Rapid quenching of semisolid Ti-Cu alloys: Insights into globular microstructure formation and coarsening

Abstract Semi-solid processing (SSP) belongs to advance method of forming metal alloys in the solidus-liquidus range. Such technology requires a fine globular microstructure in a semi-solid range, which can be produced by numerous methods. The present paper focuses on two methods of preparation of a globular microstructure in X210CrW12 tool steel as a possible way of preparation of feedstock for thixoforming: hot plastic deformation (SIMA), and modification with boron. DSC analysis allowed to establish the amount of liquid phase fraction vs temperature. Samples were heated up to the semi-solid temperature range - 1230°C, which corresponds to 17% (SIMA) and 30% (modified) of the liquid fraction. Then they were rapidly cooled. The obtained microstructures of samples were investigated for their suitability for SSP. The microstructure of X210CrW12 steel prepared by SIMA shows a globular microstructure with average grain size 57 μm. The samples after modification with 0.08% (weight pct) boron also feature a globular microstructure with the size of 46 μm. The grains possess an austenitic structure and are surrounded by an eutectic mixture

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Liquid demixing and microstructure formation in ternary Al–Sn–Cu alloys

Materials Science and Engineering A ◽

10.1016/j.msea.2007.10.043 ◽

2008 ◽

Vol 487 (1-2) ◽

pp. 456-467 ◽

Cited By ~ 29

Author(s):

D. Mirković ◽

J. Gröbner ◽

R. Schmid-Fetzer

Keyword(s):

Microstructure Formation ◽

Cu Alloys

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Semisolid Processing of Al-Sn-Cu Alloys for Bearing Applications

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.192-193.562 ◽

2012 ◽

Vol 192-193 ◽

pp. 562-568 ◽

Cited By ~ 6

Author(s):

Annalisa Pola ◽

Lorenzo Montesano ◽

Marcello Gelfi ◽

Roberto Roberti

Keyword(s):

Wear Resistance ◽

Semisolid Processing ◽

Globular Microstructure ◽

Cu Alloys ◽

Pin On Disk ◽

Wear Tests ◽

Microstructural Homogeneity ◽

Conventionally Cast

The aim of this work was to evaluate the advantages in using semisolid processing of Al-Sn alloys in order to improve microstructural homogeneity and, consequently, wear resistance. Different tests were performed on an Al3Sn4Cu by using ultrasound treatments during solidification to obtain an almost globular microstructure. Metallurgical characterizations and pin on disk wear tests were carried out on semisolid as well as on conventionally cast samples in order to assess the benefit of the treatment.

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Positive effect of Sc and Zr on globular microstructure formation in AA7075 thixoforming feedstock

10.1063/1.3589653 ◽

2011 ◽

Author(s):

Ł. Rogal ◽

J. Dutkiewicz ◽

L. Lityńska-Dobrzańska ◽

B. Olszowska-Sobieraj ◽

M. Modigell

Keyword(s):

Microstructure Formation ◽

Globular Microstructure ◽

Positive Effect

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Plastic deformation of θ ' in Al-4%Cu alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110027 ◽

1978 ◽

Vol 36 (1) ◽

pp. 576-577

Author(s):

Shrikant P. Bhat

Keyword(s):

Deformation Behavior ◽

Room Temperature ◽

Electron Microscopic Observation ◽

Bulk Alloy ◽

Electron Microscopic ◽

Cu Alloy ◽

Cu Alloys ◽

Orowan Mechanism ◽

The Subject ◽

Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

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TEM studies of amorphization processes and amorphous structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104303 ◽

1988 ◽

Vol 46 ◽

pp. 448-449

Author(s):

T. E. Mitchell ◽

R. B. Schwarz

Keyword(s):

Amorphous Materials ◽

Fission Products ◽

Rapid Quenching ◽

Surface Films ◽

List Type ◽

Oxide Glasses ◽

Crystalline Materials ◽

Amorphous Structures ◽

Amorphous Surface ◽

Interfacial Films

Traditional oxide glasses occur naturally as obsidian and can be made easily by suitable cooling histories. In the past 30 years, a variety of techniques have been discovered which amorphize normally crystalline materials such as metals. These include [1-3]:Rapid quenching from the vapor phase.Rapid quenching from the liquid phase.Electrodeposition of certain alloys, e.g. Fe-P.Oxidation of crystals to produce amorphous surface oxide layers.Interdiffusion of two pure crystalline metals.Hydrogen-induced vitrification of an intermetal1ic.Mechanical alloying and ball-milling of intermetal lie compounds.Irradiation processes of all kinds using ions, electrons, neutrons, and fission products.We offer here some general comments on the use of TEM to study these materials and give some particular examples of such studies.Thin specimens can be prepared from bulk homogeneous materials in the usual way. Most often, however, amorphous materials are in the form of surface films or interfacial films with different chemistry from the substrates.

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