scholarly journals Microstructure and Rheological Properties of Semi-Solid 7075 Slurries Using SEED Rheocasting Process

2016 ◽  
Vol 256 ◽  
pp. 288-293 ◽  
Author(s):  
Amir Bolouri ◽  
Qin Fu Zhao ◽  
Pascal Côté ◽  
X. Grant Chen
Keyword(s):  
Rheological Properties ◽  
Grain Refinement ◽  
Parallel Plate ◽  
Grain Morphology ◽  
Transient State ◽  
High Strength ◽  
Processing Parameters ◽  
Seed Processing ◽  
Semi Solid ◽  
The Impact

The SEED rheocasting process was used to produce semisolid slurries of high strength 7075 aluminum wrought alloys. The effects of the SEED processing parameters on the microstructure of semisolid slurries were studied. The impact of grain refinement on the grain morphology and size was investigated. The rheological properties of semisolid 7075 alloys were characterized at different solid fractions using a parallel plate compression viscometer. Results indicated that the grain refinement could greatly improve the globularity of α-Al grains and rheoformability. The relationships between viscosity and shear rate at different solid fractions in the transient state for both unrefined and refined semisolid slurries were evaluated and discussed.

scholarly journals Effect of T6 on Mechanical Properties of TiB and Sr Modified ADC12/SiC Composite Produced by Stir Casting

2019 ◽  
Vol 130 ◽  
pp. 01023
Author(s):  
Pritamara Wahyuningtyas ◽  
Anne Zulfia Syahrial ◽  
Wahyuaji Narottama Putra ◽  
Budi Wahyu Utomo
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Solution Treatment ◽  
Grain Morphology ◽  
High Strength ◽  
Stir Casting ◽  
Strength Properties ◽  
Grain Refiner ◽  
Brake Shoe ◽  
The Impact

A study of ADC12 (Al-Si aluminium alloy) composite is conducted to obtain a more sustainable material with enhanced properties for automotive industry purpose, such as train's brake shoe and bearing application. For those kind of utilization, material with durability, good elastic modulus, thermal stability, wear resistance, and high strength properties is needed due to its exposure to high temperature and heavy continuous application. ADC 12 acts as the matrix, reinforced with 3 vf% micro-SiC with 5 wt% Mg wetting agent was fabricated by the stir casting method. The addition of 0.18 wt% Sr and 0.15 wt% TiB were expected to finer the grain morphology of the silicone eutectic phase and to acts as the grain refiner, respectively. Furthermore, T6 heat treatment was applied with aging temperature 150 °C, 170 °C, 190 °C, 210 °C, and 230 °C, following the prior 1 h 490 °C solution treatment. The results obtained in this work showed enhancement in tensile strength with the value of 213 MPa, hardness value 75 HRB, and wear resistance. These values increase up to 115 MPa for the UTS and 38 HRB for the hardness value, as the impact of the refined grains from both modifiers and heat treatment.

Numerical and Experimental Study on ECAP-Processing Parameters for Efficient Grain Refinement of AA5083 Sheet Metal

2019 ◽  
Vol 794 ◽  
pp. 315-323 ◽  
Author(s):  
Maximilian Gruber ◽  
Christian Illgen ◽  
Philipp Frint ◽  
Martin F.X. Wagner ◽  
Wolfram Volk
Keyword(s):  
Shear Strain ◽  
Grain Refinement ◽  
Sheet Metal ◽  
Electron Backscatter Diffraction ◽  
Superplastic Forming ◽  
Processing Parameters ◽  
Geometrical Parameters ◽  
Maximum Magnitude ◽  
Applied Model ◽  
The Impact

Equal-channel angular pressing (ECAP) is often used as effective tool for grain refinement for many different metallic materials. It is well known that grain size is an important microstructural feature influencing superplastic properties of fcc materials like aluminum alloys. The magnitude of introduced shear strain depends on geometrical parameters of the ECAP channel. In this contribution, the impact of different geometrical parameters of the ECAP channel on the resulting magnitude of introduced shear strain is analyzed. ECAP on AA5083 aluminum sheets with the dimensions of 200x200x1.8 mm3 is performed. Microhardness measurements reveal a considerable increase of hardness after ECAP and microstructural investigations by electron backscatter diffraction (EBSD) show the beginning formation of a deformation-induced substructure which is known to be a preliminary stage of the grain refinement process. It is assumed that this fine-grained microstructure results in an enhanced superplastic forming capability. Furthermore, a numerical model of the process based on the experimental results is established. The bending of the ECAP processed sheet metal as well as its microhardness are used for the validation of the model. The friction coefficient between the channel and the aluminum sheet significantly influences the results of the simulation. With the applied model different channel angles and inner corner radii are varied in order to determine a maximum magnitude of deformation resulting in sufficient grain refinement of the investigated material. With the help of the results gained in this study, suitable ECAP parameters for sheet metals can be derived that enable creating ultrafine-grained materials for superplastic forming operations.

Rheological Properties and Microstructure of Hypereutectic Semi-Solid Al-Si-Mg Alloys Using Rheocasting Route

2012 ◽  
Vol 192-193 ◽  
pp. 323-328 ◽  
Author(s):  
Mehand Tebib ◽  
Frank Ajersch ◽  
X. Grant Chen
Keyword(s):  
Solid State ◽  
Rheological Properties ◽  
Parallel Plate ◽  
Fluid Model ◽  
Flow Behavior ◽  
Microstructural Study ◽  
Shear Rates ◽  
Solid Phases ◽  
Semi Solid ◽  
Liquid And Solid Phases

The SEED rheocasting process was used to produce semi-solid slurries of hypereutectic Al-17Si-4.5Cu (A390) and Al-15Si-10.5Mg-4Cu alloys respectively. The rheological properties of these alloys in the semi-solid state were characterized at different deformation rates and at variable solid fractions using the parallel plate compression viscometry. The viscosity at different shear rates was calculated using a Newtonian fluid model for increments of deformation during compression. Microstructures of both alloys, after partial solidification and compression, were examined in order to characterize the flow behavior during deformation. The comparison of the viscosity between the A390 and Al-15Si-10.5Mg-4Cu alloys indicated that the high Mg containing alloy possessed a higher viscosity for the range of shear rates and solid fractions investigated. Rheological results showed that at a given solid fraction, the viscosity of both alloys decreased significantly with increasing shear rates, indicating a shear thinning behavior. In addition, a separation of liquid and solid phases was also observed for both alloys in the microstructural study of compressed semi-solid billets.

scholarly journals Optimization of Process Parameters on Microstructure and Mechanical Properties of ADC12 Alloy Aptomat Contact Fabricated by Thixoextrusion

2021 ◽  
Vol 3 (1) ◽  
pp. 29
Author(s):  
Lai Dang Giang ◽  
Nguyen Anh Tuan ◽  
Dao Van Luu ◽  
Nguyen Vinh Du ◽  
Nguyen Manh Tien
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Processing Parameters ◽  
Holding Time ◽  
Forming Process ◽  
Specimen Temperature ◽  
Optimization Of Process Parameters ◽  
Punch Velocity ◽  
Optimization Parameters ◽  
Semi Solid

The mechanical properties of thixoextrusion components can be improved by controllable processing parameters such as the solid fraction of alloy, holding time, punch velocity, heat treatment and die temperature. In this study, the effects of thixoforming parameters on the microstructures and mechanical properties of thixoextrusion ADC12 alloy Aptomat Contact are studied. ADC12 has excellent castability with high fluidity and low shrinkage rate, so it is widely used in industry, especially in automotive and motorcycle engine part casting. It is a near eutectic alloy with high strength and low ductility (1%). The optimization parameters mechanical properties were investigated by changing the punch velocity, specimen temperature and holding time. The results also indicated optimal value at punch velocity (15 mm/s), specimen temperature (560 °C) and holding time (5 min) which was changed microstructure from eutectic dendrite to globular grain, increasing the ductility (3.3%) of this alloy during the semi-solid forming process while the remaining mechanical properties lead to an increase in the quality of finished parts.

scholarly journals Role of Sodium Dodecyl Sulfate in Tailoring the Rheological Properties of High-Strength Gelatin Hydrogels

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 271
Author(s):  
Virginia Martin Torrejon ◽  
Yanqiu Deng ◽  
Guidong Luo ◽  
Bingjie Wu ◽  
Jim Song ◽  
...  
Keyword(s):  
Surface Tension ◽  
Sodium Dodecyl Sulfate ◽  
Rheological Properties ◽  
Sodium Dodecyl ◽  
High Strength ◽  
Gel Strength ◽  
Gelation Kinetics ◽  
Gelling Temperature ◽  
Dodecyl Sulfate ◽  
The Impact

Gelatin hydrogels are widely used materials that may require surfactants to adjust their solution’s surface tension for cell attachment, surface adsorption enhancement, or foaming. However, gelatin is a highly surface-active polymer, and its concentrated solutions usually do not require surfactants to achieve low surface tension. However, anionic surfactants, such as sodium dodecyl sulfate (SDS), interact strongly with gelatin to form complexes that impact its hydrogels’ rheological properties, influencing processability and functionality. Nevertheless, there is a lack of systematic research on the impact of these complexes on high gelatin content (i.e., high strength) hydrogels’ rheological properties. In this work, the SDS/gelatin ratio-dependent viscoelastic properties (e.g., gel strength, gelation kinetics, and melting/gelling temperature) of high-strength gelatin hydrogels were investigated using rheology and correlated to surface tension, viscometry, FTIR, and UV-Vis spectrophotometry. SDS–gelatin ratio was proved to be an important factor in tailoring the rheological properties of gelatin hydrogels. The gel strength, gelation kinetics, and melting/gelling temperature of the gelatin hydrogels linearly increased with SDS incorporation up to a maximum value, from which they started to decline. The findings of this work have wide applicability in tailoring the properties of gelatin–SDS solutions and hydrogels during their processing.

The SEED Technology for Semi-Solid Processing of Aluminum Alloys: A Metallurgical and Process Overview

2006 ◽  
Vol 116-117 ◽  
pp. 472-477 ◽  
Author(s):  
Joseph Langlais ◽  
Alain Lemieux
Keyword(s):  
Mechanical Properties ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Technology Program ◽  
Seed Technology ◽  
Solid Mixture ◽  
Seed Processing ◽  
Near Net Shape ◽  
Semi Solid ◽  
Slurry Preparation

As part of the foundry technology program, Alcan is developing a liquid-based slurrymaking process known as the SEED technology for semi-solid forming. The technology is presently entering the industrial and commercial stages, and will be used by the first customers in late 2006. The semi-solid process offers many advantages to economically fabricate near-net-shape parts having superior quality. The SEED process helps to overcome problems experienced with thixocasting and especially the high cost of feedstock. The SEED process involves two main steps: 1) heat extraction to achieve a desired liquid/solid mixture, and 2) drainage of an excess liquid to produce a self-supporting semi-solid slug that is formed under pressure. An overview of the industrial SEED technology advantages such as the alloy processing flexibility (A356, AA6061) and large slug dimensions and weights, is presented. The influence of the SEED processing parameters (slurry preparation) on the final mechanical properties and the microstructure evolution is also reported.

The Impact of Diffusion on Synthesis of High-Strength Titanium Alloys from Elemental Powder Blends

2010 ◽  
Vol 436 ◽  
pp. 113-121 ◽  
Author(s):  
Orest M. Ivasishin ◽  
Dmytro G. Savvakin
Keyword(s):  
Titanium Alloys ◽  
High Strength ◽  
Cost Effective ◽  
Processing Parameters ◽  
Elemental Powder ◽  
Strong Impact ◽  
Beta Titanium ◽  
Effective Manner ◽  
Powder Blends ◽  
The Impact

High strength near-beta titanium alloys are being increasingly used in industry due to their excellent combination of properties. Blended elemental powder metallurgy (BEPM) allows to produce the above alloys and parts from them in a cost-effective manner. However, the alloy synthesis is complicated by a big amount (up to 18 wt.%) of alloying elements which diffusional redistribution between alloying particles and titanium matrix has a strong impact on microstructure evolution. In this paper synthesis of the high-strength alloys from the powder blends based on hydrogenated titanium was studied. It was found that hydrogen strongly affects diffusion controlled processes upon synthesis, such as chemical homogenization, densification and grain growth through its influence on phase composition and defect structure of the blends. Optimization of the processing parameters allowed to produce uniform, nearly-dense alloys with reduced grain size, which mechanical properties met the requirements of corresponding specifications.

scholarly journals INFLUENCE OF PROCESSING PARAMETERS ON RHEOLOGICAL BEHAVIOR OF BENTONITE-BASED PICKERING EMULSION

2018 ◽  
Vol 8 (5) ◽  
pp. 442-447
Author(s):  
Saida TOUZOUIRT ◽  
Fetta KESSAL ◽  
Chanez BELAIDI ◽  
Dihia BOULHALFA
Keyword(s):  
Yield Strength ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Pickering Emulsion ◽  
Processing Parameters ◽  
The Other ◽  
Pickering Emulsions ◽  
Average Size ◽  
The Impact ◽  
Initial Viscosity

The aim of this work is to study the impact of processing parameters on the rheological properties of Pickering emulsions containing bentonite particles, CTAB, NaCl and soybean oil. Emulsification experiments were performed using mixing and homogenization at different speeds for 10 minutes. The effects of stirring speed and homogenization were investigated to determine the best conditions for producing a suitable Pickering emulsion for the intended application. In order to assess the influence of processing parameters on the Pickering emulsion rheological behavior average droplet size was measured and rheological tests were performed on all the emulsions samples. The rheological behavior of these emulsions is modeled by Casson's law. Results show that the stirring speed first decreases the average size of the droplets, and then an effect on the initial viscosity is observed. Increasing the stirring speed increases the values of the initial viscosity in contrast to the infinite viscosity which is influenced by the homogenization speed. On the other hand, these processing parameters significantly affect the values of the yield strength. Keywords: stirring speed, speed homogenization, rheological properties, Pickering emulsion.

Impact of Intensification Pressure and Grain Refiner on the Hot Tearing Susceptibility of a Semi-Solid Cast Al-Zn-Mg-Cu Alloy

2019 ◽  
Vol 285 ◽  
pp. 283-289
Author(s):  
Hai Yue Zhao ◽  
Da Quan Li ◽  
Min Luo ◽  
Stephen P. Midson ◽  
Qiang Zhu
Keyword(s):  
Aluminum Alloys ◽  
Grain Refinement ◽  
Hot Tearing ◽  
Commercial Application ◽  
Cast Aluminum ◽  
Grain Refiner ◽  
Cu Alloy ◽  
Intensification Pressure ◽  
Semi Solid ◽  
The Impact

The commercial application of wrought aluminum alloys to semi-solid casting would be extremely beneficial, as wrought alloys often exhibit better strength-ductility combinations than cast aluminum alloys. Semi-solid casting typically reduces the hot tearing tendency, as it requires a globular microstructure and produces grain refinement, but hot tearing often still occurs during the semi-solid die casting of complex-shaped components produced from wrought alloys. This study examined the impact of intensification pressure and grain refinement on the hot tearing tendency of an Al-Zn-Mg-Cu alloy. Semi-solid slurries were produced using the SEED (Swirled Equilibrium Enthalpy Device) process. A specially designed constrained rod mold was used to evaluate hot tearing. Results showed the tendency for hot tearing decreased with increasing of intensification pressure. Grain refinement (with 0.06Ti) was also found to be beneficial to the elimination of hot tearing.

scholarly journals COMPREHENSIVE MODIFICATION OF GELS POLYACRYLAMIDE

2016 ◽  
pp. 16-25
Author(s):  
Tatiana Shevchenko ◽  
Tatiana Shevchenko ◽  
Yulia Ustinova ◽  
Yulia Ustinova
Keyword(s):  
Amino Acids ◽  
Rheological Properties ◽  
High Efficiency ◽  
Chemical Nature ◽  
High Strength ◽  
Strain Rates ◽  
Physical Methods ◽  
Initial Yield Stress ◽  
Chemical Factors ◽  
The Impact

For successful use of flocculants it is necessary to give them new features artificially, among which the most important are rheological properties - shear stress at different strain rates. They can be changed while using methods of chemical and physical modifications and the most promising among them are physical methods of modification. Comparative rheological properties of polyacrylamides aqueous solutions without and with modification of the bifunctional connections of different chemical nature (glycols, amino acids) were given. The strengthening of the modification effect was achieved by the additional impact of physic-chemical factors: ultrasonic and microwaves with a frequency of 2.45 GHz for 10 s with a power of 700 watts. The thorough analysis of the rheological studies data for each flocculant was made. With modifying PG initial yield stress (Θf) increased 1.1-1.5 times, while with the modification by glycine, this value changed to 1.1-1.7 times. The optimal concentration of PE to obtain gels with high strength comprises: a modified GHG - 1.0%, modified by glycine with the influence of ULTRASONIC - 1.0% modified by glycine - 0.7%, modified by glycine with the impact of MVO - 0.3%, indicating high efficiency of the use of glycine and MVO. It was found out that Θf in the case of using PG - 1.5 times higher than that of the original (if sopt = 1.0%); when using the glycine - to 1.7 (sopt = 0.7%) higher than that of the original; in the using of glycine together with ULTRASONIC - in 1.5 times (when sopt = 0.1%) higher than that of the original, when using glycine in conjunction with MVO - in 1.9 times (if sopt = 0.3%).

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