scholarly journals Metallurgical Preparation of Nb–Al and W–Al Intermetallic Compounds and Characterization of Their Microstructure and Phase Transformations by DTA Technique

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 2001
Author(s):  
Tomas Cegan ◽  
Daniel Petlak ◽  
Katerina Skotnicova ◽  
Jan Jurica ◽  
Bedrich Smetana ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Intermetallic Compounds ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Al Alloys ◽  
Vacuum Induction Melting ◽  
Al Alloy ◽  
Induction Melting ◽  
Arc Melting

The possibilities of metallurgical preparation of 40Nb-60Al and 15W-85Al intermetallic compounds (in at.%) by plasma arc melting (PAM) and vacuum induction melting (VIM) were studied. Both methods allow easy preparation of Nb–Al alloys; however, significant evaporation of Al was observed during the melting, which affected the resulting chemical composition. The preparation of W–Al alloys was more problematic because there was no complete re-melting of W during PAM and VIM. However, the combination of PAM and VIM allowed the preparation of W–Al alloy without any non-melted parts. The microstructure of Nb–Al alloys consisted of Nb2Al and NbAl3 intermetallic phases, and W–Al alloys consisted mainly of needle-like WAl4 intermetallic phase and Al matrix. The effects of melting conditions on chemical composition, homogeneity, and microstructure were determined. Differential thermal analysis was used to determine melting and phase transformation temperatures of the prepared alloys.

The Intermetallic Phases in Sand Casting Magnesium Alloys for Elevated Temperature

2011 ◽  
Vol 690 ◽  
pp. 214-217 ◽  
Author(s):  
Andrzej Kiełbus ◽  
Tomasz Rzychoń
Keyword(s):  
Solid Solution ◽  
Elevated Temperature ◽  
Grain Boundaries ◽  
Magnesium Alloys ◽  
Solution Structure ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Phase Identification ◽  
Al Alloy ◽  
Cast Microstructure

In the present article, the phase identification of four magnesium alloys: Mg-9wt%Al, Mg-8wt%Al-2wt%Ca-0.5wt%Sr, Mg-5wt%Y-4wt%RE and Mg-3wt%Nd-1wt%Gd were studied. The results showed that Mg-9wt%Al alloy contains only the Mg17Al12 intermetallic phase in α-Mg matrix. As-cast microstructure of Mg-8wt%Al-2wt%Ca-0.5wt%Sr alloy consist of α-Mg matrix with (Al,Mg)2Ca and (Al,Mg)4Sr phases. The Mg-5wt%Y-4wt%RE alloy showed several phases. This alloy was characterized by a solid solution structure α-Mg with eutectic α-Mg + Mg14Y2Nd on grain boundaries. The precipitates of MgY, Mg2Y, Mg24Y5 phases have been also observed. The Mg-3wt%Nd-1wt%Gd alloy composed mainly of a solid solution structure α-Mg with eutectic α-Mg + Mg3(Nd,Gd) on the grain boundaries. The regular precipitates of MgGd3 phase have been also observed.

Boron Effect on Hardenability of High Thickness Forged Steel Materials

2016 ◽  
Vol 879 ◽  
pp. 1282-1287 ◽  
Author(s):  
Sabrina Mengaroni ◽  
Paolo Emilio di Nunzio ◽  
Stefano Neri ◽  
Massimo Calderini ◽  
Claudio Braccesi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Laboratory Scale ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Boron Addition ◽  
Hot Rolled ◽  
Industrial Demand

To fulfill the industrial demand of forged steels with high mechanical and microstructural requirements coupled with reduced cost, the possibility to decrease the content of Mo and other elements has been evaluated. In order to do that, the effect of boron addition (up to 30 ppm) on the steel hardenability has been investigated on two steels with different chemical composition at laboratory scale. In particular, the steel chemical composition has been designed in order to make effective the B addition in terms of hardenability. Two 80 kg ingots cast by a vacuum induction melting plant have been hot rolled by a pilot mill. The effect of B addition on hardenability has been evaluated and compared to that of steel for same application but without B. Results show an improvement of hardenability if 30 ppm B are added even if a Mo reduction is performed.

Production of Fe3Al-Based Intermetallic Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
Vinod K. Sikka
Keyword(s):  
Surface Finish ◽  
National Laboratory ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Intermetallic Alloys ◽  
Vacuum Arc Remelting ◽  
Oak Ridge ◽  
Arc Melting

ABSTRACTThe melting of Fe3Al-based alloys at the Oak Ridge National Laboratory (ORNL) and commercial vendors is described. The melting processes evaluated include arc melting, air-induction melting (AIM), vacuum-induction melting (VIM), vacuum-arc remelting (VAR), and electroslag remelting (ESR). The quality of the ingots studied are based on internal soundness and the surface finish obtained. The ingots were analyzed for impurity levels observed in the alloys by various melting processes. Recommendations are made for viable processes for commercial melting of these alloys.

Effect of Cooling Rate on the Microstructure of Cu80Cr20 Alloys

2011 ◽  
Vol 694 ◽  
pp. 704-707
Author(s):  
Z.M. Zhou ◽  
W.J. Huang ◽  
J. Luo ◽  
X.P. Li ◽  
T. Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cooling Rate ◽  
Electromagnetic Levitation ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Rich Phase ◽  
Arc Melting ◽  
Splat Quenching ◽  
Scanning Electron

The effect of cooling rate on the microstructure of Cu80Cr20 alloys was studied by using vacuum non-consumable arc melting, vacuum induction melting, electromagnetic levitation and splat quenching. The microstructure evolution of the Cr-rich were analyzed by scanning electron microscopy (SEM) and optical microscopy. The results showed that nonuniform Cr-rich dendrite distributes on Cu-rich matrix for arc melted alloys and uniform Cr-rich dendrite distributes on Cu-rich matrix for electromagnetic levitation melted alloys and vacuum induction melted alloys. However, the Cr-rich phase show both dendrites and spheroids for splat quenched alloys. This means liquid phase separation occurred during rapid solidification.

Influence of the Nickel on the Corrosion Behavior of Al-Mg-Sc-Zr Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1123-1128
Author(s):  
W.T. Zhao ◽  
De Sheng Yan ◽  
Li Jian Rong
Keyword(s):  
Corrosion Behavior ◽  
Intergranular Corrosion ◽  
Intermetallic Phase ◽  
Morphological Characteristics ◽  
Localized Corrosion ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Exfoliation Corrosion ◽  
Β Phase ◽  
Zr Alloy

The corrosion behavior of cold worked Al-Mg-Sc-Zr-Ni alloys prepared by vacuum induction melting in acidic chloride solution was studied. The morphological characteristics of the corroded specimens were examined by OM(optical microscopy), SEMand EDX techniques. The results indicated that the intergranular and exfoliation corrosion susceptibility dramatically depended on the Ni content. The Al-Mg-Sc-Zr alloy with 0 and 0.5 wt.% Ni were lightly susceptible to intergranular corrosion as the precipitation of Mg2Al3 phases presented at grain boundaries and the Al3Ni particles were finely dispersive. The intergranular corrosion was enhanced by the Al3Ni particles enrichment and became pitting corrosion with increasing Ni to 1.0 wt.%. Finally, the exfoliation corrosion happened to the alloy with 2.0wt.% Ni. This trend correlated well with the electrochemical property and distribution of Al3Ni phases. The corrosion potential of Al3Ni intermetallic phase is nobler than the β phase and the matrix, which result in an appearance of galvanic coupling. In addition, the increase of Al3Ni particles enlarged the attack area and the inhomogeneous segments of Al3Ni and Al3Mg2 phases accelerated the localized corrosion.

The Thermal Diffusivity of Mg-Al-Sr and Mg-Al-Ca-Sr Sand Casting Magnesium Alloys

2012 ◽  
Vol 326-328 ◽  
pp. 249-254
Author(s):  
Andrzej Kiełbus ◽  
Tomasz Rzychoń ◽  
Grzegorz Moskal
Keyword(s):  
Thermal Diffusivity ◽  
Chemical Composition ◽  
Magnesium Alloys ◽  
Volume Fraction ◽  
Intermetallic Phases ◽  
Sand Casting ◽  
Al Alloy ◽  
Temperature Dependent ◽  
Total Volume Fraction ◽  
Increasing Temperature

In the present study, the thermal diffusivity of four sand casting magnesium alloys: Mg-9Al-1Zn, Mg-6Al-2Sr, Mg-9Al-1.5Ca-0.3Sr and Mg-9Al-2.2Ca-0.8Sr were studied. Sand casting was performed at 730-780°C temperatures. Thermal diffusivity was measured by a LFA 427 Netzsch apparatus. The thermal diffusivity of the investigated alloys was chemical composition and temperature dependent and increased with increasing temperature. The thermal diffusivity of Mg-Al-Ca-Sr alloys was higher than that of Mg-Al alloy, because the total volume fraction of intermetallic phases in alloys containing calcium and strontium is larger than that in Mg-Al alloy. The formation of intermetallic phases caused the consumption of the solute element in the α-Mg matrix, and improved the thermal diffusivity of the Mg-Al-Ca-Sr magnesium alloy.

Study on the Microstructure and Properties of Low Cost TiFeAl Alloy

2013 ◽  
Vol 477-478 ◽  
pp. 1288-1292
Author(s):  
Bo Long Li ◽  
Tong Liu ◽  
Jie Yuan ◽  
Zuo Ren Nie
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Low Cost ◽  
High Strength ◽  
Al Alloys ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Β Phase ◽  
Transmission Electron ◽  
Solution Strengthening

The high strength and low cost Ti-Fe based alloy was produced by double vacuum induction melting method followed by hot deformation. The microstructure has been investigated by Optical Microscopy, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The microstructure of as-forged alloy is composed of α and β phase without the precipitation of TiFe intermetallic compound. The Ti-Fe-Al alloys show good comprehensive mechanical properties, demonstrating ultimate tensile strength of 1100MPa and elongation above10%. The results indicate the Fe is a good candidate for solution strengthening and simultaneously increasing ductility in titanium alloys. Effect of the Fe and Al elements on the microstructure and mechanical properties have been discussed.

Microstructural and Mechanical Characterization of Nitinol GTAW and FB Welds of Titanium

2006 ◽  
Vol 509 ◽  
pp. 165-170 ◽  
Author(s):  
Alla Kabatskaia Ivanovna ◽  
Victor M. López-Hirata ◽  
Eduardo Oliva López ◽  
Ricardo Rodríguez Figueroa ◽  
Jorge Rodríguez Miramontes
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Characterization ◽  
Dendritic Structure ◽  
Intermetallic Phases ◽  
Atomic Diffusion ◽  
Rich Phase ◽  
Gas Tungsten Arc ◽  
Gtaw Process

Microstructural and mechanical characterization of Nitinol gas tungsten arc weld (GTAW) and furnace brazing (FB) welds for grade 1 titanium plates are carried out in order to study the microstructure developed after welding and its effect on the mechanical properties of welds. The GTAW process yields the highest hardness weld. The constituents for this weld consist of a dendritic structure of NiTi and NiTi2 intermetallic phases. The FB process promotes a change of the welds chemical composition due to atomic diffusion of Ti. The weld microconstituents consist of a mixture of a Ti-rich and NiTi2 eutectic and a proeutectic Ti-rich phase.

Characterization of a Fe-Based Alloy System for an AFCI Metallic Waste Form

2009 ◽  
Author(s):  
Mark J. Williamson ◽  
Robert L. Sindelar
Keyword(s):  
Waste Management ◽  
Management Strategy ◽  
Alloy System ◽  
Management Program ◽  
Waste Form ◽  
Vacuum Induction Melting ◽  
Phase Assemblage ◽  
Induction Melting ◽  
High Level

The AFCI waste management program aims to provide a minimum volume stable waste form for high level radioactive waste from the various process streams. The AFCI Integrated Waste Management Strategy document has identified a Fe-Zr metallic waste form (MWF) as the baseline alloy for disposal of Tc metal, undissolved solids, and TRUEX fission product wastes. Several candidate alloys have been fabricated using vacuum induction melting to investigate the limits of waste loading as a function of Fe and Zr content. Additional melts have been produced to investigate source material composition. These alloys have been characterized using SEM/EDS and XRD. Phase assemblage and specie partitioning of Re metal (surrogate for Tc) and noble metal FP elements into the phases is reported.

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