Effect of cooling rate on microstructure and high temperature stability of rapidly solidified Al-Fe-V-Si alloys

Recently, AI-Fe-V-Si alloys have received more attention owing to their high temperature stability associated with vanadium rich precipitates and silicides. In this work, a series of alloys was prepared and processed by melt spinning and gas atomisation to observe the effect of solidification rate on crystal structures existing in both as cast and heat treated conditions. This study covers their microstructural examination and crystallography. The composition of these alloys was Al-(6.8-7.8)Fe-( 1.0-3)V-(1.6-2.2)Si and the ribbons and powders produced were examined by SEM and TEM. Investigations revealed that most of the rapidly solidified ribbons and powders consisted of a cellular structure with cubic spherical dispersoids and quasicrystalline i phase spheroids. The proportions of these phases were found to be dependent on section thickness and cooling rate of the products. More i phase spheroids were observed in sections of melt spun ribbons and coarse powders. After heat treatment at 300, 400, and 500 degrees C, the sizes of these dispersoids were detected to be two or three times the original as cast sizes. PM/0803 (C) 1999 IoM Communications Ltd.


Effect of spraying rate on microstructure of spray deposited Al-Fe-V-Si alloy
Kalkanlı, Ali (Informa UK Limited, 2003-12-01)
In this study gas atomisation and spray deposition of a series of AlFeVSi alloys were carried out. Traces of transient liquid were observed as lamellar structure in the middle of the specimen. The heat transfer conditions of this structure were modelled by finite difference calculation. Metallographic specimens for optical microscopy were prepared from the preforms formed in these processes. Optical microscopy showed the presence of dispersoids in the specimens. The dispersoids were characterised as AlFeVSi...
Effect of magnetic field and gamma irradiation on the electrical properties and structure of the Tl-based ceramic superconductors
Ozkan, H; Hasanlı, Nızamı; Kayed, T (IOP Publishing, 2000-02-01)
The voltage-current (V-I) characteristics, critical temperatures and the critical currents of Tl2Ba2CaCu2O8 (Tl-2212) and Tl2Ba2Ca2Cu3O10 (Tl-2223) ceramic superconductors were studied in magnetic fields up to 80 mT after several gamma irradiations up to 100 MR. The effect of gamma irradiation on the structure of these materials has also been studied. The normal state resistance increases by 20-30% with gamma irradiation, most of the changes taking place in low gamma doses up to 10 MR. The critical temperat...
Effect of tube spinning and subsequent heat treatments on strength, microstructure and residual stress state of AISI/SAE type 4140 steel
Gür, Cemil Hakan (Informa UK Limited, 2003-11-01)
In the present study, the effects of deformation percentage (23, 30, 50 and 66%) and subsequent stress relief and tempering heat treatments on the mechanical properties, residual stress state and microstructure of AISI/SAE type 4140 steel tubes manufactured by forward spinning were evaluated. Mechanical properties were determined by means of hardness and tensile tests. The tangential component of the surface residual stresses was determined by a slitting method. Plastic deformation of the metal during spinn...
Effect of (Mo, W) substitution for Nb on glass forming ability and magnetic properties of Fe-Co-based bulk amorphous alloys fabricated by centrifugal casting
Kucuk, Ilker; Aykol, Muratahan; Uzun, Orhan; Yıldırım, Mehmet; Kabaer, Mehmet; Duman, Nagehan; Yilmaz, Fikret; Erturk, Kadir; Akdeniz, Mahmut Vedat; Mehrabov, Amdulla (Elsevier BV, 2011-02-03)
In this study, effects of simultaneous Mo and W substitution for Nb additions on the stability and magnetic properties of Fe-Co-based bulk metallic glass (BMG) alloys fabricated by centrifugal casting are investigated. The saturation magnetization (J(s)) and coercivity (H(c)) for the as-cast Fe(36)CO(36)B(19.2)Si(4.8)X(4) (X = Nb or Mo(0.5)W(0.5)) BMG alloys and melt-spun Fe(36)Co(36)B(19.2)Si(4.8)Mo(2)W(2) were in the range of 1.02-1.57T and 11.13-1685 A/m, respectively. The Fe(36)Co(36)B(19.2)Si(4.8)X(4) ...
Effect of lithium doping on the properties of Tl-based superconductors
Kayed, TS; Ozkan, H; Hasanlı, Nızamı (IOP Publishing, 2001-09-01)
The effects of lithium doping on the formation and properties of the T1-based superconductors have been studied. Lithium atoms up to around 3 mol.% have been added to the oxides of nominal composition Tl1.8Ba2Ca2.2Cu3Ox, and the usual solid-state reaction method has been applied. Lithium additions in the range 0.23-0.29 mol.% increase the fraction of the Tl-2223 phase and significantly improve the critical temperature of the samples. Higher amounts of lithium additions diminish the Tl-2223 phase, reduce the...
Citation Formats
A. Kalkanlı, “Effect of cooling rate on microstructure and high temperature stability of rapidly solidified Al-Fe-V-Si alloys,” POWDER METALLURGY, pp. 359–365, 1999, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35960.