CALPHAD Approach to Understand the Semi-Solid Processing Parameters of Al-6Si-4Cu Alloy

There is a strong demand for high-strength aluminum alloys such as 7075 aluminum alloy to be applied for rheocasting industry. The overriding challenge for the application of 7075 alloy is that its solid fraction is very sensitive to the variation of temperature in the range of 40% ~ 50% solid fraction, which inevitably narrows down the processing window of slurry preparation for rheocasting process. Therefore, in this work, a novel method to prepare semi-solid slurry of the 7075 alloy, so called Enthalpy Control Process (ECP), has been developed to grapple with this issue. In the method, a medium-frequency electromagnetic field was applied on the outside of slurry preparation crucible to reduce the temperature difference throughout the slurry. The effect of processing parameters, including heating power, heating time, the initial temperature of crucible and melt weight, on the temperature field of the semi-solid slurry was investigated. The results exhibited that although the all the processing parameters had a great influence on the average temperature of the slurry, heating time was the main factor affecting the maximum temperature difference of the slurry. The optimum processing parameters during ECP were found to be heating power of 7.5 KW, the initial temperature of crucible of 30 °C ~ 200 °C and melt weight of 2 kg.

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Rheoforging of thin case for IT devices with optimal process parameters and new type die design

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406213495768 ◽

2013 ◽

Vol 228 (6) ◽

pp. 1021-1028

Author(s):

Yong Phil Jeon ◽

Amir Bolouri ◽

Hyung Yoon Seo ◽

Jong Deok Kim ◽

Chung Gil Kang

Keyword(s):

Mechanical Properties ◽

Cell Phone ◽

Processing Parameters ◽

Die Design ◽

Electromagnetic Stirring ◽

Forming Process ◽

Processing Technologies ◽

Promising Tool ◽

New Type ◽

Semi Solid

The latest trend in the cell phone component industry to use aluminium and magnesium alloys has resulted in the advanced processing technologies. Semi-solid forming process that is advantageous for the mass production of thin parts with complex shapes have been of interest as a promising tool for near net-shape manufacturing. This study describes a semi-solid forming process for the development of a 1 mm-thick cell phone case by using the rheological material prepared by electromagnetic stirring equipment. Thus, a new type of die design for indirect rheoforging was proposed to efficiently control the primary α-Al phase particles in the thin part under rheological conditions. Their microstructure and mechanical properties were investigated and compared to parts produced without electromagnetic stirring. Those products fabricated by electromagnetic stirring had better mechanical properties and globular microstructures than those fabricated without electromagnetic stirring. Several processing parameters such as punch velocity (30 mm/s), punch pressure (75–250 MPa), stirring time (10 s), and solid fraction (0–20%) were used. The optimal condition that resulted in a defect-free component with the improved mechanical properties was explained and discussed.

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Mini-Thixoforming of High-Alloyed CPM REX 121 Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.1156 ◽

2014 ◽

Vol 887-888 ◽

pp. 1156-1160 ◽

Cited By ~ 1

Author(s):

David Aišman ◽

Kateřina Rubešová ◽

Šárka Mikmeková

Keyword(s):

Total Content ◽

Processing Parameters ◽

Alloying Elements ◽

Forming Process ◽

Technological Complexity ◽

Complex Carbides ◽

Conventional Methods ◽

Semi Solid ◽

Small Parts ◽

Suitable Processing

Thixo-forming is an unconventional semi-solid forming process, by which complex-shaped products can be manufactured using a single forming operation. It can even be applied to difficult-to-form materials, including those which are impossible to process by conventional methods. Today, commercial semi-solid processing is used for low-melting materials, primarily aluminium and magnesium alloys. Due to its technological complexity, thixo-forming of high-melting alloys is still under development. For this reason, the present experimental programme was focused on the tool steel CPM REX 121 with a melting point above 1200 °C produced by powder metallurgy. The total content of alloying elements in this steel is 37.5 %. Owing to the high levels of alloying elements, namely Co, Mo, W, V and Cr, this material cannot be formed by conventional methods. The purpose of the present experiment was to explore its potential for forming in semi-solid state and to find suitable processing parameters. Experimental forming took place in a mini-thixoforming die, a tool specially-developed for this thixo-forming variant intended for producing very small parts. The resulting microstructures were examined by means of optical and electron microscopy. It was found that semi-solid processing leads to the development of microstructure with austenitic grains, martensite, chromium and V-W-Mo complex carbides and also a eutectic formed by partial melting of carbides.

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Effect of Low-Voltage Electric Current Pulse on Semi-Solid Microstructure of Magnesium Alloy AZ91D

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.1613 ◽

2011 ◽

Vol 399-401 ◽

pp. 1613-1619

Author(s):

Quan Zhou ◽

Le Ping Chen ◽

Jian Yin

Keyword(s):

Electric Current ◽

Current Pulse ◽

Low Voltage ◽

Processing Parameters ◽

Dynamic Factor ◽

Semisolid Slurry ◽

Az91d Alloy ◽

Electric Current Pulse ◽

Alloy Az91d ◽

Semi Solid

The effect of discharging cycle, voltage, capacitance and time on solidified microstructure of semi-solid slurry of AZ91D alloy treated with Low-Voltage Electric Current Pulse(LVECP) was investigated in this paper. The experimental results show that primary grains of AZ91D alloy were refined apparently, the morphology dendrites of α-Mg were changed by electric current pulse and the nondendritic structure of semi-solid slurry of AZ91D alloy could be obtained with appropriate processing parameters. The decrease of discharging cycle and the increase of discharging voltage and time to prepare semisolid slurry by LVECP discharge promotes the formation of fine α-Mg grains. It is proposed that LVECP treatment created a new dynamic factor for nucleation so that the number of nuclei increased, which restrained the formation of large primary α-Mg dendrites and created a base to form spherical crystals of primary α-Mg. The stronger temperature fluctuation in the melt with many rosette primary α-Mg caused by LVECP discharge and the remelting of the secondary arm roots in the same time are the most important reasons for formation of spherical primary α-Mg grains.

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Casting Wear-Resistant Functionally Gradient Ferrous Alloys via Partial Solidification Processing

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.192-193.506 ◽

2012 ◽

Vol 192-193 ◽

pp. 506-511

Author(s):

Stephen Midson ◽

David J. Browne

Keyword(s):

Mild Steel ◽

Processing Parameters ◽

Gradient Material ◽

Solidification Processing ◽

Cast Irons ◽

Ferrous Alloys ◽

Functionally Gradient ◽

Steel Processing ◽

Semi Solid ◽

First Time

The CDC (Cast-Decant-Cast) Process is novel semi-solid processing method for joining two alloys, allowing the production of components from two or more alloys. The process produces a functionally gradient material (FGM) which, instead of having a sharp interface between the two alloys, features a transition region exhibiting a smooth gradient in concentration, microstructure and properties. Functionally gradient materials provide engineers with the flexibility to design components with different material properties at different locations. The details of the CDC Process are described. This paper, for the first time, provides information regarding the fabrication of functionally gradient castings from steels, cast irons and cobalt alloys. The first example involves the production of functionally gradient castings from a Ni-Hard cast iron + mild steel. The second example describes the production of functionally gradient castings from Stellite + mild steel. Processing parameters are documented and microstructures of the castings described.

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Preparation of Semi-Solid Billet with Less Liquid Content of 7A09 Aluminum Alloy by Partial-Melting Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1795 ◽

2009 ◽

Vol 79-82 ◽

pp. 1795-1798

Author(s):

Wei Wei Wang ◽

Jian Li Song ◽

Jing Bo Yu

Keyword(s):

Aluminum Alloy ◽

Optical Microscopy ◽

Partial Melting ◽

Microstructure Evolution ◽

Processing Parameters ◽

Liquid Content ◽

Melting Method ◽

Wide Range ◽

Fine Microstructure ◽

Semi Solid

Preparation of semi-solid microstructure with less liquid content of 7A09 aluminum alloy industrial extrusion billets is studied in this paper. In the treatment, melting-stirring and predeformation of the alloy billets are not required. The influences of different heating temperatures and insulation time on the microstructure evolution are studied and the obtained microstructure is observed and analyzed by optical microscopy. The results indicate that a fine microstructure can be obtained with the proposed process and the processing parameters can be controlled over a wide range. The liquid content can be controlled within a certain range.

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The key attributes of processing parameters on semi-solid metal casting: An Overview

E3S Web of Conferences ◽

10.1051/e3sconf/202130901089 ◽

2021 ◽

Vol 309 ◽

pp. 01089

Author(s):

Devendra Pratap Singh ◽

Vijay Kumar Dwivedi ◽

Mayank Agarwal

Keyword(s):

Global Economy ◽

Lower Cost ◽

Processing Parameters ◽

Current Status ◽

Reinforcement Particle ◽

Technological Advancement ◽

Matrix Composites ◽

Current Perspective ◽

Semi Solid ◽

Day By Day

Commercialization of the developed technology is a prime factor for any nation and sector to retain its existence in this global economy. Day by day the technological advancement touching new high in various sectors like the automobile and aircraft industries but high design efficiency is achieved only when it is complemented by appropriate material. In the list newer addition is MMCs (Metal Matrix Composites) which are favorable because of their lower cost achieved by cheaper reinforcement, easy processing, and capabilities of mass production. In recent days, the importance of semi-solid casting has been well accepted among various processing routes for aluminum alloys despite many challenges in terms of process parameters like porosity, agglomeration, non-uniform reinforcement particle distribution, low wettability, and engulfment, and this is a main consideration for the present work. Semi-solid casting is considered to be one of the most important and effective manufacturing processes of aluminum alloy for viable mechanical and metallurgical properties in the current perspective of product requirement and competitiveness. A glimpse of the current status is presented, which shows the potential of the process which can be utilized by the industries for several benefits. In a nutshell, it can be found that process has the capability of alteration by the use of different scraps and also have flexibility according to the processing parameters like stirring, pouring temperature, type of reinforcements, etc.

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

Materials Proceedings ◽

10.3390/iec2m-09240 ◽

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.

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Effect of Semi-Solid Processing on the Microstructure and Mechanical Properties of Aluminum Alloy Chips with Eutectic Mg2Si Intermetallics

Metals ◽

10.3390/met11091414 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1414

Author(s):

Yong Guk Son ◽

Sung Soo Jung ◽

Yong Ho Park ◽

Young Cheol Lee

Keyword(s):

Mechanical Properties ◽

Aluminum Alloy ◽

Eutectic Reaction ◽

Microstructural Analysis ◽

Aluminum Matrix ◽

Processing Parameters ◽

Holding Time ◽

Mg2si Phase ◽

Microstructure And Mechanical Properties ◽

Semi Solid

This study reports the microstructural changes and mechanical properties of high-strength aluminum alloy chips prepared in the semi-solid state at different temperatures, pressures, and holding times. In semi-solid processes, these processing parameters must be optimized because they affect the microstructure and mechanical properties of the chips. In microstructural analysis, these parameters clearly influenced the spheroidization of the aluminum matrix. The aluminum matrix was uniformly spheroidized after semi-solid processing, and the densities of the final samples increased with the holding time. After 30 min holding time at a given temperature, the density approached the theoretical density, but the compressive strength of the samples seriously deteriorated. Meanwhile, fracture surface investigation revealed a deformed Mg2Si phase, which is formed through a eutectic reaction. The strength of this phase significantly decreased after increasing the holding time of the semi-solid processing from 10 to 30 min. Therefore, deformation of the Mg2Si phase caused by diffusion of aluminum into this phase can be a key factor for the decrease in the mechanical properties of samples fabricated with 30 min holding time.

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Constitutive Model of Thixotropic Plastic Forming for Semi-Solid AZ61 Magnesium Alloy

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.116-117.639 ◽

2006 ◽

Vol 116-117 ◽

pp. 639-642 ◽

Cited By ~ 6

Author(s):

Hong Yan ◽

Bing Feng Zhou

Keyword(s):

Magnesium Alloy ◽

Volume Fraction ◽

Testing Machine ◽

Processing Parameters ◽

Liquid Volume ◽

Compression Tests ◽

Liquid Volume Fraction ◽

Az61 Magnesium Alloy ◽

Az61 Alloy ◽

Semi Solid

Uniaxial compression tests on semi-solid AZ61 alloy fabricated by stain-induced activation (SIMA) process and the conventional casts were carried out using the Gleedle-1500 dynamic material testing machine. The relationships between stress and stain were analyzed. The numerical relationships among processing parameters (strain rate z ε& strain z ε temperature T liquid volume fraction L f ) and stress were studied. The proposed constitutive equation was established for semi-solid AZ61 magnesium alloy using the multiple nonlinear regression method. A scientific basic provided for both numerical simulation of processing process of semi- solid AZ61 alloy and rational choice and control of processing parameters.

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