A one phase thermomechanical model for the numerical simulation of semi-solid material behavior. Application to thixoforming

2014 ◽  
Vol 58 ◽  
pp. 120-153 ◽  
Author(s):  
R. Koeune ◽  
J.P. Ponthot
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.


2017 ◽  
Vol 322 ◽  
pp. 301-312 ◽  
Author(s):  
Susumu Yamashita ◽  
Takuya Ina ◽  
Yasuhiro Idomura ◽  
Hiroyuki Yoshida

Author(s):  
M Ghaffarpour ◽  
D Akbari ◽  
H Moslemi Naeini

In this paper, the effects of the joint type on the driven-out bead of the roll-formed pipes, welded by high-frequency induction welding process are studied. The main goal is to predict and reduce the volume of the bead driven out in the weld seam. Moreover, it aims to move the semi-solid bead during welding to the outer diameter of the pipe. This study has two prior aims: to produce a defect-free joint and to improve the mechanical and metallurgical properties. In order to optimize the weld joint, various joint types have been investigated by experimental tests and simulation. Lastly, destructive tests were used to determine if the desired mechanical properties of the weld joint were obtained. The metallurgical properties and the derivation of the semi-solid material in the weld zone have both been investigated in terms of microstructure. According to the results, the proper joint type improves the mechanical properties by 5% and reduces the volume of the weld bead about 45%.


2020 ◽  
Vol 13 (10) ◽  
pp. 1688-1702
Author(s):  
Lei Xu ◽  
Ximena Yepez ◽  
Bruce Applegate ◽  
Kevin M Keener ◽  
Bernard Tao ◽  
...  

2008 ◽  
Vol 18 (3) ◽  
pp. 682-685 ◽  
Author(s):  
Yue-long BAI ◽  
Wei-min MAO ◽  
Jun XU ◽  
Hong XU ◽  
Hua HOU

2012 ◽  
Vol 192-193 ◽  
pp. 293-298 ◽  
Author(s):  
Fan Zhang ◽  
Nan Nan Song ◽  
Jun Zhang ◽  
Yong Lin Kang ◽  
Qiang Zhu

According to semi-solid slurry rheological behavior, an apparent viscosity model of A356 alloy developed based on the Carreau model was established to simulate filling process of rheo-diecasting about automobile shock absorber parts and to compare with conventional liquid filling process. Numerical simulation results showed that the filling process of rheo-diecasting was smooth but difficult to splash, which reduced the tendency of the alloy oxidation and inclusion. Meanwhile, a certain percentage of the primary solid particles precipitated before filling and solidification shrinkage of semi-solid slurry were small. This benefited to reduce or eliminate shrinkage defects of the castings. Compared with conventional liquid die casting process, rheo-diecasting process had unique advantages in reducing the internal defects and improving mechanical properties of castings.


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