Solid fraction evolution characteristics of semi-solid A356 alloy and in-situ A356-TiB2 composites investigated by differential thermal analysis

2015 ◽  
Vol 22 (4) ◽  
pp. 389-394 ◽  
Author(s):  
S. Deepak Kumar ◽  
A. Mandal ◽  
M. Chakraborty
2006 ◽  
Vol 116-117 ◽  
pp. 622-625
Author(s):  
M. Shakiba ◽  
Hossein Aashuri

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.


2010 ◽  
Vol 649 ◽  
pp. 493-498 ◽  
Author(s):  
Ana Isabel Fernández-Calvo ◽  
Andrea Niklas ◽  
Jacques Lacaze

Both thermal analysis (TA) and differential thermal analysis (DTA) have been used since long to evaluate latent heat release and solid fraction evolution during solidification of metallic alloys. TA makes use of cooling curves recorded under "natural" cooling while DTA consists in recording the temperature difference between the sample temperature and an inert reference during a controlled cooling, i.e. at imposed constant cooling rate. In both cases, the solid fraction evolution is deduced from a calculation of the latent heat release as estimated by means of a heat transfer model. This paper provides a comparison of such evaluations performed on one Al-Si alloy.


2002 ◽  
Vol 35 (6) ◽  
pp. 664-668 ◽  
Author(s):  
E. H. Kisi ◽  
D. P. Riley

A unit-cell parameter anomaly observed during the precipitation and growth of Ti3SiC2from a Si-substituted TiC phase is interpreted as the release of latent heat. The observations are used to propose a powder diffraction method for conducting differential thermal analysis as part ofin situphase transition studies.


2006 ◽  
Vol 129 (2) ◽  
pp. 237-245 ◽  
Author(s):  
Gap-Yong Kim ◽  
Muammer Koç ◽  
Rhet Mayor ◽  
Jun Ni

One of the major challenges in simulation of semi-solid forming is characterizing the complex behavior of a material that consists of both solid and liquid phases. In this study, a material model for an A356 alloy in a semi-solid state has been developed for high solid fractions (>0.6) and implemented into a finite element simulation tool to investigate the micro-/mesoscale feature formation during the forming process. Compared to previous stress models, which are limited to expressing the stress dependency on only the strain rate and the temperature (or the solid fraction), the proposed stress model adds the capability of describing the semi-solid material behavior in terms of strain and structural evolution. The proposed stress model was able to explain the strain-softening behavior of the semi-solid material. Furthermore, a simulation model that includes the yield function, the flow rule, and the stress model has been developed and utilized to investigate the effects of various process parameters, including analysis type (isothermal vs nonisothermal), punch velocity, initial solid fraction, and workpiece shape (“flat” versus “tall”) on the micro-/mesofeature formation process.


2013 ◽  
Vol 765 ◽  
pp. 130-134 ◽  
Author(s):  
Deni Ferdian ◽  
Jacques Lacaze ◽  
Ibon Lizarralde ◽  
Andrea Niklas ◽  
Ana Isabel Fernandez-Calvo

In this present work, an assessment of eutectic modification based on thermal analysis was performed on modified A356 alloy. The effect of various cooling rates which were achieved by means of casting samples with various moduli in sand and metallic moulds was investigated. Cooling curves recorded from thermocouples inserted in the centre of the samples showed characteristic undercooling and recalescence associated with (Al)-Si eutectic modification. The results showed that cooling rate has a role in observed modification level. Furthermore, differential thermal analysis was included to determine the eutectic melting temperature.


2018 ◽  
Vol 134 (3) ◽  
pp. 1589-1597 ◽  
Author(s):  
Angel Sánchez Roca ◽  
Hipólito Domingo Carvajal Fals ◽  
Eugênio José Zoqui

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