scholarly journals Lamellar Spacings Determined by Solid-Liquid Interfacial Morphology of Unidirectionally Solidified Al-Base Binary Eutectic Alloys

1993 ◽  
Vol 57 (9) ◽  
pp. 1054-1063
Author(s):  
Kazumitsu Shinohara ◽  
Toshihiro Seo ◽  
Takashi Naohara ◽  
Noriaki Sugamoto ◽  
Yuji Tadokoro
Keyword(s):  
Eutectic Alloys ◽  
Interfacial Morphology ◽  
Binary Eutectic ◽  
Solid Liquid

scholarly journals Back-Diffusion In Crystal Growth. Eutectics

2015 ◽  
Vol 60 (3) ◽  
pp. 2403-2407 ◽  
Author(s):  
W. Wołczyński
Keyword(s):  
Differential Equation ◽  
Crystal Growth ◽  
Current Model ◽  
Solute Segregation ◽  
Solidification Path ◽  
Back Diffusion ◽  
Eutectic Alloys ◽  
Equilibrium Solidification ◽  
Solid Liquid ◽  
Non Equilibrium

Abstract Solute segregation/redistribution model for some eutectic alloys is presented. The differential equation for the solute micro-segregation during solidification accompanied by the back-diffusion is formulated. The solution to this equation results in the definitions of: solidification path, solid/liquid (s/l) interface path and redistribution path. An equation for the estimation of the amount of equilibrium and non-equilibrium precipitates is also delivered. It is proved that the current model is universal one. Thus, the model reduces perfectly, mathematically to both description of diffusion-less solidification and model of equilibrium solidification.

scholarly journals Morphological Development of Sub-Grain Cellular/Bands Microstructures in Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1204 ◽  
Author(s):  
Xihe Liu ◽  
Xin Zhou ◽  
Ben Xu ◽  
Jing Ma ◽  
Congcong Zhao ◽  
...  
Keyword(s):  
Surface Tension ◽  
Selective Laser Melting ◽  
Single Layer ◽  
Liquid Interface ◽  
Morphological Development ◽  
Eutectic Alloys ◽  
Laser Melting ◽  
Submicron Scale ◽  
Solid Liquid Interface ◽  
Solid Liquid

In this paper, single-layer and bulk 316 L selective laser melting (SLM) experiments were conducted, fine submicron-scale geometric symmetrical cellular (hexagonal, pentagonal and square), elongated cellular and bands solidification morphologies were found in the laser-melt top surface. Meanwhile, morphological developed sub-grain patterns with quasi-hexagonal cellular, elongated cellular and bands structures (size ~1 μm) coexisting inside one single macro-solidified grain were also identified. This demonstrated the transitions from quasi-hexagonal-cells to elongated cells/bands, and transitions reverse, occurred in the whole bulk under some circumstances during SLM. Based on the experimental realities, these morphologies are formed by the local convection and Bénard instabilities in front of the solid/liquid interface (so-called mushy zones) affected by intricate temperature and surface tension gradients. Quasi-hexagonal cellular convective fields are then superimposed on macro-grain solidification to form the sub-grain patterns and micro-segregations. This explanation seems reasonable and is unifying as it can be expanded to other eutectic alloys with face center cubic (FCC) prevenient phase prepared by SLM, e.g., the Al-Si and Co-Cr-Mo systems.

Crystallographic orientation of primary and eutectic phases in a hypoeutectic Mn–Sb alloy induced by solidification in high magnetic fields

2019 ◽  
Vol 52 (5) ◽  
pp. 945-950 ◽  
Author(s):  
Shulin Dong ◽  
Tie Liu ◽  
Meng Dong ◽  
Shuang Wang ◽  
Wen Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Crystallographic Orientation ◽  
Field Direction ◽  
High Magnetic Fields ◽  
Magnetic Field Direction ◽  
Eutectic Alloys ◽  
Random Orientation ◽  
Binary Eutectic ◽  
The Magnetic Field

This paper investigates how applying high magnetic fields influences the crystallographic orientations of the primary and eutectic phases, and their relationship, in a binary eutectic alloy. At 0 T, the primary MnSb phase in hypoeutectic Mn–Sb showed a random orientation, but at 3, 6, 9 and 11.5 T, its c axis was perpendicular to the magnetic field direction. In all cases, the eutectic MnSb phases showed the same orientations as their neighboring primary MnSb phase, on which they nucleated and grew. With high magnetic fields, the c axes of the eutectic and primary MnSb phases were oriented perpendicular to the magnetic field direction. The results show that applying a high magnetic field during solidification is a way of controlling the crystallographic orientation of both the primary and the eutectic phases in eutectic alloys.

scholarly journals Interactions of Cu-substrates with titanium-alloyed Sn-Zn solders

2006 ◽  
Vol 42 (1) ◽  
pp. 45-56 ◽  
Author(s):  
D. Soares ◽  
J. Barbosa ◽  
C. Vilarinho
Keyword(s):  
Thermal Analyses ◽  
Copper Substrate ◽  
Reaction Times ◽  
Chemical Compositions ◽  
Eutectic Alloys ◽  
Diffusion Couples ◽  
Phase Layer ◽  
Cu Substrates ◽  
Series Of Experiments ◽  
Solid Liquid

The interactions of copper substrate with titanium-alloyed Sn-Zn eutectic solders have been studied. Two series of experiments have been performed. The first one consisted in differential thermal analyses of Sn-Zn nearly eutectic alloys containing from 1.3 to 2.2 wt. % Ti. Diffusion couples consisted of Cu-wires and Sn-Zn-Ti liquid solders, produced at 250 and 275 OC have been prepared in the second series,. The contact times were up to 3600 s. The contact zones have been characterized by optical and scanning electron microscope. Two layers have been found along the interfaces solid/liquid. The first and the second layers are identical, respectively, with ? and ? phases of the Cu-Zn system. No changes of the chemical compositions were detected for the tested temperatures and reaction times. Continuous parabolic growth of the total diffusion zone thickness with the time of diffusion is observed. The growth is due mainly to one the formed layers (? ) while the thickness of the ?-phase layer, stays almost constant for all tested diffusion times and temperatures.

scholarly journals Hopeful high-strength casting alloys based on Al―Mg―Ge(Si) ternary systems

2020 ◽  
Vol 2020 (01) ◽  
pp. 55-66
Author(s):  
N. P. Korzhova ◽  
◽  
T. M. Legka ◽  
Y. V. Milman ◽  
K. E. Grinkevich ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Cast Alloy ◽  
High Strength ◽  
Ternary Systems ◽  
Eutectic Type ◽  
Eutectic Alloys ◽  
Binary Eutectic ◽  
Casting Aluminum ◽  
Multicomponent Eutectic

The relative analysis of phase equilibria in the Al-corner of the ternary phase diagrams of Al―Mg―Ge(Si) systems is carried out. Both systems are characterized by the presence of a quasi-binary cross-section of the eutectic type, which is shifted towards Mg-enriched alloys, and sufficiently width range existence of the univariant eutectic transformation L-Al + Mg2Ge(Si). The melting point of quasi-binary eutectic (-Al + Mg2Ge) in the Al―Mg–Ge system and (-Al + Mg2Si) in the Al―Mg―Si is 629 °С and 597 °С, respectively, and the content of the strengthening phase ((Mg2Ge or Mg2Si) in eutectics is 7% (vol.) и 13% (vol.). The properties of non-alloyed alloys with different volume content of eutectic are investigated and the basic compositions of alloys with the optimal strength/ductility ratio for subsequent doping are selected as well. Taking into account the coordinates of the corresponding eutectic transformations, the doping system with the participation of Zn, Cu and other elements is determined. The heat treatment regimes for multicomponent eutectic alloys were selected, to ensure precipitation of Zn(Cu)-nanoparticles that strengthen matrix solid solution. It was shown that according to the level of mechanical properties, these alloys belong to high-strength alloys with property ranges: -Al + Mg2Ge) ― В = 470―590 МPа, 0,2 = 350―520 МPа, = 8,0―15,5%; -Al + Mg2Si) ― В = 400―560 МPа, 0,2 = = 430―520 МPа, = 2,3–-4,5%. Using a complex U-like Nechenji―Kuptsov test, casting properties were determined and it was shown that the fluidity of (-Al + Mg2Si) alloy was 1,3 times higher than that of the AK7ch cast alloy. In terms of the combination of mechanical and casting properties, the new multicomponent eutectic alloys based on the Al―Mg―Ge(Si) ternary systems are superior to the best modern industrial casting aluminum alloys. Keywords: casting aluminum alloys, ternary Al―Mg―Ge(Si) systems, eutectic alloys, alloying, microstructure, mechanical properties, fluidity.

Effect of High Rotating Magnetic Field on the Solidified Structure of Al–7wt.%Si–1wt.%Fe Alloy

2013 ◽  
Vol 752 ◽  
pp. 57-65 ◽  
Author(s):  
András Roósz ◽  
Jenő Kovács ◽  
Arnold Rónaföldi ◽  
Árpád Kovács
Keyword(s):  
Magnetic Field ◽  
Interface Velocity ◽  
Longitudinal Section ◽  
Rotating Magnetic Field ◽  
Christmas Tree ◽  
Binary Eutectic ◽  
Si Content ◽  
The One ◽  
Solid Liquid Interface ◽  
Solid Liquid

Al–7wt.-% Si–1wt.-% Fe alloy was solidified unidirectionally in the Crystallizer with High Rotating Magnetic Field (CHRMF). The diameter of sample was 8 mm and its length was 120 mm. The parameters of solidification were as follows: solid/liquid interface velocity ~0.082 mm/s, temperature gradient 7+/-1 K/mm, magnetic induction 0 and 150 mT, frequency of magnetic field 0 and 50 Hz. The structure solidified without rotating magnetic field (RMF) showed a homogeneous, columnar dendritic one. The structure solidified by using magnetic stirring showed a dual periodicity. On the one hand, the branches of the “Christmas tree”-like structure known from the earlier experiments contained Al+Si binary eutectic. On the other hand, bands with higher Fe- and Si-content formed in the sample, which were at a larger distance from each other than the branches of the “Christmas tree” structure. The developed microstructure was analyzed by SEM with EDS. The average Si- and Fe-concentrations were measured on the longitudinal section at given places along the length of sample. Furthermore the Si- and the Fe-concentrations close to the bands and among the bands as well as the composition of the compound phases were determined.

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