Microhardness Enhancement in Fully Dense Fe-Based Nanophase Metallic Alloys

1995 ◽  
Vol 400 ◽  
Author(s):  
L. He ◽  
E. Ma
Keyword(s):  
Grain Size ◽  
High Energy ◽  
Metallic Alloys ◽  
Full Density ◽  
Strengthening Effect ◽  
Two Phase ◽  
Grain Sizes ◽  
Sinter Forging ◽  
Interphase Boundaries ◽  
Energy Ball

AbstractNano-grained Fe-29Al-2Cr intermetallic and Fe-Cu two-phase composites have been consolidated to full density from powders produced by high-energy ball milling, using a sinter forging procedure developed recently in our laboratory. Grain sizes remained within nanophase range (<100 nm) after consolidation. Microhardness tests of Fe-29Al-2Cr samples consolidated to different density levels indicate a significant strengthening effect due to nanoscale grain size and a monotonic microhardness increase with decreasing residual porosity. Fully dense Fe-Cu composites exhibit enhanced microhardness as compared with rule-of-mixtures predictions, which may be attributable to interface strengthening at fcc-bcc interphase boundaries.

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.

Full-density nanocrystalline Fe–29Al–2Cr intermetallic consolidated from mechanically milled powders

1996 ◽  
Vol 11 (1) ◽  
pp. 72-80 ◽  
Author(s):  
L. He ◽  
E. Ma
Keyword(s):  
Grain Size ◽  
Mechanical Milling ◽  
Hot Forging ◽  
Full Density ◽  
Strengthening Effect ◽  
Practical Applications ◽  
Size Refinement ◽  
Sinter Forging ◽  
Average Grain Size ◽  
Milled Powders

Fe–29Al–2Cr powders with nanoscale grain sizes were produced by mechanical milling of prealloyed intermetallic powders. A consolidation procedure employing high-pressure, low strain rate hot forging (sinter-forging) has been developed to consolidate the powders into full-density compacts. The relative density and average grain size of the compact have been studied as a function of consolidation temperature at constant pressure. Fully dense compacts (>99.5% theoretical density) were produced at a relatively low temperature of 545°C with a pressure of 1.25 GPa. Transmission electron microscopy and x-ray diffraction analysis indicate that the average grain size has been maintained to the order of 30 nm in samples consolidated under these conditions. By using protective Ar atmosphere during mechanical milling and consolidation, contamination of oxygen and carbon in consolidated samples has been controlled to below a small fraction of an atomic percent. Microhardness tests of nanocrystalline Fe–29Al–2Cr samples indicate a significant strengthening effect due to grain size refinement and a monotonic hardness increase with decreasing residual porosity. Our work demonstrates the feasibility of using mechanically milled powders as the source of nanocrystalline materials for the production of fully dense, low-impurity, nanocrystalline bulk samples needed for reliable mechanical property measurements and practical applications.

scholarly journals Influence of mechanical activation of AL2O3 on synthesis of magnesium aluminate spinel

2004 ◽  
Vol 36 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Zhang Zhihui ◽  
LI. Nan
Keyword(s):  
Grain Size ◽  
Mechanical Activation ◽  
Bulk Density ◽  
Milling Time ◽  
High Energy ◽  
Magnesium Aluminate ◽  
Reaction Sintering ◽  
Air Atmosphere ◽  
Energy Ball ◽  
Analytical Reagent

Magnesium aluminate (MA) spinel is synthesized by reaction sintering from alumina and magnesia. The effects of mechanical activation of Al2O3 on reaction sintering were investigated. Non-milled a - Al2O3 and a - Al2O3 high-energy ball milled for 12h, 24h and 36h were mixed with a MgO analytical reagent according to the stoichiometric MA ratio, respectively and pressed into billets with diameters of 20mm and height of 15mm. The green-body billets were then sintered at high temperature in an air atmosphere. The results show that bulk density, relative content of MA and grain size of MA increase with increasing high-energy ball milling time of Al2O3. However prolonged milling time over 24h has a small beneficial effect on the densification of MA. Bulk density and grain size of a sample of a- Al2O3 milled for 24h are 3.30g/cm3 and 4-5 mm, respectively.

Phase development during high-energy ball-milling of zinc oxide and iron – the impact of grain size on the source and the degree of contamination

2015 ◽  
Vol 44 (43) ◽  
pp. 18870-18881 ◽  
Author(s):  
G. Štefanić ◽  
S. Krehula ◽  
I. Štefanić
Keyword(s):  
Grain Size ◽  
Zinc Oxide ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Degree Of Contamination ◽  
Phase Development ◽  
Energy Ball ◽  
The Impact

The impact of grain size on the source and the degree of contamination.

Investigation of Porosity and Mechanical Properties of Graphene Nanoplatelets Reinforced AlSi10Mg by Selective Laser Melting

2017 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Shiqiang Lu ◽  
Weihan Xiao
Keyword(s):  
Selective Laser Melting ◽  
Tensile Tests ◽  
High Energy ◽  
Material Strength ◽  
Strengthening Effect ◽  
Laser Melting ◽  
Tensile Performance ◽  
Energy Ball ◽  
High Flexibility ◽  
The Relationship

Graphene possesses many outstanding properties, such as high strengths, light weight, making it an ideal reinforcement for metal matrix composite (MMCs). Meanwhile, fabricating MMCs through laser assisted additive manufacturing (LAAM) has attracted much attention in recent years due to the advantages of low waste, high precision, short production lead time, and high flexibility. In this study, graphene reinforced aluminum alloy AlSi10Mg is fabricated using selective laser melting. Composite powder is prepared using high-energy ball milling. Room temperature tensile tests are conducted to evaluate the tensile properties. Scanning electron microscopy (SEM) observations are conducted to investigate the microstructure and fracture surface of obtain composite. It is found that adding GNPs significantly increases porosity and therefore deteriorates material tensile performance. The relationship between porosity and material strength are numerically investigated. Taking into consideration the strength reduction caused by large porosity, the strengthening effect of GNPs turns out to be significant, which reaches 60.2 MPa.

Effect of Al(OH)3 in Enhancing PbSnF4 Anode Performances for Rechargeable Lithium-Ion Battery

2015 ◽  
Vol 245 ◽  
pp. 153-158 ◽  
Author(s):  
Denis P. Opra ◽  
Anatoly B. Podgorbunsky ◽  
Sergey V. Gnedenkov ◽  
Sergey L. Sinebryukhov ◽  
Alexander A. Sokolov ◽  
...  
Keyword(s):  
Aluminum Hydroxide ◽  
Specific Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
Li Ion Batteries ◽  
Two Phase ◽  
Milling Method ◽  
Energy Ball ◽  
Li Ion ◽  
Initial Capacity

Two-phase Al(OH)3–PbSnF4 composites (concentrations of aluminum hydroxide are equal to 5 wt.%, 15 wt.% and 30 wt.%) has been prepared by high-energy ball-milling method. The materials were employed as anodes in Li-ion batteries. It was established that PbSnF4-based systems yield high initial capacity of 800–1100 mAh g–1. The reversible specific capacity of Al(OH)3–PbSnF4 (aluminum hydroxide – 15 wt.%) after 10-fold charge–discharge cycling in the range of 2.5–0.005 V attains 120 mAh g–1, while the specific capacity of pure PbSnF4 is equal only to 20 mAh g–1. It has been shown that the deviation from 15 wt.% concentration of Al (OH)3 decreases cycling stability of lead fluorostannate (II).

Structural Evolution of Fe-50Al/WC Composite Powder During Mechanical Alloyed Process

2013 ◽  
Vol 441 ◽  
pp. 3-6
Author(s):  
Hong Tao Wang ◽  
Ruo Yu Wang ◽  
Xiao Chen ◽  
Xiao Bo Bai ◽  
Zeng Xiang Dong ◽  
...  
Keyword(s):  
Grain Size ◽  
Composite Powder ◽  
Milling Time ◽  
Structural Evolution ◽  
Annealing Treatment ◽  
High Energy ◽  
Intermetallic Matrix ◽  
Intermetallic Matrix Composite ◽  
Energy Ball ◽  
Thermal Stability Of

In the present study, Fe-50at%Al/WC intermetallic matrix composite powder was produced through mechanical alloying (MA) followed by annealing treatment. The phase transformations, grain size, microstructure and thermal stability of the composite powder during milling and annealing treatment were studied. The results showed that a bcc Fe(Al) solid solution reinforced with nanoscale WC particles was formed through high-energy ball milling The grain size of Fe(Al) decreased and the lattice strain of Fe(Al) increased with increasing milling time. The as-milled Fe(Al)/WC composite powder had lamellar structure. The oxygen content of Fe(Al)/WC composite powder increased with increasing milling time. The phase transformation from Fe(Al) to Fe-Al intermetallic phases was related to the milling time of composite powder and could occure at temperature of 400°C.

A Study of Pb (Zr0.52Ti0.48)O3 Ceramic Properties via High Energy Ball Mill

2015 ◽  
Vol 1087 ◽  
pp. 223-226
Author(s):  
Shafiza Afzan Sharif ◽  
J.M. Juliewatty ◽  
W.A.W. Yusoff
Keyword(s):  
Perovskite Phase ◽  
High Energy ◽  
Soaking Time ◽  
Grain Sizes ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Higher Temperature ◽  
Ball Milling Technique ◽  
Xrd Patterns ◽  
The Relationship

Pb (Zr0.52Ti0.48)O3, (PZT) powder has been synthesized using high energy ball milling technique. The synthesized powders were characterized using XRD, SEM, Density, Porosity and Impedance Analyzer. XRD patterns show that the perovskite phase of PZT can be formed from the mixture of starting material after milling for 40 h. The grain sizes of the powder have been estimated to be 1-3 μm. The relationship between the microstructure of the PZT samples and sintering temperature has been discussed. Dense PZT (> 95 % theoretical density) with excellent dielectric properties was obtained when the pellet are sintered at higher temperature with shorter soaking time. The results show that the sample sintered at 1100 °C /1 h yields a clearly uniform grain size with the highest dielectric constant.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of WC-16TiC-xTaC-9Co Cemented Carbides

2012 ◽  
Vol 268-270 ◽  
pp. 340-343
Author(s):  
Chong Cai Zhang ◽  
Quan Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
High Energy ◽  
Cemented Carbides ◽  
Average Grain Size ◽  
Comprehensive Performance ◽  
Energy Ball ◽  
Average Size

In this paper, the WC-16TiC-xTaC-9Co and Co are mixed together preparing for WC, (W, Ti, Ta) C. By high-energy ball milling, the powder is cold isostatic pressed and vacuum sintered by 1410°C, 1430°Cand 1450°C.The physical properties and the micrographs of samples are detected. The main conclusions are as following: sintered samples have the best comprehensive performance at 1450°C, the density of the sample is 99.7% and the actual density is 10.91g/cm3. The hardness is 92.8 HRA and the transverse rupture strength (TRS) is 1100MPa. The grain size grows up obviously with the high temperature. The average grain size of WC is 0.7μm and the average size of (W, Ti, Ta)C is 3μm.

Spark Plasma Sintering of High-Energy Ball-Milled ZrB2 and HfB2 Powders with 20vol% SiC

2018 ◽  
Vol 941 ◽  
pp. 1990-1995
Author(s):  
Naidu V. Seetala ◽  
Cyerra L. Prevo ◽  
Lawrence E. Matson ◽  
Thomas S. Key ◽  
Ilseok I. Park
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
Micro Hardness ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball ◽  
Ball Milling Time

ZrB2 and HfB2 with incorporation of SiC are being considered as structural materials for elevated temperature applications. We used high energy ball milling of micron-size powders to increase lattice distortion enhanced inter-diffusion to get uniform distribution of SiC and reduce grain growth during Spark Plasma Sintering (SPS). High-energy planetary ball milling was performed on ZrB2 or HfB2 with 20vol% SiC powders for 24 and 48 hrs. The particle size distribution and crystal micro-strain were examined using Dynamic Light Scattering Technique and x-ray diffraction (XRD), respectively. XRD spectra were analyzed using Williamson-Hall plots to estimate the crystal micro-strain. The particle size decreased, and the crystal micro-strain increased with the increasing ball milling time. The SPS consolidation was performed at 32 MPa and 2,000°C. The SEM observation showed a tremendous decrease in SiC segregation and a reduction in grain size due to high energy ball milling of the precursor powders. Flexural strength of the SPS consolidated composites were studied using Four-Point Bend Beam test, and the micro-hardness was measured using Vickers micro-indenter with 1,000 gf load. Good correlation is observed in SPS consolidated ZrB2+SiC with increased micro-strain as the ball milling time increased: grain size decreased (from 9.7 to 3.2 μm), flexural strength (from 54 to 426 MPa) and micro-hardness (from 1528 to 1952 VHN) increased. The correlation is less evident in HfB2+SiC composites, especially in micro-hardness which showed a decrease with increasing ball milling time.

Sign in / Sign up

Export Citation Format

Share Document