Neutron diffraction and calorimetric study on Al-based metallic glasses

Clavaguera-Mora, M.T.; Rodríguez‐Viejo, J.; Jacovkis, D.; Touron, J. L.; Clavaguera, N.; Howells, W.S.

doi:10.1016/s0022-3093(01)00551-8

Cited by 10 publications

(5 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1b). This behavior is opposite to that observed in the amorphous alloys such as Zr 60 Al 15 Ni 25 [9] and Al 87 Ni 7 Nd 3 Cu 3 [11], whereby a decrease in heating rate results in a larger temperature interval between two overlapping exothermic peaks. Fig.…”

Section: Methodscontrasting

confidence: 66%

“…It is often observed that two or more crystallization events can occur almost simultaneously in some amorphous alloys during isochronal annealing at certain heating rates [9,10], as revealed by overlapping exothermic peaks in a differential scanning calorimetry (DSC) thermal analysis curve. An effective method to separate the crystallization events is to decrease the heating rate [9,11]. For example, it was reported that only a single exothermic peak on the DSC curve was observed when an amorphous Zr 60 Al 15 Ni 25 alloy was annealed at a heating rate of at least 20 K/min, but two distinct peaks were observed as the heating rate was decreased to 1 K/min.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Abnormal crystallization behavior of an (Al86Ni9La5)98Si2 amorphous alloy

Xiong

et al. 2015

Materials Letters

View full text Add to dashboard Cite

Section: Methodscontrasting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Abnormal crystallization behavior of an (Al86Ni9La5)98Si2 amorphous alloy

Xiong

et al. 2015

Materials Letters

View full text Add to dashboard Cite

“…The amorphous and nanostructured alloys show different (usually enhanced) physical, chemical, and mechanical properties from those of either the conventional polycrystalline or amorphous state, including a high strength (1500 MPa) and excellent high strength/weight ratio. Differential scanning calorimetry has proved to be the most effective method for characterising the kinetics of devitrivication including the nanocrystallisation in these amorphous alloys and is applied in a large number of studies, [75][76][77][78][79][80] although isothermal calorimetry has also been applied. 81 An instructive application of DSC to the study of devitrivication is the work by Gich et al 82 on the devitrivication of a range of rapidly solidified amorphous Al-Ni-Sm ternary alloys.…”

Section: Defect Annihilation Recovery and Recrystallisation In Wrougmentioning

confidence: 99%

“…Differential scanning calorimetry has proved to be the most effective method for characterising the kinetics of devitrivication including the nanocrystallisation in these amorphous alloys and is applied in a large number of studies, [75][76][77][78][79][80] although isothermal calorimetry has also been applied. 81 An instructive application of DSC to the study of devitrivication is the work by Gich et al 82 on the devitrivication of a range of rapidly solidified amorphous Al-Ni-Sm ternary alloys.…”

Section: Devitrivication; Nanocrystallisationmentioning

confidence: 99%

Analysis of aluminium based alloys by calorimetry: quantitative analysis of reactions and reaction kinetics

Starink¹

2004

International Materials Reviews

286

108

View full text Add to dashboard Cite

Differential scanning calorimetry (DSC) and isothermal calorimetry have been applied extensively to the analysis of light metals, especially Al based alloys. Isothermal calorimetry and differential scanning calorimetry are used for analysis of solid state reactions, such as precipitation, homogenisation, devitrivication and recrystallisation; and solid-liquid reactions, such as incipient melting and solidification, are studied by differential scanning calorimetry. In producing repeatable calorimetry data on Al alloys, sample preparation, reproducibility and baseline drift need to be considered in detail. Calorimetry can be used effectively to study the different solid state reactions and solid-liquid reactions that occur during the main processing steps of Al based alloys (solidification, homogenisation, precipitation). Also, devitrivication of amorphous and ultrafine grained Al based powders and flakes can be studied effectively. Quantitative analysis of the kinetics of reactions is assessed through reviewing the interrelation between activation energy analysis methods, equivalent time approaches, impingement parameter approaches, mean field models for precipitation, the Johnson-Mehl-Avrami-Kolmogorov model, as well as novel models which have not yet found application in calorimetry. Differential scanning calorimetry has occasionally been used in attempts to measure the volume fractions of phases present in Al based alloys, and attempts at determining volume fractions of intermetallic phases in commercial alloys and amounts of devitrified phase in glasses are reviewed. The requirements for the validity of these quantitative applications are also reviewed.Keywords: Differential scanning calorimetry, Precipitation, Aluminium, Modelling, Transformation IMR/419 IntroductionCalorimetry is an analysis technique that is part of a group of techniques collectively known as thermal analysis methods. In its broadest sense, thermal analysis refers to the measurement of changes in properties of substances under a controlled temperature program. Thermal analysis techniques can be classified according to the type of temperature program that the sample is subjected to and the measured (output) signal. The most commonly used temperature programs are either isothermal hold or heating (scanning) at constant rate, while more recently, temperature modulated scanning and reaction controlled heating have also found application. The signals measured in thermal analysis can include heat flows, temperature changes, mass, evolved gasses, length changes, elastic modulus, and many other properties that characterise properties or reactions of interest. Calorimetry refers to thermal analysis methods that measure the heat evolution from a sample under a controlled temperature program. The two most often applied calorimetry techniques are isothermal calorimetry and differential scanning calorimetry (DSC), which, as the name suggests, is by definition non-isothermal (i.e. a temperature scan). Apart from the more common applications to polymers,...

show abstract

“…Debido al alto contenido de elementos de aleación en estas aleaciones ocurren procesos de recristalización, que originan la formación y disolución de nanopartículas que participan de manera activa en el reforzamiento de la aleación [12,13,14]. Para aleaciones obtenidas por solidificación rápida puede ocurrir recristalización a temperaturas relativamente bajas [15,16]. Este proceso interfiere con la precipitación, por lo que ocurre una competencia entre ambos.…”

Section: Figuraunclassified

Efecto de las variables experimentales sobre la microdureza en aleaciones Al-6Si-3Cu-xMg T6

et al. 2008

View full text Add to dashboard Cite

RESUMENTres aleaciones cuaternarias Al-6Si-3Cu-xMg (x = 0.59, 3.80 y 6.78 % en peso) fueron producidas utilizando fundición convencional de lingotes y solidificación rápida mediante "melt-spinning". El estudio se concentró en investigar el efecto del contenido de Mg y del tiempo y la temperatura de envejecido sobre los precipitados y la microdureza. Las aleaciones se sometieron a tratamientos térmicos T6, consistentes en calentar las muestras a 480 ºC por 12 h y envejecido a 150, 180 y 210 ºC, durante tiempos comprendidos entre 0.05 y 100 horas. Se aplicaron diseños multifactoriales, resumidos en la dependencia VHN= f (t, T, %Mg), donde VHN es la microdureza Vickers, t es el tiempo y T la temperatura de envejecido. Se utilizaron técnicas de microscopía electrónica de transmisión y microdureza. Los precipitados obtenidos fueron diferentes: CuAl 2 en forma de aguja para las aleaciones con 0.59 % de Mg; y Q (Al 5 Cu 2 Mg 8 Si 6 ) irregulares para las aleaciones con 3.80 y 6.78 % de Mg. Para las aleaciones obtenidas por solidificación rápida, el factor que más influyó sobre la microdureza fue la temperatura, seguido por el contenido de Mg y el tiempo de envejecido. El aumento del contenido de Mg origina mayores microdurezas. Para las aleaciones obtenidas por solidificación convencional la temperatura es el único factor que provoca cambios significativos sobre la microdureza.Palabras clave: Melt-spinning, aleaciones de aluminio, magnesio, envejecido, precipitación, recristalización. Effect of the experimental variables on the Al-6Si-3Cu-xMg T6 microhardness alloy ABSTRACTThree Al-6Si-3Cu-xMg (x = 0.59, 3.80 and 6.78 wt. %) alloys were produced using conventional ingot casting metallurgy and melt-spinning. The study was focused to investigate the effect of Magnesium content and aging time ant temperature on precipitates and microhardness. Obtained alloys were solution heat treated at 480 ºC for 12 h and aged at 150, 180 and 210 °C for times between 0.05 and 100 h. Multifactorial designs were used, summarized in the dependency: VHN= f (t, T, %Mg), where VHN is Vickers microhardness, t is aging time and T is aging temperature. Transmission Electron Microscopy and microhardness techniques were used. Results shown variations in precipitates composition: CuAl 2 needles for the alloys with 0.59% Mg and Q (Al 5 Cu 2 Mg 8 Si 6 ) with irregular shapes, for the alloys with 3.80 and 6.78% Mg. For melt-spinning alloys, temperature originates the most significant variation on microhardness, followed by Mg content and aging time. The increase of Mg content originates greater microhardnesses. For conventionally cast alloys temperature is the only factor that significantly changes microhardness.

show abstract

Neutron diffraction and calorimetric study on Al-based metallic glasses

Cited by 10 publications

References 12 publications

Abnormal crystallization behavior of an (Al86Ni9La5)98Si2 amorphous alloy

Abnormal crystallization behavior of an (Al86Ni9La5)98Si2 amorphous alloy

Analysis of aluminium based alloys by calorimetry: quantitative analysis of reactions and reaction kinetics

Efecto de las variables experimentales sobre la microdureza en aleaciones Al-6Si-3Cu-xMg T6

Contact Info

Product

Resources

About