Microstructure and Oxidation Resistance of Mechanically Alloyed and Sintered Ni-Nb and Ni-Nb-Ta Alloys

2017 ◽  
Vol 899 ◽  
pp. 19-24
Author(s):  
Lucas Moreira Ferreira ◽  
Stephania Capellari Rezende ◽  
Antonio Augusto Araújo Pinto da Silva ◽  
Gael Yves Poirier ◽  
Gilberto Carvalho Coelho ◽  
...  
Keyword(s):  
Ball Milling ◽  
Oxidation Resistance ◽  
Energy Dispersive Spectrometry ◽  
High Energy ◽  
Milling Process ◽  
Ternary Alloys ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Static Oxidation ◽  
Energy Ball

The present work reports on the microstructure and oxidation resistance of Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys produced by high-energy ball milling and subsequent sintering. The sintered samples were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive spectrometry, and static oxidation tests. Homogeneous microstructures of the binary and ternary alloys indicated the major presence of the β-Ni3Nb compound as matrix, which dissolved large amounts of tantalum. Consequently, the β-Ni3Nb peaks moved toward the direction of smaller diffraction angles. Iron contamination lower than 6.7 at.-% was detected by EDS analysis, which were picked-up during the previous ball milling process. After the static oxidation tests (1100°C for 4 h) the sintered Ni-25Nb, Ni-20Nb-5Ta and Ni-15Nb-10Ta alloys presented mass gains of 31.5%, 30.5% and 28.8%, respectively. Despite the higher densification of the Ni-15Nb-10Ta alloy, the results suggested that the tantalum addition contributed to improve the oxidation resistance of the β-Ni3Nb compound.

On the Phase Transformation in Mechanically Alloyed Ni-Nb and Ni-Ta and Ni-Nb-Ta Powders

2012 ◽  
Vol 727-728 ◽  
pp. 222-226 ◽  
Author(s):  
Ana Clara Ferraretto ◽  
Erika Coaglia Trindade Ramos ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Phase Transformation ◽  
Ball Milling ◽  
High Energy ◽  
Milling Process ◽  
Spontaneous Ignition ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Energy Ball ◽  
Rotary Speed ◽  
Steel Balls

This paper reports on the phase transformation during the preparation of Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta and Ni-15Nb-10Ta (at-%) powders by high-energy ball milling from elemental powders. The milling process was performed in a planetary ball milling using stainless steel balls and vials, rotary speed of 300rpm, and a ball-to-powder of 10:1. To minimize contamination and spontaneous ignition the powders were handled under argon atmosphere in a glove box. The milled powders were characterized by means of X-ray diffraction techniques. Results indicated that the Ni atoms were preferentially dissolved into the Nb (and/or Ta) lattice at the initial milling times, which contributed to change the relative intensity on the diffraction peaks. After the dissolution of Nb (and/or Ta) into the Ni lattice, the Ni peaks were moved to the direction of lower diffraction angles in Ni-25Nb, Ni-25Ta, Ni-20Nb-5Ta, Ni-15Nb-10Ta powders, indicating that the mechanical alloying was achieved. .

Phase Transformations in Mechanically Alloyed and Sintered Ti-XMg-22Si-11B (X = 2 and 7 at.-%at) Powders

2017 ◽  
Vol 899 ◽  
pp. 3-8
Author(s):  
Luiz Otávio Vicentin Maruya ◽  
Bruno Bacci Fernandes ◽  
Mario Ueda ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Energy Dispersive Spectrometry ◽  
Weight Ratio ◽  
High Energy ◽  
X Ray Diffraction ◽  
Amorphous Halo ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Equilibrium Structures ◽  
Energy Ball

This work reports on effect of magnesium addition on the Ti6Si2B stability in Ti-xMg-22Si-11B (x = 2 and 6 at.-%) alloys prepared by high-energy ball milling and subsequent sintering. Ball milling was conducted under Ar atmosphere in stainless steel vials and balls, 300 rpm, and a ball-to-powder weight ratio of 10:1. Following, the powders milled for 10 h were axially compacted in order to obtain cylinder samples with 6 mm diameter. To obtain the equilibrium structures the green samples were sintered at 1100°C for 4 h under Ar atmosphere. X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry were used to characterize the as-milled powders and sintered samples. Extended Ti solid solution were found in the Ti-2Mg-22Si-11B and Ti-7-Mg-Si-B powders milled for 20 min and 60 min, respectively, whereas an amorphous halo was produced on Ti-2Mg-22Si-11B powders milled for 420 min. The increase of Mg amount in the starting powder mixture has inhibited the Ti6Si2B formation in the mechanically alloyed and sintered Ti-7Mg-22Si-11B alloy.

Structural Evaluation of Mechanically Alloyed Ti-Nb Powders

2008 ◽  
Vol 591-593 ◽  
pp. 141-146 ◽  
Author(s):  
Y.A. Giffoni ◽  
Erika Coaglia Trindade Ramos ◽  
Hugo Ricardo Zschommler Sandim ◽  
M.T.T. Pacheco ◽  
Gilbert Silva ◽  
...  
Keyword(s):  
Ball Milling ◽  
Energy Dispersive Spectrometry ◽  
Structural Heterogeneity ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Structural Evaluation ◽  
Crystallite Sizes ◽  
Homogeneous Structures ◽  
Final Amount

This work discusses on the structural evaluation of mechanically alloyed Ti-Nb powders. The Nb amount was varied between 20 and 50 wt-%. The milling process was carried out in a planetary Fritsch P-5 ball mill under Ar atmosphere. The structural evaluation was conducted by scanning electron microscopy, X-ray diffraction, and energy dispersive spectrometry. During ball milling it was noted an excessive agglomeration of ductile Ti-Nb powders on the balls and vial surfaces, and the final amount of remaining powders was then drastically reduced into the vials. This fact was more pronounced with the increased Nb amount in starting powders. Typical lamella structures were formed during ball milling, which were refined for the longest milling times, and fine and homogeneous structures were formed in Ti-Nb (Nb=20-50wt-%) powders. XRD results indicated that the full width at half maximum values of Ti peaks were continuously increased while that the crystallite sizes were reduced for longer milling times due to the severe plastic deformation provided during ball milling of Ti-Nb powders. However, the EDS analysis revealed the presence of Nb-rich regions in Ti-Nb powders after ball milling. The critical ball milling behavior of ductile Ti- Nb powders contributed for reducing the yield powder and increasing the structural heterogeneity.

scholarly journals Investigation of the Reaction between Fe2O3 and Si Activated by Ball Milling

1996 ◽  
Vol 51 (8) ◽  
pp. 915-922 ◽  
Author(s):  
Giorgio Concas ◽  
Francesco Congiu ◽  
Anna Corrias ◽  
Carlo Muntoni ◽  
Giorgio Paschina ◽  
...  
Keyword(s):  
Ball Milling ◽  
Oxygen Transfer ◽  
Amorphous Matrix ◽  
High Energy ◽  
Milling Process ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermediate Phases ◽  
Energy Ball

Abstract The path of the reaction between Fe2O3 and Si, activated by high energy ball milling, has been investigated by X-ray diffraction and Mössbauer spectroscopy. Hematite reduction involves oxygen transfer from Fe to Si with the formation of intermediate phases containing Fe(II), which are then reduced to Fe(0). A steady state is reached in the milling process where the reduction of stoichiometric amounts of Fe2O3 and Si is not complete and an amount of Fe(II) in an amorphous matrix still remains. The same intermediate compounds are also observed in the milling process of mixtures with higher Fe2O3 /Si molar ratio.

Ni3Fe Mechanically Alloyed: “Shock Mode” versus “Friction Mode”

2011 ◽  
Vol 672 ◽  
pp. 153-156 ◽  
Author(s):  
Virgiliu Călin Prică ◽  
Traian Florin Marinca ◽  
Florin Popa ◽  
Ionel Chicinaş
Keyword(s):  
Grain Size ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Grain Sizes ◽  
Friction Mode ◽  
Energy Ball ◽  
Scherrer Formula ◽  
Mode Versus

Ni3Fe powder has been obtained by high energy ball milling from elemental powders. We used two extreme conditions for milling: “friction mode” – friction between powder and ball/vial– and “shock mode” – direct impact of ball to powders. The influence of milling mode - friction and shock – was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was observed that the Ni3Fe grain size obtained by “friction mode” after 30 hours of milling was around 10 nm. For “shock mode” milling the average grain sizes was around 17 nm after 20 hours. The grain size was calculated using Williamson-Hall formula for both, “shock mode” and “friction mode” of milled powders and Scherrer formula for annealed powders. The powders were subjected to an annealing (30 min. at 350 °C) in order to eliminate the internal stress accumulated to the milling process and to finish the Ni3Fe phase formation.

scholarly journals Effect of Ball Size on the Microstructure and Morphology of Mg Powders Processed by High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1621
Author(s):  
Jesus Rios ◽  
Alex Restrepo ◽  
Alejandro Zuleta ◽  
Francisco Bolívar ◽  
Juan Castaño ◽  
...  
Keyword(s):  
Ball Milling ◽  
Morphological Evolution ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Ball Size ◽  
Powder Particles ◽  
Energy Ball

Commercial powders of pure magnesium were processed by high-energy ball milling. The microstructural and morphological evolution of the powders was studied using scanning electron microscopy (SEM), energy dispersive spectrometry (EDX) and X-ray diffraction (XRD). From the results obtained, it was determined that the ball size is the most influential milling parameter. This was because balls of 1 mm diameter were used after a previous stage of milling with larger balls (i.e., 10 and 3 mm). The powder particles presented an unusual morphology with respect to those observed in the Mg-milling literature and recrystallization phenomena. Moreover, the result strongly varied depending on the ball-to-powder weight ratio (BPR) used during the milling process.

scholarly journals Analysis of the influence of β-TCP particle size on deagglomeration processes

2020 ◽  
Vol 9 (4) ◽  
pp. e175943067
Author(s):  
João Augusto Martins Almeida ◽  
Bruna Horta Bastos Kuffner ◽  
Gilbert Silva ◽  
Patrícia Capellato ◽  
Daniela Sachs
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
Heterogeneous Distribution ◽  
X Ray ◽  
Energy Ball

There are a class of material widely used in bone tissue repair. This material is calcium phosphate ceramics (CPCs)that can be used on two phases: α and β. However, β-TCP is more used in bone regeneration than α–TCP due to the biocompatible and bioactive properties.In the present work evaluate the influence of these two distinct processes to deagglomeration and the consequence in the particle size of the β-TCP obtained through solid-state reaction. Among all of the routes used in research and industry to reduce the particles size of different materials, the high energy ball milling is one of the most effective, due to the high rotation speed that this process achieves. The deagglomeration through agate mortar is considered a cheaper process when compared with the high energy ball milling. The characterization of both powders, deagglomerated in high energy ball milling and agate mortar, was realized through scanning electron microscopy, to analyze the powder morphology, and laser granulometry, to determine the size of the particles. Also, the forerunner powder was previously submitted to x-ray diffraction to confirm the formation of the β-TCP phase. The analysis through x-ray diffraction confirmed that the phase formed during the calcination process corresponded to the β-TCP. The results obtained after the deagglomeration processes indicated that the morphology was predominantly irregular for both powders. In relation to the granulometry, the deagglomeration performed through agate mortar showed to produce particles with smaller size (11,4µm e 0,9µm) and heterogeneous distribution, while the high energy ball milling process produced particles with larger size (11,4µm a 1,8µm) and higher homogeneity.

High-Energy Ball Milling and Sintering of Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B Powders Mixtures

2014 ◽  
Vol 802 ◽  
pp. 20-24 ◽  
Author(s):  
Lucas Moreira Ferreira ◽  
Luciano Braga Alkmin ◽  
Érika C.T. Ramos ◽  
Carlos Angelo Nunes ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Equilibrium Structures ◽  
Rotary Speed ◽  
Steel Balls

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.

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