Dilatancy in semi-solid steels at high solid fraction

2017 ◽  
Vol 125 ◽  
pp. 187-195 ◽  
Author(s):  
K.M. Kareh ◽  
C. O'Sullivan ◽  
T. Nagira ◽  
H. Yasuda ◽  
C.M. Gourlay
Keyword(s):  
Solid Fraction ◽  
High Solid ◽  
High Solid Fraction ◽  
Semi Solid

Addition of Swarf to Produce a Semi-Solid Slurry during High Pressure Die-Casting of AS9U3 Aluminum Alloy

2019 ◽  
Vol 285 ◽  
pp. 271-276
Author(s):  
Hooman Hadian ◽  
M. Haddad-Sabzevar ◽  
Mohammad Mazinani
Keyword(s):  
High Pressure ◽  
Aluminum Alloy ◽  
Solid Fraction ◽  
Die Casting ◽  
Internal Cooling ◽  
High Solid ◽  
Cooling Agent ◽  
High Solid Fraction ◽  
Semi Solid ◽  
Pressure Die Casting

An internal cooling agent is used in rapid slurry forming (RSF) process to produce a high solid fraction slurry for a short period of time. In the process used in this research, the swarf which is known to be a low enthalpy material was added to the melt as the internal cooling agent. During the process, the swarf started to melt and a semi-solid slurry with a relatively high solid fraction was formed. This slurry was formed by exchanging the enthalpies between the low and high enthalpy materials. A commercial Al-Si-Cu alloy, i.e. AS9U3 Aluminum alloy, was used in this investigation. The microscopic examination showed that the Al-Si eutectic colonies start to melt during the melting process of swarf material resulting in the formation of globular Alpha-Al grains due to the multiplication of secondary dendrites arms. The fracture of dendrites arms and the subsequent spheroidization were suggested to be the origin of non-dendritic globular grains in the final microstructure. The amount of primary globular Alpha-phase was measured by the image analysis software. The results showed that during high pressure die-casting of AS9U3 Aluminum alloy using 4 mm thick samples, around 35 percent solid has been formed at the temperature of 580 oC.

K-0738 Dynamic Compressive Mechanical Properties of High Solid Fraction Aluminum Alloy in the Semi-solid State

2001 ◽  
Vol I.01.1 (0) ◽  
pp. 365-366
Author(s):  
Shusuke NAKANO ◽  
Toshiji MUKAI ◽  
Masahide KOHZU ◽  
Shigenori TANABE ◽  
Kenji HIGASHI
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Solid State ◽  
Solid Fraction ◽  
High Solid ◽  
High Solid Fraction ◽  
Semi Solid

Shear deformation of high solid fraction (>0.60) semi-solid SnPb under various structures

1995 ◽  
Vol 202 (1-2) ◽  
pp. 112-122 ◽  
Author(s):  
Christophe L. Martin ◽  
Stuart B. Brown ◽  
Denis Favier ◽  
Michel Suéry
Keyword(s):  
Shear Deformation ◽  
Solid Fraction ◽  
High Solid ◽  
High Solid Fraction ◽  
Semi Solid

Thixoforming of semi-solid AZ91D alloy with high solid fraction prepared by the RUE-based SIMA process

2017 ◽  
Vol 93 (9-12) ◽  
pp. 4317-4328 ◽  
Author(s):  
Yan Xu ◽  
Jianbo Jia ◽  
Chen Chen ◽  
Wenchao Liu ◽  
Shuyi Luo ◽  
...  
Keyword(s):  
Solid Fraction ◽  
Az91d Alloy ◽  
High Solid ◽  
High Solid Fraction ◽  
Sima Process ◽  
Semi Solid

Thixoforging of 7075 Aluminium Alloys at High Solid Fraction

2006 ◽  
Vol 116-117 ◽  
pp. 762-765 ◽  
Author(s):  
G. Vaneetveld ◽  
Ahmed Rassili ◽  
Jacqueline Lecomte-Beckers ◽  
H.V. Atkinson
Keyword(s):  
Solid State ◽  
Laminar Flow ◽  
Solid Fraction ◽  
High Speed ◽  
High Performance ◽  
Stick Slip ◽  
High Solid ◽  
High Solid Fraction ◽  
Semi Solid ◽  
7075 Alloy

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.5<fs<1), which involves the processing of alloys in the semi-solid state. 7075 alloy has been used as a feedstock for thixoforming in order to investigate thixoformability of a high performance aluminium alloy at high solid fraction. The microstructure in semi-solid state consists of fine spheroidal solid grains surrounded by liquid. Thixo behaviour allows laminar flow that avoids macro-porosity and other casting defects and gives better mechanical properties; so we can reduce the weight of functional parts. Higher solid fraction of 7075 alloy is less sensitive to temperature, avoids metal splash at high speed, allows laminar flow at high speed and gives a good smooth surface without stick-slip phenomenon. The process is quicker with less energy and so the production rate increases and the tool has longer life. However, high solid fraction promotes freezing flow because of faster solidification and the lack of liquid phase. This freezing flow creates solid/liquid segregation and increases the forming force.

Microstructures and Properties of Hypoeutectic Al-Si Alloy Extruded in Semi-Solid State

2012 ◽  
Vol 152-154 ◽  
pp. 326-330 ◽  
Author(s):  
Da Zhi Zhao ◽  
Fu Xiao Yu ◽  
Fang Liu ◽  
Ke Zhun He ◽  
Liang Zuo
Keyword(s):  
Solid State ◽  
Solid Fraction ◽  
Direct Chill ◽  
High Solid ◽  
High Solid Fraction ◽  
Fine Microstructure ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum ◽  
Semi Solid ◽  
Spherical Grains

The microstructures and properties of AlSi7Mg alloy extruded at 575°C in semi-solid state were studied for analyzing the extruding feasibility of the casting aluminum alloy in high solid fraction. The results show that the microstructure of AlSi7Mg alloy through low-superheat direct chill (DC) casting mainly consists of the homogeneous, fine rosette-shaped grains. The microstructure of the billet reheated at 575°C in 15min is composed of stable and near- spherical grains, which are suitable for thixoforming in high solid fraction. Extruded at 575°C in the semi-solid state, the facial-smoothed parts of AlSi7Mg alloy with homogeneous, fine microstructure across the section is obtained, and the properties of extruded part are improved obviously.

scholarly journals Improvement in Thixoforging of 7075 Aluminium Alloys at High Solid Fraction

2008 ◽  
Vol 141-143 ◽  
pp. 707-712 ◽  
Author(s):  
G. Vaneetveld ◽  
Ahmed Rassili ◽  
Jean Christophe Pierret ◽  
Jacqueline Lecomte-Beckers
Keyword(s):  
Mechanical Properties ◽  
Solid Fraction ◽  
Aluminium Alloys ◽  
High Speed ◽  
High Performance ◽  
Solidification Rate ◽  
High Solid ◽  
High Solid Fraction ◽  
Semi Solid ◽  
7075 Alloy

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.5<fs<1). 7075 aluminium alloys have been used as a feedstock for thixoforging in order to investigate thixoformability of a high performance aluminium alloy at high solid fraction. Higher solid fraction of 7075 alloy is less sensitive to temperature, avoids metal splash at high speed and allows laminar flow at high speed. Hot tool combined with lubricant tool coating are used to slow down the solidification rate of the high solid fraction metal by decreasing thermal exchanges with the tool. Improved thermal and forming parameters [1-2] will be applied to produce an automotive component by thixoforging and mechanical properties have been measured from tensile samples. High mechanical properties are obtained after T6 thermal treatment.

Modeling of Semi-Solid A356 Alloy under Upsetting Process

2006 ◽  
Vol 116-117 ◽  
pp. 622-625
Author(s):  
M. Shakiba ◽  
Hossein Aashuri
Keyword(s):  
Solid Fraction ◽  
Yield Criterion ◽  
Flow Behavior ◽  
A356 Alloy ◽  
Two Phase ◽  
Thermomechanical Process ◽  
Modeling Process ◽  
High Solid Fraction ◽  
Flow Through ◽  
Semi Solid

The flow behavior of a semi-solid A356 alloy at high solid fraction was studied. The mushy zone was considered as an effective two-phase, so that the solid continuum can be compressible porous media, and the liquid phase interaction with the solid skeleton was of Darcy type. The semi-solid flow through the upsetting test was modeled in ABAQUS finite element method software. The Gurson yield criterion has been developed for the modeling process of the flow behavior of solid porous medium. Specimens were globulized by a thermomechanical process and then were tested for various percentages of upsetting. The distribution of solid fraction along the radius of the specimens at different height reduction showed a good correlation with model prediction.

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