scholarly journals The Influence of Liquid Surface Segregation on the Pitting Corrosion Behavior of Semi-Solid Metal High Pressure Die Cast Alloy F357

2009 ◽  
Vol 2 (1) ◽  
pp. 216-220 ◽  
Author(s):  
H. Moller ◽  
E. P. Masuku
Keyword(s):  
High Pressure ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Surface Segregation ◽  
Liquid Surface ◽  
Cast Alloy ◽  
Solid Metal ◽  
Die Cast ◽  
Semi Solid

The Heat Treatment of Rheo-High Pressure Die Cast 6xxx Series Al-Mg-Si-(Cu) Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 137-142 ◽  
Author(s):  
Heinrich Möller ◽  
Pfarelo Daswa ◽  
Gonasagren Govender
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Metal Forming ◽  
Solid Metal ◽  
Artificial Ageing ◽  
Limited Information ◽  
Cu Alloys ◽  
Die Cast ◽  
Semi Solid ◽  
6Xxx Series

Limited information is available regarding the heat treatment response of age-hardenable wrought Al-alloys produced by semi-solid metal forming. In this study, the effects of chemical composition, natural pre-ageing and artificial ageing on the T6 properties of rheo-high pressure die cast 6xxx series Al-Mg-Si-(Cu) alloys are investigated. A Cu-free alloy 6082 is compared with Cu-containing alloys 6013 and 6111. The effects of Mg:Si ratio of the alloys are also quantified by means of a comparison between alloys 6111 and 6013. Artificial ageing curves following either no or 5 days of natural pre-ageing are also presented.

EN AC-46500 Injected by Semi-Solid Rheocasting

2008 ◽  
Vol 141-143 ◽  
pp. 283-288 ◽  
Author(s):  
Manel Campillo ◽  
Maite T. Baile ◽  
Sergi Menargues ◽  
Antonio Forn
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Pressure ◽  
Structural Integrity ◽  
Tensile Tests ◽  
Simulation Software ◽  
Industrial Plant ◽  
Forming Process ◽  
Die Cast ◽  
Semi Solid

EN AC-46500 aluminium components are formed by Semi-Solid Rheocasting (SSR) in an industrial plant using a 700 tons high pressure machine. The dies wear was designed by the PLCO model of the ProCast simulation software. The components have had a good structural integrity and the mechanical properties after T6 treatment have been equivalent to that obtained by the same alloy by die cast. The present work describes the SSR forming process, the resulting microstructure as well as the optimization of the ageing heat treatment by hardness evolution. The results of the tensile tests make these clear.

scholarly journals Assessment of Mechanisms for Particle Migration in Semi-Solid High Pressure Die Cast Aluminium-Silicon Alloys

2020 ◽  
Vol 4 (2) ◽  
pp. 51
Author(s):  
Madeleine Law ◽  
Christopher Neil Hulme-Smith ◽  
Taishi Matsushita ◽  
Pär G. Jönsson
Keyword(s):  
High Pressure ◽  
Die Casting ◽  
Particle Migration ◽  
Silicon Alloys ◽  
High Pressure Die Casting ◽  
Die Cast ◽  
Semi Solid ◽  
Pressure Die Casting ◽  
Saffman Lift Force ◽  
Externally Solidified Crystals

In semi-solid metal high pressure die casting and in conventional high pressure die casting, it is common to find a defect band just below the surface of the component. The formation of these bands is not fully understood. However, there are several theories as how they occur, and it has been suggested that segregation is caused by the migration of aluminium-rich externally solidified crystals. In the present work the formation of these bands is investigated theoretically by reviewing suitable potential mechanisms for the migration of such crystals. Two mechanisms are identified as the most probable: Saffman lift force and the Mukai-Lin-Laplace effect. However, it was not possible to identify which of these two mechanisms acted in the case studies. Further testing is required to identify the mechanism that is causing the migration of the aluminium globules and suitable tests are proposed.

The Effect of Inverse Macro-Segregation on Fatigue Behavior of Die-Cast AM60 Magnesium Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 713-716 ◽  
Author(s):  
Soon Gi Lee ◽  
Gautam R. Patel ◽  
Arun M. Gokhale
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Magnesium Alloy ◽  
Fatigue Resistance ◽  
Surface Segregation ◽  
Fatigue Behavior ◽  
Eutectic Phase ◽  
Mg Alloys ◽  
Die Cast ◽  
Alloy Castings

The normal and inverse solute macro-segregation are known to occur in Al and other nonferrous alloy castings and have been well studied and documented. However, these phenomena have not been investigated in the high-pressure die-cast Mg-alloys. Consequently, the effects of macro-segregation on the mechanical properties of cast Mg-alloys have not been characterized. The objective of this contribution is to investigate the effects of inverse macro-segregation and porosity on the fatigue behavior of high-pressure die-cast AM60 alloy. It is observed that the inverse macro-segregation of eutectic phase at the cast surfaces adversely affects the fatigue behavior: the fatigue resistance decreases substantially due to the presence of the surface segregation.

Comparison of Corrosion Resistance of High Pressure Die-Cast and Semi-Solid Cast AZ91, AM60, Alloys and Respective Anodic Oxides

2013 ◽  
Vol 765 ◽  
pp. 618-622
Author(s):  
Carmine Genoni ◽  
Anna da Forno ◽  
Massimiliano Bestetti
Keyword(s):  
Heat Treatment ◽  
Aqueous Solution ◽  
High Pressure ◽  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Environment Friendly ◽  
Die Cast ◽  
Cast Alloys ◽  
Semi Solid

A comparison of corrosion resistance of die-cast and semi-solid cast AZ91and AM60 magnesium alloys was performed in corrosive medium by measurement of the open circuit potential and potentiodynamic scans. Before testing, a heat treatment was carried out on the semi-solid cast alloys. Moreover, electrochemical measurements were performed on the four different substrates anodized in the micro-arc regime in an environment friendly alkaline aqueous solution. The results could be correlated to the different microstructures of the samples produced by the different processes and to the different compactness/porosity of the oxides.

scholarly journals Filling, Feeding and Defect Formation of Thick-Walled AlSi7Mg0.3 Semi-Solid Castings

2016 ◽  
Vol 256 ◽  
pp. 222-227 ◽  
Author(s):  
Jorge Santos ◽  
Anders E.W. Jarfors ◽  
Arne K. Dahle
Keyword(s):  
High Pressure ◽  
Cross Sections ◽  
Surface Segregation ◽  
Defect Formation ◽  
Shear Bands ◽  
Casting Machine ◽  
Shrinkage Porosity ◽  
Cast Material ◽  
Lower Porosity ◽  
Semi Solid

Aluminium semi-solid castings have gained increased attention due to their superior mechanical properties, lower porosity compared to conventional high pressure die cast material. These characteristics suggests that semi-solid casting should be suitable to produce thick-walled structural components, yet most successful applications of semisolid casting have been for thin-walled components. There is a lack of understanding on filling and feeding related defect formation for semi-solid castings with thick-walled cross-sections. In the current study an AlSi7Mg0.3 aluminium alloy was used to produce semi-solid castings with a wall thickness of 10mm using a Vertical High Pressure Die Casting machine. The RheoMetalTM process was used for slurry preparation. The primary solid α-Al fraction in the slurry was varied together with die temperature. The evaluation of the filling related events was made through interrupted shots, stopping the plunger at different positions. Microscopy of full castings and interrupted test samples were performed identifying the presence of surface segregation layer, shear bands, gas entrapment, shrinkage porosity as well as burst feeding.

scholarly journals Influence of Microstructural Inhomogeneity on Fracture Behaviour in SSM-HPDC Al-Si-Cu-Fe Component with Low Si Content

2014 ◽  
Vol 217-218 ◽  
pp. 67-74 ◽  
Author(s):  
Mostafa Payandeh ◽  
Anders E.W. Jarfors ◽  
Magnus Wessen
Keyword(s):  
Surface Segregation ◽  
Fracture Behaviour ◽  
Tensile Specimen ◽  
Cast Material ◽  
Near Surface ◽  
Die Cast ◽  
Microstructural Inhomogeneity ◽  
Trapped Gas ◽  
Semi Solid ◽  
Si Content

In the current paper, a low-Si containing aluminium alloy (1.4-2.2% Si) was used to fabricate a complex shape telecom component using Semi-Solid High-Pressure Die Cast (SSM-HPDC), process. Microstructure and fracture characteristics were investigated. The cast material exhibited microstructural inhomogeneity, in particular macrosegregation in the form of liquid surface segregation bands in addition to sub-surface pore bands and gross centre porosity. Tensile specimen were taken from the cast components. Elongation and microstructural inhomogeneity were investigated and correlated. Fracture surfaces of the tensile specimen were examined under scanning electron microscope (SEM). The study showed that both near surface liquid segregation bands and subsurface porosity strongly affected the fracture behaviour. Dominant for loss of ductility were gross centre porosity. This centre porosity was found to be a combination of trapped gas and insufficient, irregular feeding patterns.

Fusion Welding of Rheocast Semi-Solid Metal (SSM) Processed Aluminium Alloy 7017

2012 ◽  
Vol 192-193 ◽  
pp. 161-166 ◽  
Author(s):  
Madeleine du Toit ◽  
Patronica Letsoalo ◽  
Heinrich Möller
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Aluminium Alloy ◽  
Die Casting ◽  
Solid Metal ◽  
Hot Tearing ◽  
High Pressure Die Casting ◽  
Near Net Shape ◽  
Semi Solid ◽  
Pressure Die Casting

Near-net shape casting of wrought aluminium alloys has proven to be difficult due to a tendency towards hot tearing during cooling. Rheocasting, or semi-solid metal (SSM) processing followed by high pressure die casting (HPDC), has recently been shown to be an effective alternative to conventional die casting, yielding near-net shape wrought aluminium alloy castings with less risk of hot tearing. This casting process involves pouring the liquid metal into a processing cup, which is then transferred into a coil for induction stirring and simultaneous forced air cooling. When the metal reaches the semi-solid casting temperature, the resultant slurry is transferred to a high pressure die casting machine and cast to near-net shape. This modifies the as-cast microstructure, yielding a more globular primary phase and results in mechanical properties in the -T6 condition closely approaching those of wrought material in the same condition. Little information is currently available on the response of SSM-HPDC material to welding. This project investigated the influence of autogenous laser and gas tungsten arc welding on the microstructure and mechanical properties of aluminium 7017 after rheocasting. It is possible to successfully weld this material without solidification or liquation cracking. The effect of welding on the rheocast microstructure in the heat-affected zone and weld metal was shown, and the hardness and tensile properties of the resulting joints in the as-welded condition were tested and related to the microstructures achieved.

Sign in / Sign up

Export Citation Format

Share Document