Microstructure Simulation of Die Casting AZ91D Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 109-112
Author(s):  
Z.Y. Liu ◽  
Qing Yan Xu ◽  
Bai Cheng Liu

Physical and mathematical models of microstructure evolution during the solidification process of die casting AZ91D alloy were investigated in this paper. Coupled with solute concentration, a modified three-dimensional cellular automaton (CA) model was proposed. Considering the solute enrichment and the formation of eutectic microstructure, these models can reproduce the whole microstructure evolution process of Mg alloy, from the formation of primary phase to the eutectic transformation. The microstructure of the AZ91D alloy cylinder head cover die casting was simulated with the proposed models. The simulated results are in agreement with the experimental.

2011 ◽  
Vol 311-313 ◽  
pp. 600-608
Author(s):  
Zhao Chen ◽  
Xiao Li Wen ◽  
Chang Le Chen

Solidification behaviour of Pb-Bi alloys under rotating magnetic field (RMF) was investigated experimentally to understand the effect of the frequency of RMF on the nucleation and growth behaviour. It was found that, as the increase of the rotating frequency, the grains are fragmented and refined gradually until a transition from columnar to equiaxed microstructures happens at a rotating frequency of 40 Hz. Moreover, the Bi concentration of the primary phase decreases and macrosegregation is eliminated effectively with RMF. These are due to the effect of RMF on the nucleation, growth and fluid flow in the solidification process.


2008 ◽  
Vol 575-578 ◽  
pp. 98-103
Author(s):  
Wen Yan Wang ◽  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Ai Qin Wang ◽  
Luo Li Li ◽  
...  

The solidification process, the formation mechanism and distribution law of microporosity of the ball milling machine head cover made by SVEDALA corporation of USA were simulated by computer. The Solidworks software was used to generate three-dimensional model of cast parts and the Hua-casting software was employed to simulate the casting process. The simulated results show that significant microporosity was found in the middle of two casting heads and at the place of gudgeon journal because of insufficient chilling degree. The processing rationality was judged through the computer-aided technology, by which some drawbacks of the traditional process were overcome and the process design quality was improved.


2018 ◽  
Vol 913 ◽  
pp. 212-219 ◽  
Author(s):  
Bing Wu ◽  
Ao Lei Jiang ◽  
Hao Lu ◽  
Hong Liang Zheng ◽  
Xue Lei Tian

A mathematical physical model of microstructure evolution in Al-Si eutectic solidification process based on cellular automaton (CA) model was developed. Before the establishment of the model, the relevant near-eutectic experiments were carried out to analyze the effect of cooling rates measured by temperature curves on the eutectic structure which was observed through optical microscope (OM) and scanning electron microscope (SEM). Then a multiphase nucleation-growth CA model was applied to simulate the Al-Si irregular eutectic structure. The model adopted an alternative nucleation mechanism to investigate the influence of the critical nucleation value associated with solute concentration during solidification process. The growth kinetics took into account the solute and thermal field. According to the crystal structure of nonfaceted eutectic Al and faceted eutectic Si, different capturing rules were employed to calculate the growth of eutectic. In addition, the model was also used to research the irregular eutectic growth under different undercooling conditions. The results revealed that smaller critical nucleation value (absolute value) or higher eutectic undercooling tended to get a more refined eutectic microstructure. By compared with experimental results, it is indicated that the microstructure evolution of Al-Si eutectic growth can be reproduced quantitatively by numerical simulation with this model.


2005 ◽  
Vol 488-489 ◽  
pp. 279-282 ◽  
Author(s):  
Hai Feng Liu ◽  
Guodong Tong ◽  
Jun Hou

A series of high temperature creep resistant magnesium alloys for die casting based on AZ91 were successfully developed by the addition of Rare Earth, and Calcium. The original target of magnesium alloy development was aimed at cylinder head cover of high power diesel engine, and tried to satisfy the temperature demands of gear-box house. The tensile property at room temperature, creep behavior at 150ı,and analysis of microstructure were discussed in this paper. The results showed that these alloys has potential for die casting to produce power-train parts, and greatly decrease the weigh of parts.


1994 ◽  
Vol 361 ◽  
Author(s):  
V.A. Alyoshin ◽  
E.V. Sviridov ◽  
V.I.M. Hukhortov ◽  
I.H. Zakharchenko ◽  
V.P. Dudkevich

ABSTRACTSurface and cross-section relief evolution of ferroelectric epitaxial (Ba,Sr)TiO3 films rf-sputtered on (001) HgO crystal cle-avage surface versus the oxygen worKing gas pressure P and subst-rate temperature T were studied. Specific features of both three-dimensional and two-dimensional epitaxy mechanisms corresponding to various deposition conditions were revealed. Difference between low and high P-T-value 3D epitaxy was established. The deposition of films with mirror-smooth surfaces and perfect interfaces is shown to be possible.


2004 ◽  
Vol 120 ◽  
pp. 225-230
Author(s):  
P. Mukhopadhyay ◽  
M. Loeck ◽  
G. Gottstein

A more refined 3D cellular Automata (CA) algorithm has been developed which has increased the resolution of the space and reduced the computation time and can take care of the complexity of recrystallization process through physically based solutions. This model includes recovery, condition for nucleation and orientation dependent variable nuclei growth as a process of primary static recrystallization. Incorporation of microchemistry effects makes this model suitable for simulating recrystallization behaviour in terms of texture, kinetics and microstructure of different alloys. The model is flexible to couple up with other simulation programs on a common database.


2011 ◽  
Vol 50 (12) ◽  
pp. 3334-3341 ◽  
Author(s):  
Song Hao ◽  
Chuanzhen Huang ◽  
Bin Zou ◽  
Jun Wang ◽  
Hanlian Liu ◽  
...  

2018 ◽  
Vol 925 ◽  
pp. 90-97 ◽  
Author(s):  
Juan Carlos Hernando ◽  
Attila Diószegi

It is widely accepted that in most commercial hypoeutectic alloys, both static mechanical properties and feeding characteristics during solidification, are extremely linked to the coarseness of the primary phase. It is therefore of critical importance to provide tools to control and predict the coarsening process of the dendritic phase present in hypoeutectic melts. The characterization of the primary phase, a product of the primary solidification, has traditionally been neglected when compared to the eutectic solidification characterization in cast iron investigations. This work presents the morphological evolution of the primary austenite present in a hypoeutectic compacted graphite cast iron (CGI) under isothermal conditions. To that purpose, a base spheroidal graphite cast iron (SGI) material with high Mg content is re-melted in a controlled atmosphere and reversed into a CGI melt by controlling the Mg fading. An experimental isothermal profile is applied to the solidification process of the experimental alloy to promote an isothermal coarsening process of the primary austenite dendrite network during solid and liquid coexistence. Through interrupted solidification experiments, the primary austenite is preserved and observed at room temperature. By application of stereological relations, the primary phase and its isothermal coarsening process are characterized as a function of the coarsening time applied. The microstructural evolution observed in the primary austenite in CGI and the measured morphological parameters show a similar trend to that observed for lamellar graphite cast iron (LGI) in previous investigations. The modulus of the primary austenite, Mγ, and the nearest distance between the centre of gravity of neighbouring austenite particles, Dγ, followed a linear relation with the cube root of coarsening time.


2020 ◽  
Vol 53 (2) ◽  
pp. 349-359 ◽  
Author(s):  
A. Trenkle ◽  
M. Syha ◽  
W. Rheinheimer ◽  
P.G. Callahan ◽  
L. Nguyen ◽  
...  

Nondestructive X-ray diffraction contrast tomography imaging was used to characterize the microstructure evolution in a polycrystalline bulk strontium titanate specimen. Simultaneous acquisition of diffraction and absorption information allows for the reconstruction of shape and orientation of more than 800 grains in the specimen as well as porosity. Three-dimensional microstructure reconstructions of two coarsening states of the same specimen are presented alongside a detailed exploration of the crystallographic, topological and morphological characteristics of the evolving microstructure. The overall analysis of the 3D structure shows a clear signature of the grain boundary anisotropy, which can be correlated to surface energy anisotropy: the grain boundary plane distribution function shows an excess of 〈100〉-oriented interfaces with respect to a random structure. The results are discussed in the context of interface property anisotropy effects.


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