scholarly journals Mechanical Alloying of Elemental Powders into Nanocrystalline (NC) Fe-Cr Alloys: Remarkable Oxidation Resistance of NC Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 695
Author(s):  
R. K. Singh Raman
Keyword(s):  
Mechanical Alloying ◽  
Ball Milling ◽  
Oxidation Resistance ◽  
Thermal Processing ◽  
Nanocrystalline Alloy ◽  
Cost Effective ◽  
Mechanically Alloyed

Mechanical alloying is among the few cost effective techniques for synthesizing nanocrystalline alloy powders. This article reviews mechanical alloying or ball-milling of (NC) powders of Fe-Cr alloys of different compositions, and the remarkable oxidation resistance of the NC alloy. The article also reviews challenges in thermal processing of the mechanically alloyed powders (such as compaction into monolithic mass) and means to overcome the challenges.

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.

DEVELOPMENT AND CHARACTERIZATION OF SiC–Al2O3–Al CERAMIC MATRIX NANOCOMPOSITE POWDER

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350059 ◽  
Author(s):  
MARYAM KARBASI ◽  
MEHDI RAZAVI ◽  
MINA AZADI ◽  
LOBAT TAYEBI
Keyword(s):  
Mechanical Alloying ◽  
Ball Milling ◽  
Cost Effective ◽  
Ceramic Matrix ◽  
Mechanochemical Reaction ◽  
Nanocomposite Powder ◽  
Crystallite Sizes ◽  
Method Of Production ◽  
Commercial Applications ◽  
Matrix Nanocomposite

In this study, SiC – Al 2 O 3– Al ceramic matrix nanocomposite powder was successfully synthesized employing mechanical alloying technique, through mechanochemical reaction among Silicon dioxide (SiO2), Carbon (C) and Aluminum (Al). For the commercial purposes, the materials ( SiO 2, C and Al powders) and also the method of synthesis (mechanical alloying) is considered to be cost effective for the production of SiC – Al 2 O 3– Al nanocomposite. Addition of alumina ( Al 2 O 3) and aluminum to silicon carbide (SiC) in a nancomposite form can improve the fracture toughness, strength and fatigue crack resistance of SiC and make it a leading material for many commercial applications specially by considering the cost-effective method of production. The structural evaluation of powder particles after different milling times was conducted by X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The results showed that during ball milling the SiO 2, C and Al reacted with a combustion mode producing SiC – Al 2 O 3– Al nanocomposite after 24 h ball milling and annealing at the temperature of 920°C. The crystallite sizes of phases remained in nanometric scale after annealing at 920°C for 1 h. Based on our investigation, it was revealed that ball milling and annealing process decreases the temperature of reaction between SiO 2 and C from 1500°C to 920°C.

scholarly journals Iron-based intermetallic particles formation in Al-Zn-Si alloy through powder metallurgy route

2021 ◽  
Vol 8 (12) ◽  
pp. 36-42
Author(s):  
Khaliq et al. ◽  
Keyword(s):  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Cold Pressing ◽  
X Ray ◽  
Steel Strips ◽  
Intermetallic Particles ◽  
Powder Metallurgy Route

Corrosion of the steel products is one of the significant challenges which is managed by coating with Al-Zn-based alloys. The Galvalume alloy (Al-55%, 43.5%-Zn, Si-1.5%) is coated on steel strips via a hot-dipping process. The dissolution of iron (Fe) from steel strips and the formation of Fe-based intermetallic particles is an inevitable phenomenon during the hot-dip coating process. These intermetallic particles are a primary source of massive bottom dross build-up in the coating pot and metal spot defects in the coated steel products. Therefore, it is important to investigate the formation of Fe-based intermetallic particles. In this study, Fe-based intermetallic particles are produced via the powder metallurgy route. High energy ball milling was used for mechanical alloying of aluminum (Al), iron (Fe), silicon (Si), and zinc (Zn) powders. Optimized ball milling conditions were identified after a series of trials. After cold pressing, the mechanically alloyed samples (pellets) were sintered at various conditions in a high vacuum sintering furnace. The X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy-dispersive X-ray diffraction (EDS) were used for the analysis of raw material, mechanically alloyed powders, and sintered pellets. It is concluded that the mechanical alloying of 6h and cold pressing at 9 tons for 30 min is sufficient to produce a dense compact material. It was found that Fe-based intermetallic particles were successfully fabricated which were α-AlFeSi. However, intermetallic particles similar to those found in the bottom dross of the coating pot are difficult to fabricate through the powder metallurgy route due to the volatilization of Zn during the sintering process.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF TiB2 NANOCRYSTALLINE POWDER BY MECHANICAL ALLOYING

2012 ◽  
Vol 05 ◽  
pp. 204-211 ◽  
Author(s):  
MAHBOOBEH MOALLEM ◽  
MOHAMMAD HASAN ABBASI ◽  
FATHOLLAH KARIM ZADEH
Keyword(s):  
Grain Size ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Lattice Strain ◽  
Structural Evolution ◽  
Nanocrystalline Powder ◽  
Combustion Mechanism ◽  
Mechanically Alloyed ◽  
Xrd Patterns

In this investigation, TiB 2 nanocrystalline powder was synthesized by mechanical alloying of the elemental mixture of Ti and B powders in argon atmosphere. In order to study the structural evolution of the powder during ball milling, X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used. Adiabatic temperature calculations were performed for characterization of TiB 2 powder. Also, the effects of heat treatment on the structural evolution and thermal stability of mechanically alloyed powders were investigated. It was found from the XRD patterns that TiB 2 was formed via combustion mechanism. By increasing milling time, the grain size decreased while the lattice strain increased. SEM micrographs showed that TiB 2 particles were spherical. The grain size and lattice strain reached 24 nm and 1.8% respectively, after 60 hours ball milling.

Magnetic and Thermal Studies of Iron-Based Amorphous Alloys Produced by a Combination of Melt-Spinning and Ball Milling

2021 ◽  
Vol 1163 ◽  
pp. 99-105
Author(s):  
Zahra Allafe Razzaghi ◽  
Abbas Kianvash ◽  
Abolfazl Tutunchi
Keyword(s):  
Particle Size ◽  
Mechanical Alloying ◽  
Ball Milling ◽  
Melt Spinning ◽  
Thermal Studies ◽  
Average Particle Size ◽  
Ferromagnetic Behavior ◽  
Average Particle ◽  
Mechanically Alloyed ◽  
Melt Spun

In this study, we demonstrate the synthesis of an Fe78Si9B10P3 amorphous alloy by three pathways: mechanical alloying, melt-spinning and a combination of melt-spinning and ball milling. Microstructure, thermal stability and soft magnetic properties of the melt-spun and mechanically alloyed powders are comparatively studied. Ball milling of previously melt-spun samples led to an amorphous powder with an average particle size of ~2.4 μm after 20 hrs of milling. Mechanical alloying of elemental Fe-Si-B-P powders in a planetary ball mill for up to 100 hrs led only to a partial amorphisation of powder with a median particle size of ~1.3 μm. Differential thermal analysis of the amorphous ribbon revealed that the amorphous phase was stable up to ~520 °C, at which the crystallization process occurred. The melt spun ribbons exhibited excellent soft ferromagnetic behavior, including high saturation magnetization (Ms) of ~171 emu/g and a low coercivity (Hc) of ~2.8 Oe. In the 20 hrs milled ribbons, due to a probable partial anisotropy which induced by ball milling stress, the Ms value decreased slightly to ~161 emu/g but the Hc increased to ~38 Oe. The mechanically alloyed samples present a relatively lower Ms of ~154 emu/g and higher Hc of ~43 Oe. It is to be noted that the milling of ribbons is usually inevitable due to their technological restrictions in use.

Microstructure of mechanically alloyed and hot-pressed Al5CuZr2

1990 ◽  
Vol 48 (4) ◽  
pp. 970-971
Author(s):  
T. E. Mitchell ◽  
P. B. Desch ◽  
R. B. Schwarz
Keyword(s):  
Mechanical Alloying ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Rapid Quenching ◽  
Hardened Steel ◽  
Alloyed Powder ◽  
Ion Milling ◽  
Mechanical Grinding ◽  
Mechanically Alloyed ◽  
Steel Container

Al3Zr has the highest melting temperature (1580°C) among the tri-aluminide intermetal1ics. When prepared by casting, Al3Zr forms in the tetragonal DO23 structure but by rapid quenching or by mechanical alloying (MA) it can also be prepared in the metastable cubic L12 structure. The L12 structure can be stabilized to at least 1300°C by the addition of copper and other elements. We report a TEM study of the microstructure of bulk Al5CuZr2 prepared by hot pressing mechanically alloyed powder.MA was performed in a Spex 800 mixer using a hardened steel container and balls and adding hexane as a surfactant. Between 1.4 and 2.4 wt.% of the hexane decomposed during MA and was incorporated into the alloy. The mechanically alloyed powders were degassed in vacuum at 900°C. They were compacted in a ram press at 900°C into fully dense samples having Vickers hardness of 1025. TEM specimens were prepared by mechanical grinding followed by ion milling at 120 K. TEM was performed on a Philips CM30 at 300kV.

ROLLED ALLOYS HR-120

Alloy Digest ◽  
2000 ◽  
Vol 49 (10) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Thermal Processing ◽  
Hot Corrosion ◽  
Heat Treating ◽  
Temperature Performance

Abstract HR-120 alloy is an alloy designed for thermal processing. It possesses excellent strength, oxidizing hot corrosion resistance, good carburization resistance, and oxidation resistance through 1093 deg C (2000 deg F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-561. Producer or source: Rolled Alloys.

New Fe-Ni Based Metal-Metalloid Glassy Alloys Prepared by Mechanical Alloying and Rapid Solidification

1996 ◽  
Vol 455 ◽  
Author(s):  
J. J. Suñol ◽  
M. T. Clavaguera-Mora ◽  
N. Clavaguera ◽  
T. Pradell
Keyword(s):  
Mechanical Alloying ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Magnetic Interaction ◽  
Processing Route ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Glassy Alloys ◽  
Rapidly Solidified ◽  
Thermal Stability Of

ABSTRACTMechanical alloying and rapid solidification are two important routes to obtain glassy alloys. New Fe-Ni based metal-metalloid (P-Si) alloys prepared by these two different processing routes were studied by differential scanning calorimetry and transmission Mössbauer spectroscopy. Mechanical alloyed samples were prepared with elemental precursors, and different nominal compositions. Rapidly solidified alloys were obtained by melt-spinning. The structural analyses show that, independent of the composition, the materials obtained by mechanical alloying are not completely disordered whereas fully amorphous alloys were obtained by rapid solidification. Consequently, the thermal stability of mechanically alloyed samples is lower than that of the analogous material prepared by rapid solidification. The P/Si ratio controls the magnetic interaction of the glassy ribbons obtained by rapid solidification. The experimental results are discussed in terms of the degree of amorphization and crystallization versus processing route and P/Si ratio content.

scholarly journals Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
Nominal Composition ◽  
Mechanically Alloyed ◽  
Milling Parameters ◽  
Energy Ball ◽  
Full Conversion

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.

Processing and Excellent Oxidation Resistance of Nanocrystalline Fe-Cr Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 1122-1125
Author(s):  
Rajeev K. Gupta ◽  
B.V. Mahesh ◽  
R.K. Singh Raman ◽  
Carl C. Koch
Keyword(s):  
Oxidation Resistance ◽  
Secondary Ion Mass Spectrometry ◽  
Nanocrystalline Alloy ◽  
High Energy ◽  
Processing Route ◽  
Protective Oxide ◽  
Time Intervals ◽  
Regular Time ◽  
Order Of Magnitude ◽  
Energy Ball

Nanocrystalline and microcrystalline Fe-10Cr alloys were prepared by high energy ball milling followed by compaction and sintering, and then oxidized in air for 52 hours at 400°C. The oxidation resistance of nanocrystalline Fe-10Cr alloy as determined by measuring the weight gain after regular time intervals was compared with that of the microcrystalline alloy of same chemical composition (also prepared by the same processing route and oxidized under identical conditions). Oxidation resistance of nanocrystalline Fe10Cr alloy was found to be in excess of an order of magnitude superior than that of microcrystalline Fe10Cr alloy. The paper also presents results of secondary ion mass spectrometry of oxidized samples of nanocrystalline and microcrystalline Fe-Cr alloys, evidencing the formation of a more protective oxide scale in the nanocrystalline alloy.

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