Decomposition of the supersaturated solid solution in a rapidly solidified hypereutectic AlCu alloy

1994 ◽  
Vol 179-180 ◽  
pp. 327-333
Author(s):  
S.C. Gill ◽  
P.B. Prangnell
Keyword(s):  
Solid Solution ◽  
Supersaturated Solid Solution ◽  
Cu Alloy ◽  
Rapidly Solidified

Microstructures of Rapidly Solidified Hypereutectic Al-Si Alloy with Low-Titanium Content

2008 ◽  
Vol 575-578 ◽  
pp. 27-31
Author(s):  
Ai Qin Wang ◽  
Jing Pei Xie ◽  
Zhong Xia Liu ◽  
Ji Wen Li ◽  
Wen Yan Wang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Melt Spinning ◽  
Supersaturated Solid Solution ◽  
Primary Silicon ◽  
Titanium Content ◽  
Nucleation And Growth ◽  
Solidification Processing ◽  
Equilibrium Solidification ◽  
Rapidly Solidified ◽  
Morphology Characteristics

In the present work, rapidly solidified alloys strips with Al-0.24Ti and Al-21Si-0.24Ti(in wt.%) were prepared by single roller melt-spinning method. The microstructures, phase and morphology characteristics of the resultant strips were characterized by means of scanning electron microscopy (SEM),transmission electric microscopy (TEM) and XRD technique. The results show that the grains have been refined after rapid solidification processing, and the micro-nanocrystalline grain are formed. The morphology characteristics can be changed. The microstructures of Al-0.24Ti alloys strip are micro-nanostructure α-Al solid solutions which are similar with granular or nodular, the corresponding SAD pattern is rings, it presents characteristic of polycrystal; Compared with equilibrium solidification, the microstructures of hypereutectic Al-Si alloy are changed obviously. They are composed of primary micro-nanostructure α-Al supersaturated solid solution and nanocrystal granular (α+Si) eutectic which set in the supersaturated solid solution. The nucleation and growth of primary silicon are suppressed and primary silicon can not precipitate, meanwhile, α-Al phase is nucleated which prior to eutectic, therefore the microstructures become into the metastable state. The mechanism of the formation for microstructures of melt-spinning alloys has also been discussed.

Saturation magnetization in supersaturated solid solution of Co–Cu alloy

2009 ◽  
Vol 95 (16) ◽  
pp. 162502 ◽  
Author(s):  
Motohiro Yuasa ◽  
Kota Kajikawa ◽  
Masataka Hakamada ◽  
Mamoru Mabuchi
Keyword(s):  
Solid Solution ◽  
Saturation Magnetization ◽  
Supersaturated Solid Solution ◽  
Cu Alloy

Precipitation of Phases in Al-Mg-Si-Cu Alloy with Sc and Zr Additions during Heat Treatment

2007 ◽  
Vol 130 ◽  
pp. 163-166 ◽  
Author(s):  
Lidia Lityńska-Dobrzyńska
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Cooling Rate ◽  
Supersaturated Solid Solution ◽  
Ageing Temperature ◽  
Spherical Particles ◽  
Preliminary Heat Treatment ◽  
Complete Dissolution ◽  
Cu Alloy ◽  
Copper Mould

In the present work the sequence of phases in Al-1%Mg-0.6%Si-1%Cu (in wt %) alloys with 0.4%Sc and 0.2%Zr additions during heat treatment has been studied. The investigated alloys were cast into copper mould to ensure high cooling rate during solidification and the retention of Sc and Zr in the supersaturated solid solution. Two−step preliminary heat treatment was applied: the annealing at temperature 300°C or 350°C followed by quenching from 540°C to water. The precipitation of the Q′ and Al3Sc phases has been observed during the first step of annealing. The annealing at 540°C has led to complete dissolution of the Q′ particles and growth of the spherical particles of the Al3Sc phase. The increase of hardness during subsequent ageing at 165°C (typical ageing temperature of the 6xxx alloys) has been caused by the formation of needle-like Q′ phase which coexist with Al3Sc precipitates.

Structural Evolution of Al-Cr Alloy during Processing

2008 ◽  
Vol 138 ◽  
pp. 145-152 ◽  
Author(s):  
Dalibor Vojtěch ◽  
Alena Michalcová ◽  
Pavel Novák
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Phase Transformations ◽  
Elevated Temperatures ◽  
Supersaturated Solid Solution ◽  
Structural Evolution ◽  
Hot Extrusion ◽  
Light Components ◽  
Rapidly Solidified

Aluminium-chromium based alloys are promising candidates for manufacture of light components exposed to elevated temperatures. The work describes properties of Al-6.0wt.%Cr- 2.1wt.%Fe-0.5wt.%Ti alloy. The rapidly solidified powder was prepared by the pressure nitrogen melt atomization. The powder was then subject to heat treatment in order to investigate solid state phase transformations. Compaction of the powder was carried out by hot extrusion after preheating at 450 °C. Microstructure, phase composition and structural transformations on heat treatment were investigated in the as-atomized powder, as well as in the as-extruded alloy. It is found that metastable state of the rapidly solidified powder is characterized by presence of quasi-crystalline phases and supersaturated solid solution. Heating before and during the hot extrusion induces decomposition of the supersaturated solid solution and quasicrystalline to crystalline phase transformations. The hot extruded alloy has a refined recrystallized structure that remains very stable aven after long-term annealing at 400 °C. Mechanical properties of the extruded alloy are discussed in terms of strengthening mechanisms.

Nanometer Stripe Microstructure of Supersaturated Solid Solution in Fe-Cu Alloy

2007 ◽  
Vol 14 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Hui-ping Ren ◽  
Hai-yan Wang ◽  
Zong-chang Liu ◽  
Zhi-guo An
Keyword(s):  
Solid Solution ◽  
Supersaturated Solid Solution ◽  
Cu Alloy

scholarly journals Diffusionless (chemically partitionless) crystallization and subsequent decomposition of supersaturated solid solutions in Sn–Bi eutectic alloy

2019 ◽  
Vol 377 (2143) ◽  
pp. 20180204 ◽  
Author(s):  
Olga V. Gusakova ◽  
Peter K. Galenko ◽  
Vasiliy G. Shepelevich ◽  
Dmitri V. Alexandrov ◽  
Markus Rettenmayr
Keyword(s):  
Solid Solution ◽  
Eutectic Alloy ◽  
Supersaturated Solid Solution ◽  
Eutectic Growth ◽  
Rapid Quenching ◽  
Cooling Rates ◽  
Internal Structures ◽  
Supersaturated Solid Solutions ◽  
Rapidly Solidified ◽  
Subsequent Decomposition

Results of a study on microstructural evolution of eutectic Sn-57 wt.% Bi processed with cooling rates of 10 −2 , 1 K s −1 and approximately 10 5  K s −1 are presented. In order to distinguish different mechanisms of microstructure formation, a comparison with microstructures of different hypoeutectic alloys with compositions down to below the maximum solubility of Bi in Sn–Bi is undertaken. It is found that at the cooling rates of 10 −2 and 1 K s −1 , coupled eutectic growth occurs, leading to lamellar structures with different length scales. At the rapid quenching rates of approximately 10 5  K s −1 , structure formation in the eutectic alloy is qualitatively different. Partitionless solidification resulting in a supersaturated solid solution with the initial composition is observed in both eutectic and hypoeutectic alloys. It is shown that the observed microstructure of the rapidly solidified alloys forms by the decomposition of the supersaturated solid solution. This article is part of the theme issue ‘Heterogeneous materials: metastable and non-ergodic internal structures’.

Direct Observation of Monolayer Zones in Al-wt 4% Cu

1990 ◽  
Vol 48 (1) ◽  
pp. 14-15
Author(s):  
B. Jouffrey ◽  
D. Dorignac ◽  
A. Bourret
Keyword(s):  
Solid Solution ◽  
Synchrotron Radiation ◽  
Direct Observation ◽  
Supersaturated Solid Solution ◽  
Original Model ◽  
X Ray ◽  
Image Position

Since the early works on GP zones and the model independently proposed by Preston and Guinier on the first steps of precipitation in supersaturated solid solution of aluminium containing a few percent of copper, many works have been performed to understand the structure of different stages in the sequence of precipitation.The scheme which is generally admitted can be drawn from a work by Phillips.In their original model Guinier and Preston analysed a GP zone as composed of a single (100) copperrich plane surrounded by aluminum atomic planes with a slightly shorter distance from the original plane than in the solid solution.From X-ray measurements it has also been shown that GP1 zones were not only copper monolayer zones. They could be up to a few atomic planes thick. Different models were proposed by Guinier, Gerold, Toman. Using synchrotron radiation, proposals have been recently made.

Metallographic analysis of M2 high speed steel granules

2019 ◽  
pp. 78-85
Author(s):  
L. E. Afanasieva
Keyword(s):  
Solid Solution ◽  
Cellular Structure ◽  
High Speed ◽  
Solution Structure ◽  
Supersaturated Solid Solution ◽  
High Speed Steel ◽  
Metallographic Analysis ◽  
M2 High Speed Steel ◽  
Melt Composition

The article is devoted to the metallographic analysis of the M2 high-speed steel granules. The study is based on the investigation of the microstructure of the M2 high-speed steel granules obtained by melt atomization. It is demonstrated that granules of similar size can harden both by chemically separating and chemically non-separating mechanism. These last ones have supersaturated solid solution structure of the liquid melt composition, a dispersed dendritic-cellular structure and an increased microhardness HV = 10267±201 MPa.

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