Intermetallic compound layer growth at the interface of solid refractory metals molybdenum and niobium with molten aluminum

Tunca, N.; Smith, Richard W.

doi:10.1007/bf02651649

Cited by 17 publications

(8 citation statements)

References 18 publications

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“…The layer thickness vs. annealing time relation was found: d = 0.0093 · t 1.34 (d -thickness of the layer in mm, t -time in min.). It was also found that the rate of the layer growth substantially exceeds a parabolic growth reported in literature [20][21][22][23] for intermetallic phases received due to interdiffusion of the components in the solid state. Microstructure of the layer that was formed at the front of the Mg-Al reaction was shown in Fig.…”

Section: Resultsmentioning

confidence: 76%

Formation of Layered Mg/Eutectic Composite Using Diffusional Processes at the Mg-Al Interface

Dziadoń¹,

Mola²,

Błaż³

2011

Archives of Metallurgy and Materials

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A processing technique has been developed to produce a layered magnesium-intermetallic compound light composite from elemental magnesium and aluminium sheets. Structural examination and measurements of transition layer grown at the magnesium-aluminium interface at high annealing temperature were performed. It was found using Mg/Al diffusion couple that solid state diffusion results in development of Al 3 Mg 2 and Mg 17 Al 12 intermetallic compounds, which are separated into two sublayers. The rate of the layer growth substantially increases with the appearance of the liquid phase at the Mg-Al interface. The microstructure resulted from the partial solidification contains an eutectic composed of Mg 17 Al 12 intermetallic compound and solid solution aluminium in magnesium. The structural processes, which transform the magnesium-aluminium interface, can be applied for fabrication of layered magnesium-eutectic composites. Alternately stacked magnesium and aluminium sheets, formed into a packet, were heated until aluminium was exhausted throughout the course of the Mg-Al reaction with the liquid phase contribution. As a result, the composite containing residual magnesium and layers of eutectic mixture (Mg 17 Al 12 and solid solution of aluminium in magnesium) was obtained. Rapid solidification resulted in fine-grained eutectic microstructure development. Using the presented method, composites with required thickness ratio of magnesium and the eutectic layers can be obtained by choosing appropriate thickness ratio of starting magnesium and aluminium sheets.Keywords: metal-matrix composites, layered composite, intermetallicsOpracowano metodę otrzymywania kompozytu zbudowanego z warstw magnezu i warstw zawierających związek między-metaliczny, wykorzystując jako substraty blachę magnezu i blachę aluminium. Stosując złącze dyfuzyjne Mg/Al przeprowadzono badania zmian strukturalnych zachodzących pod wpływem temperatury na granicy międzyfazowej magnez-aluminium oraz badania wzrostu warstwy produktów reakcji. Stwierdzono, że warstwa ta, utworzona w wyniku zachodzących w stanie stałym przemian dyfuzyjnych, składa się z dwu podwarstw o strukturze związków międzymetalicznych: Al 3 Mg 2 i Mg 17 Al 12 . Szybkość wzrostu warstwy zwiększa się znacznie, gdy na granicy Mg-Al pojawia się faza ciekła. Mikrostruktura utworzona podczas krzepnięcia zawiera głównie eutektykę, składającą się ze związku międzymetalicznego Mg 17 Al 12 i roztworu stałego aluminium w magnezie. Zjawiska zachodzące na granicy magnez-aluminium zostały wykorzystane do formowania kompozytu warstwowego magnez-eutektyka. Arkusze blachy magnezu i blachy aluminium ułożone naprzemiennie w pakiet wygrzewa się do momentu wyczerpania się aluminium w reakcji z magnezem zachodzącej z udziałem fazy ciekłej. W wyniku powstaje kompozyt składający się z warstw pozostałego magnezu i warstw eutektyki zbudowanej z Mg 17 Al 12 i roztworu stałego aluminium w magnezie. Gwałtowne krzepnięcie pozwala uzyskać eutektykę o drobnoziarnistej mikrostrukturze. Przez dobór stosunku grubości wyjś...

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Section: Resultsmentioning

confidence: 76%

Formation of Layered Mg/Eutectic Composite Using Diffusional Processes at the Mg-Al Interface

Dziadoń¹,

Mola²,

Błaż³

2011

Archives of Metallurgy and Materials

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“…Although the difference in melting points is very large, Mo and Al form a variety of intermetallic compounds depending on the concentration of the two metals. The few experimental investigations under equilibrium conditions where Mo was exposed to liquid Al [5] confirmed the formation of up to five different intermetallic layers depending on the operating temperature. An interesting feature of that study [5] was the observation of the intermetallic phase Al Mo in the Al-Mo interface, it possessed the highest hardness among the various intermetallics (882 HV), was brittle, and was poorly adhering to the base metal Mo.…”

Section: B Aging Characteristics Of the Conducting Alloy During Intementioning

confidence: 90%

“…The few experimental investigations under equilibrium conditions where Mo was exposed to liquid Al [5] confirmed the formation of up to five different intermetallic layers depending on the operating temperature. An interesting feature of that study [5] was the observation of the intermetallic phase Al Mo in the Al-Mo interface, it possessed the highest hardness among the various intermetallics (882 HV), was brittle, and was poorly adhering to the base metal Mo. Similar intermetallic formation was reported during the diffusion bonding of these two metals [6].…”

Section: B Aging Characteristics Of the Conducting Alloy During Intementioning

confidence: 90%

On the Operation of a Press Pack IGBT Module Under Short Circuit Conditions

Gunturi

Schneider

2006

IEEE Trans. Adv. Packag.

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Press pack insulated gate bipolar transistor (IGBT) modules connected in series for high-voltage direct current (HVDC) converter applications are designed such that when a failure occurs, it occurs in a safe manner by the formation of a stable short circuit, while redundant modules take up the voltage blocking function of the failed module. One such design using individual pressure contacts is described and the events occurring from the initiation of the short circuit to its final failure due to open circuit are reported from an electronics packaging materials design point of view. Experiments to hasten the failure under accelerated test conditions on modules were performed and interrupted at various stages of operation under a short circuit condition. The formation and subsequent aging of the metallurgical alloy under short circuit conditions was investigated by analyzing cross sections of the alloy forming the short circuit. Liquid metal corrosion along with the formation of intermetallics with poor conductivities lead to the final failure by open circuit.Index Terms-high-voltage direct current (HVDC), insulated gate bipolar transistor (IGBT), intermetallics, liquid metal corrosion, power electronics packaging, press pack modules, short circuit failure mode.

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“…From the literature, [19,[27][28][29][30][31] it has been generally accepted that the defining rate characteristics of the dissolution of a solid metal in a liquid-metal environment are governed by the following law:…”

Section: Formulation For Iron Dissolution During the Formation Of mentioning

confidence: 99%

Theoretical Investigation of the Interfacial Reactions during Hot-Dip Galvanizing of Steel

Mandal

Balasubramaniam

Mehrotra

2009

Metall Mater Trans A

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In the modern galvanizing line, as soon as the steel strip enters the aluminum-containing zinc bath, two reactions occur at the strip and the liquid-zinc alloy interface: (1) iron rapidly dissolves from the strip surface, raising the iron concentration in the liquid phase at the strip-liquid interface; and (2) aluminum forms a stable aluminum-iron intermetallic compound layer at the strip-coating interface due to its greater affinity toward iron. The main objective of this study is to develop a simple and realistic mathematical model for better understanding of the kinetics of galvanizing reactions at the strip and the liquid-zinc alloy interface. In the present study, a model is proposed to simulate the effect of various process parameters on iron dissolution in the bath, as well as, aluminum-rich inhibition layer formation at the substrate-coating interface. The transient-temperature profile of the immersed strip is predicted based on conductive and convective heat-transfer mechanisms. The inhibition-layer thickness at the substrate-coating interface is predicted by assuming the cooling path of the immersed strip consists of a series of isothermal holds of infinitesimal time-step. The influence of galvanizing reaction is assessed by considering nucleation and growth mechanisms at each hold time, which is used to estimate the total effect of the immersion time on the formation mechanism of the inhibition layer. The irondissolution model is developed based on well established principles of diffusion taking into consideration the area fraction covered by the intermetallic on the strip surface during formation of the inhibition layer. The model can be effectively used to monitor the dross formation in the bath by optimizing the process parameters. Theoretical predictions are compared with the findings of other researchers. Simulated results are in good agreement with the theoretical and experimental observation carried out by other investigators.

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Intermetallic compound layer growth at the interface of solid refractory metals molybdenum and niobium with molten aluminum

Cited by 17 publications

References 18 publications

Formation of Layered Mg/Eutectic Composite Using Diffusional Processes at the Mg-Al Interface

Formation of Layered Mg/Eutectic Composite Using Diffusional Processes at the Mg-Al Interface

On the Operation of a Press Pack IGBT Module Under Short Circuit Conditions

Theoretical Investigation of the Interfacial Reactions during Hot-Dip Galvanizing of Steel

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