Influence of Powder Particle Size Distribution on the Properties of Press-and-Sintered Titanium and Ti-6Al-4V Preforms

The potential to control the final properties, as measured by density, strength and microstructure, of press-and-sintered titanium and master alloy Ti-6Al-4V is investigated by designing and evaluating bimodal particle size distributions of the relevant powders. Ratios of 1/3, 2/3 and 1/1 by volume of coarse to fine powders, as determined by particle size peaks, were blended from -200 and -100 mesh commercially pure titanium powders and -200 mesh 60Al-40V master alloy powder, in the case of Ti-6Al-4V. The powder blends were uniaxially compacted at 350, 400 and 450 MPa, and the green specimens were sintered under high vacuum for two hours at 1300°C. The results support theoretical prediction of green and sintered density based on the ratio of the volume percentage of coarse to fine powder; green density increases as the ratio of coarse powder increases for both the pure and alloy titanium, while the sinter density similarly decreases for the pure titanium. Microstructural observations of the sintered specimens show that the pore size decreases, and the pore shape becomes more rounded, as the ratio of fine powder increases. In order to extend the study to find the optimal packing ratio, and potentially the optimal blend for densification, further refinement of the initial powder particle size distributions is needed.

Download Full-text

Magnetomechanical Properties Of Composite Materials With Giant Magnetostriction

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0311 ◽

2015 ◽

Vol 60 (3) ◽

pp. 1819-1824 ◽

Cited By ~ 2

Author(s):

A.E. Tomiczek ◽

R. Mech ◽

L. A. Dobrzański ◽

T. Tański

Keyword(s):

Particle Size ◽

Composite Materials ◽

Magnetic Energy ◽

Compressive Modulus ◽

Powder Particle Size ◽

Size Distributions ◽

Particle Size Distributions ◽

The Matrix ◽

Giant Magnetostriction ◽

Polyurethane Matrix

AbstractThe aim of this work was to observe the changes in the magnetomechanical properties of composite materials with different Tb0.3Dy0.7Fe1.9(Terfenol-D) powder particle-size distributions and varying volume fractions in the polyurethane matrix. The results show a direct relationship between the properties and the particle size of the Tb0.3Dy0.7Fe1.9powder: the increases in the particle-size distribution of the Tb0.3Dy0.7Fe1.9powder in the matrix amplify the magnetostrictive responses and the compressive modulus values. Moreover, it was found that the key role in efficiency of the transformation of magnetic energy into mechanical plays the initial compressing pre-stress.

Download Full-text

Microstructure and Mechanical Properties of an Advanced Nickel-Based Superalloy in the as-HIP Form

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.278.265 ◽

2011 ◽

Vol 278 ◽

pp. 265-270 ◽

Cited By ~ 14

Author(s):

J.R. May ◽

M.C. Hardy ◽

M.R. Bache ◽

David D. Kaylor

Keyword(s):

Heat Treatment ◽

Particle Size ◽

Crack Growth ◽

Powder Particle ◽

Size Fraction ◽

Fine Powder ◽

Powder Particle Size ◽

Particle Size Fraction ◽

Coarse Powder ◽

Nickel Based Superalloy

This study evaluates the suitability of as-hot isostatically pressed (HIP) RR1000 for non-critical applications in aero-engine components. RR1000, an advanced powder nickel-based superalloy, was developed for disc rotor components in aero-engines. For these critical applications, the consolidated alloy powder particles are extruded to break down carbide and oxide networks, known as prior particle boundaries (PPBs), and to refine the structure into a fine grain size for isothermal forging. In this study, hot isostatically pressed compacts, made from two different powder particle size fractions have been assessed following heat treatments below and above the gamma prime solvus temperature. A microstructural evaluation shows a greater degree of PPB decoration occurs in the finer powder particle size fraction. Following a super-solvus heat treatment these PPBs pin grain boundaries of the fine powder particle size compacts, whilst the reduction of PPB decoration in coarse powder particle compacts allows significant grain growth. Tensile test results of as-HIP RR1000 show, good yield strengths, ultimate tensile strengths and ductility, which are comparable with extruded and isothermal forged RR1000 disc material. Dwell crack propagation tests show that finer powder particle size compacts, which have received a sub-solvus heat treatment, give the highest crack growth rates; whilst the remaining material conditions show markedly improved crack growth resistance. In conclusion, as-HIP RR1000 demonstrates clear potential for use in non-critical applications, employing either powder particle size fraction used in this study subject to the appropriate solution heat treatment.

Download Full-text

Size characterization of selected food powders by five particle size distribution functions Caracterización del tamaño de partícula de alimentos en polvo mediante cinco funciones de distribuciones de tamaño

Food Science and Technology International ◽

10.1177/108201329700300507 ◽

1997 ◽

Vol 3 (5) ◽

pp. 361-369 ◽

Cited By ~ 17

Author(s):

H. Yan ◽

G.V. Barbosa-Cánovas

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Distribution Functions ◽

Powder Particle Size ◽

Size Distributions ◽

Corn Meal ◽

Particle Size Distributions ◽

Food Powders ◽

Food Powder

The properties of a food particulate system are highly dependent on its particle size distribution. The knowledge of this distribution is essential to the analysis of the handling, processing, and functionality of the food powder. Properly selected distribution functions are excellent tools with which to simplify and accurately describe the particle size distribution. The objectives of this study were to identify appropriate distribution functions for characterizing the particle size distribution of selected food powders. Granular sugar, corn meal and instant non-fat milk powder were clas sified into six or seven particle size cuts for each powder. The experimental data were fitted by five particle size distribution functions: (i) Gates-Gaudin-Schuhmann (GGS); ( ii) Rosin-Rammler (RR); (iii) Modified Gaudin-Meloy (MGM); (iv) Log-normal (LN); and ( v) modified beta (MB). These models were selected for their mathematical simplicity, adequate statistical properties and usefulness in describing other particulate systems similar to the food powders under considera tion. In all cases, it was found that the RR and MGM models were the best for the characteriza tion of all food powders considered, the LN and MB were best for sugar, and the GGS was suitable for corn meal. All five models should be considered for characterizing other food powder particle size distributions because all of them offer enough flexibility to properly describe particle size distributions for different types of food powders.

Download Full-text

Influence of Particle Size Distribution on the Consistency of High Permeability MnZn Ferrite

Materials Science Forum ◽

10.4028/www.scientific.net/msf.787.357 ◽

2014 ◽

Vol 787 ◽

pp. 357-361

Author(s):

Cheng Hai Chen ◽

Xiao Long Li ◽

Ling Zhang ◽

Yao Ying ◽

Li Qiang Jiang ◽

...

Keyword(s):

Particle Size ◽

Size Distribution ◽

Mass Production ◽

Sintering Temperature ◽

Fine Powder ◽

Size Distributions ◽

Particle Size Distributions ◽

High Permeability ◽

Mnzn Ferrite ◽

Electromagnetic Performance

High-permeability MnZn ferrite cores were sintered under various sintering temperatures and atmospheres by using powders of different particle size distributions. It has been found that electromagnetic performance of cores sintered from powders with finer particle size and narrower size distribution varies less upon the change of sintering temperature and atmosphere. This suggests that the permeability consistency of MnZn ferrite can be improved by using fine powder with better uniformity in mass production.

Download Full-text