
Vol 217-218 ◽  
pp. 188-194 ◽  
Author(s):  
Sudip Simlandi ◽  
Nilkanta Barman ◽  
Himadri Chattaopadhyay
Keyword(s):  
Shear Stress ◽  
Solid State ◽  
Numerical Solutions ◽  
Energy Requirement ◽  
A356 Alloy ◽  
Extrusion Process ◽  
Solid Alloy ◽  
Governing Equations ◽  
Semisolid Alloy ◽  
Semi Solid

In the present work, a model is developed to study extrusion process of A356 alloy in semi-solid state. The distinct rheology of the semisolid alloy reduces energy necessity during extrusion process. Accordingly, a proper rheological model of the alloy is considered in the model towards a detailed study of the process. A combination of analytical and numerical solutions is considered for solving the governing equations. The work finally predicts distribution of velocity and shear stress of the alloy under shear in the considered domain. It also predicts the energy requirement during the extrusion process. It is demonstrated that for semisolid extrusion, reasonably less energy is required as compared to a conventional extrusion process Keywords: Extrusion, semi-solid alloy, apparent viscosity, extrusion power

Semi-solid microstructure evolution during reheating of aluminum A356 alloy deformed severely by ECAP

2008 ◽  
Vol 466 (1-2) ◽  
pp. 67-72 ◽  
Author(s):  
S. Ashouri ◽  
M. Nili-Ahmadabadi ◽  
M. Moradi ◽  
M. Iranpour
Keyword(s):  
Microstructure Evolution ◽  
A356 Alloy ◽  
Semi Solid ◽  
Aluminum A356 Alloy
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