The effect of na and Sr modification on surface tension and volumetric shrinkage of A356 alloy and their influence on porosity formation

1993 ◽  
Vol 24 (6) ◽  
pp. 1055-1063 ◽  
Author(s):  
D. Emadi ◽  
J. E. Gruzleski ◽  
J. M. Toguri
Keyword(s):  
Surface Tension ◽  
A356 Alloy ◽  
Volumetric Shrinkage ◽  
Porosity Formation ◽  
Sr Modification

scholarly journals The Relationship between Residual Amount of Sr and Morphology of Eutectic Si Phase in A356 Alloy

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3222 ◽  
Author(s):  
Wenda Zhang ◽  
Shixuan Ma ◽  
Zhenhua Wei ◽  
Peikang Bai
Keyword(s):  
A356 Alloy ◽  
Sand Mold ◽  
Sr Modification ◽  
Treatment Processes ◽  
Modification Effect ◽  
Residual Amount ◽  
Eutectic Si ◽  
The Relationship ◽  
Modification Treatment ◽  
Alloy Cast

This paper studied the relationship between the residual amount of Sr and the morphology of the eutectic Si phase in A356 obtained through different modification treatment processes; additionally, the cooling rates of molds were studied. The eutectic Si phase revealed a satisfactory modification effect at residual Sr amounts above 0.01 wt % in A356 alloys cast using an iron mould. Complete modification of the eutectic Si phase could be achieved at a Sr additive amount 0.03 wt % in an A356 melt. The addition of higher amounts of Sr (~0.04–0.06 wt %) did not improve the modification effect. With the addition of 0.06 wt % Sr into A356 alloy melt and holding at 750 °C, the anti-fading capacity of Sr modification effect could be sustained for 120 minutes. More Sr is needed to obtain a good modification of eutectic Si for an A356 alloy cast using a sand mold.

Porosity Formation after the Irradiation Termination of Laser

2013 ◽  
Vol 800 ◽  
pp. 201-204
Author(s):  
Wang Hong ◽  
Ling Yun Wang ◽  
Ri Sheng Li
Keyword(s):  
Surface Tension ◽  
Laser Welding ◽  
Continuous Wave ◽  
Laser Beams ◽  
Formation Mechanisms ◽  
Volume Of Fluid Method ◽  
Porosity Formation ◽  
Mode Laser ◽  
Melt Pool ◽  
Solidification Processes

Porosity is formed because of the keyhole collapse. The porosity formation is associated with the melt pool dynamics, the keyhole collapse and solidification processes. The objective of the paper is t to investigate porosity formation mechanisms and fluid flow in the melt pool using the volume of fluid method. The results indicate that the formation of porosity in continuous wave keyhole mode laser welding is associated to keyhole collapse, backfilling of liquid metal close the gas exit of the laser welding keyhole, surface tension of the gas/liquid interface play an important role in the backfilling downward to the keyhole right after laser beams left.Keywords: porosity; keyhole; collapse; welding; model

Effect of Sr addition on porosity formation in directionally solidified A356 alloy

2013 ◽  
Vol 26 (4) ◽  
pp. 201-208 ◽  
Author(s):  
H C Liao ◽  
W Song ◽  
Q G Wang ◽  
L Zhao ◽  
R Fan ◽  
...  
Keyword(s):  
A356 Alloy ◽  
Directionally Solidified ◽  
Porosity Formation

Effect of Strontium Modification on Porosity Formation in A356 Alloy

2019 ◽  
Vol 13 (4) ◽  
pp. 944-952 ◽  
Author(s):  
Qian Wang ◽  
Qitang Hao ◽  
Wentao Yu
Keyword(s):  
A356 Alloy ◽  
Porosity Formation

Effect of Rare Earth Metals on Porosity Formation in A356 Alloy

2017 ◽  
Vol 12 (2) ◽  
pp. 251-265 ◽  
Author(s):  
M. G. Mahmoud ◽  
E. M. Elgallad ◽  
M. F. Ibrahim ◽  
F. H. Samuel
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
A356 Alloy ◽  
Porosity Formation

Effects of Casting Variables on Soundness of A356 Alloy Products in Rheo-Diecasting

2006 ◽  
Vol 116-117 ◽  
pp. 128-131 ◽  
Author(s):  
J.M. Kim ◽  
J.G. Sim ◽  
J.Y. Moon ◽  
M.S. Kim ◽  
K.M. Yoon ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Casting Defects ◽  
Sr Modification ◽  
Shrinkage Defects ◽  
Filling Pattern ◽  
Die Temperature ◽  
Silicon Particles ◽  
Cast Products

The effects of die temperature and plunger velocity on the soundness of semisolid cast products were investigated in regards to the flow behavior of the slurry of A356 alloy in the H-NCM rheo-diecasting process. The sound cast was obtained with the die-temperatures of above 220 . The sudden changes of casting velocity resulted in irregular microstructures with micro-porosity and shrinkage defects due to turbulent filling pattern. The high casting velocity at the end of filling has no effect on the castability and the formation of casting defects in H-NCM(Hong-NanoCasting method). The Sr modification provides much finer and spheriodized eutectic silicon particles.

Electromagnetic stirring and Sr modification in A356 alloy

2001 ◽  
Vol 111 (1-3) ◽  
pp. 69-73 ◽  
Author(s):  
B.I. Jung ◽  
C.H. Jung ◽  
T.K. Han ◽  
Y.H. Kim
Keyword(s):  
A356 Alloy ◽  
Electromagnetic Stirring ◽  
Sr Modification

The role of the pressure index in porosity formation in A356 alloy castings

Cast Metals ◽  
1995 ◽  
Vol 7 (4) ◽  
pp. 219-225 ◽  
Author(s):  
Sen-Tien Kao ◽  
Edward Chang
Keyword(s):  
A356 Alloy ◽  
Porosity Formation ◽  
Pressure Index ◽  
Alloy Castings

scholarly journals Effect of Solidification Rate and Rare Earth Metal Addition on the Microstructural Characteristics and Porosity Formation in A356 Alloy

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
M. G. Mahmoud ◽  
A. M. Samuel ◽  
H. W. Doty ◽  
S. Valtierra ◽  
F. H. Samuel
Keyword(s):  
Rare Earth ◽  
Solidification Rate ◽  
A356 Alloy ◽  
Earth Metal ◽  
Atomic Radius ◽  
Shrinkage Porosity ◽  
Minor Effect ◽  
Porosity Formation ◽  
Agent Interaction ◽  
Eutectic Si

The present study was performed on A356 alloy with the main aim of investigating the effects of La and Ce additions to 356 alloys (with and without 100 ppm Sr) on the microstructure and porosity formation in these alloys. Measured amounts of La, Ce, and Sr were added to the molten alloy. The results showed that, in the absence of Sr, addition of La and Ce leads to an increase in the nucleation temperature of the α-Al dendritic network with a decrease in the temperature of the eutectic Si precipitation, resulting in increasing the freezing range. Addition of 100 ppm Sr results in neutralizing these effects. The presence of La or Ce in the casting has a minor effect on eutectic Si modification, in spite of the observed depression in the eutectic temperature. It should be noted that Ce is more effective than La as an alternate modifying agent. According to the atomic radius ratio, rLa/rSi is 1.604 and rCe/rSi is 1.559, theoretically, which shows that Ce is relatively more effective than La. The present findings confirm that Sr is the most dominating modification agent. Interaction between rare earth (RE) metals and Sr would reduce the effectiveness of Sr. Although modification with Sr causes the formation of shrinkage porosity, it also reacts with RE-rich intermetallics, resulting in their fragmentation.

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