scholarly journals Spark Plasma Sintered Si3N4/TiN Nanocomposites Obtained by a Colloidal Processing Route

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
L. A. Díaz ◽  
W. Solís ◽  
P. Peretyagin ◽  
A. Fernández ◽  
M. Morales ◽  
...  
Keyword(s):  
Glassy Phase ◽  
Mechanical Performance ◽  
Processing Route ◽  
Colloidal Processing ◽  
Nitridation Process ◽  
Plasma Sintering ◽  
Tin Nanoparticles ◽  
Colloidal Method ◽  
Spark Plasma ◽  
Thermal Nitridation

Ceramic Si3N4/TiN (22 vol%) nanocomposites have been obtained by Spark Plasma Sintering (SPS). Our colloidal processing route allows obtaining dispersed nanoparticles of TiN smaller than 50 nm avoiding the presence of agglomerates. The nanostructured starting powders were obtained by using a colloidal method where commercial Si3N4submicrometer particles were coated with anatase TiO2nanocrystals. A later nitridation process led to the formation of TiN nanoparticles on the surface of Si3N4. A second set of powders was prepared by doping the above defined powders with yttrium and aluminium precursors using also a colloidal method as sources of alumina and yttria. After thermal nitridation and SPS treatment, it has been found that the addition of oxides dopants improves the mechanical performance (KIC,σf) but increases the electrical resistivity and significantly reduces the hardness. This is due to the formation of a continuous insulating glassy phase that totally envelops the conductive TiN nanoparticles, avoiding the percolative contact between them. The combination of colloidal processing route and SPS allows the designing of tailor-made free glassy phase Si3N4/TiN nanocomposites with controlled microstructure. The microstructural features and the thermoelectrical and mechanical properties of both kinds of dense SPSed compacts are discussed in this work.

scholarly journals Powder Metallurgy Processing and Mechanical Properties of Controlled Ti-24Nb-4Zr-8Sn Heterogeneous Microstructures

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1626
Author(s):  
Benoît Fer ◽  
David Tingaud ◽  
Azziz Hocini ◽  
Yulin Hao ◽  
Eric Leroy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Ball Milling ◽  
Processing Route ◽  
Fine Grain ◽  
Plasma Sintering ◽  
3D Network ◽  
Spark Plasma ◽  
Powder Particles ◽  
Heterogeneous Microstructures

This paper gives some insights into the fabrication process of a heterogeneous structured β-metastable type Ti-24Nb-4Zr-8Sn alloy, and the associated mechanical properties optimization of this biocompatible and low elastic modulus material. The powder metallurgy processing route includes both low energy mechanical ball milling (BM) of spherical and pre-alloyed powder particles and their densification by Spark Plasma Sintering (SPS). It results in a heterogeneous microstructure which is composed of a homogeneous 3D network of β coarse grain regions called “core” and α/β dual phase ultra-fine grain regions called “shell.” However, it is possible to significantly modify the microstructural features of the alloy—including α phase and shell volume fractions—by playing with the main fabrication parameters. A focus on the role of the ball milling time is first presented and discussed. Then, the mechanical behavior via shear tests performed on selected microstructures is described and discussed in relation to the microstructure and the probable underlying deformation mechanism(s).

Preparation and Characterization of Alumina based TiNn and SiCn Composites

2002 ◽  
Vol 740 ◽  
Author(s):  
Mats Carlsson ◽  
Mats Johnsson ◽  
Annika Pohl
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Ceramic Composites ◽  
Processing Route ◽  
Nano Structure ◽  
Plasma Sintering ◽  
Water Based ◽  
Spark Plasma

ABSTRACTCeramic composites containing 2 and 5vol. % of nanosized commercially available TiN and SiC particles in alumina were prepared via a water based slurry processing route followed by spark plasma sintering (SPS) at 75 MPa in the temperature range 1200–1600°C. Some of the samples could be fully densified by use of SPS already after five minutes at 1200°C and 75 MPa. The aim was to control the alumina grain growth and thus obtain different nano-structure types. The microstructures have been correlated to some mechanical properties; e.g. hardness and fracture toughness.

TiPt HTSMA Produced by Spark Plasma Sintering of Elemental Powders

2013 ◽  
Vol 738-739 ◽  
pp. 579-583
Author(s):  
Silethelwe Chikosha ◽  
Hilda Kundai Chikwanda
Keyword(s):  
Spark Plasma Sintering ◽  
Processing Route ◽  
Potential Candidate ◽  
Jet Engines ◽  
Two Phase ◽  
Alternative Processing ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Added Benefit ◽  
Sintering Conditions

Titanium-platinum (Ti50Pt50) alloy has been identified as a potential candidate for high temperature shape memory alloy (HTSMA) applications such as actuators in jet engines. This work evaluates powder metallurgy as an alternative processing route with the added benefit that near net shaped components can be formed. Spark plasma sintering (SPS) of blended elemental titanium and platinum powders was carried out. The sintering conditions used were: temperatures ranging from 1200 to 1400 °C and sintering times ranging from 10 to 30 minutes. SEM with EDS, XRD and DSC were carried out to study the results. Results showed that SPS only achieved high density, but not homogenisation of the alloys. All sintering conditions resulted in formation of the martensitic TiPt phase of interest, together with some or all of the following phases: Ti, Ti3Pt, Ti4Pt3, Ti3Pt5 and Pt. Post sintering annealing treatments were carried out to homoginise the alloys at 1300 °C for times ranging from 5 to 15 hours. With sufficient annealing times a two phase microstructure was produced with TiPt as the majority matrix phase and Ti3Pt5 as the precipitate phase.

scholarly journals Solid-State Processing Route, Mechanical Behaviour, and Oxidation Resistance of TiAl Alloys

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Prince V. Cobbinah ◽  
Wallace R. Matizamhuka
Keyword(s):  
Temperature Deformation ◽  
Processing Route ◽  
High Oxygen Content ◽  
Tial Alloys ◽  
Ultrafine Grains ◽  
Plasma Sintering ◽  
Dynamic Recrystallisation ◽  
Ternary Element ◽  
Spark Plasma ◽  
State Processing

A primary challenge associated with TiAl alloys is their low ductility at room temperature. One approach to overcome this flaw is attaining ultrafine grains in the alloy’s final microstructure. The powder metallurgy (PM) processing route favours the synthesising of ultrafine grains in TiAl alloys. This paper features the mechanical alloying (MA) process and rapid consolidation through the spark plasma sintering (SPS) technique, which comprises the PM process. Furthermore, a second approach discussed covers microalloying TiAl alloys. An evaluation of the influence of high oxygen content is also presented, including the formation of α-Al2O3. A section of the review delves into the dynamic recrystallisation mechanisms involved in elevated temperature deformation of TiAl alloys. The final section highlights the efficacy of ternary element additions to TiAl alloys against oxidation.

Properties Improvement of Spark Plasma Sintered Ti-7Al-1Mo Ternary Alloy by TiN Nanoparticles Addition

2021 ◽  
Vol 55 ◽  
pp. 150-158
Author(s):  
Samson Olaitan Jeje ◽  
Mxolisi Brendon Shongwe ◽  
Azeez Lawan Rominiyi ◽  
Peter Apata Olubambi
Keyword(s):  
Electron Microscopy ◽  
Yield Strength ◽  
Ternary Alloy ◽  
Lamellar Structure ◽  
Compressive Yield Strength ◽  
Weight Percentage ◽  
Β Phase ◽  
Plasma Sintering ◽  
Tin Nanoparticles ◽  
Spark Plasma

Titanium (Ti) alloys are materials of interest in structural and chemical applications due to their low density, outstanding mechanical and chemical resistance properties. However, the mechanical properties still need to be enhanced to make them suitable as a replacement for Ni-based superalloys. There have been significant breakthroughs in the reinforcement of Ti alloy with a small weight percentage (wt.%) of ceramics. This work investigates the effect of TiN nanoparticles’ addition on the densification, phase transformation, microstructure, hardness, and compressive properties of Ti-7Al-1Mo ternary alloy. 3 wt.% of TiN nanoparticles was blended with Ti-7Al-1Mo powder, and the resulting admixed powder was consolidated via spark plasma sintering technique at 50 MPa pressure, 10 min holding time, and 1000 °C temperature. Scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry were used to characterise the microstructure and phase composition respectively. The microstructure of Ti-7Al-1Mo revealed a lamellar structure with alpha (α) phase and minor beta (β) phase with visible grain boundaries, while TiN reinforced Ti-7Al-1Mo composite microstructure shows a bimodal structure with reduction in the lamellar structure. Ti-7Al-1Mo ternary alloy has a hardness value of 352±17 HV0.1 and a compressive yield strength of 985±31 MPa. The composite shows an increment of 74 HV and 323 MPa in its hardness and compressive yield strength respectively in comparison to the ternary alloy.

scholarly journals Effect of Short Attritor-Milling of Magnesium Alloy Powder Prior to Spark Plasma Sintering

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3973
Author(s):  
Peter Minárik ◽  
Mária Zemková ◽  
Michal Knapek ◽  
Stanislav Šašek ◽  
Jan Dittrich ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Spark Plasma Sintering ◽  
Alloy Powder ◽  
Mechanical Performance ◽  
Milled Powder ◽  
Plasma Sintering ◽  
Attritor Milling ◽  
Spark Plasma ◽  
Superior Mechanical Properties

The spark plasma sintering (SPS) technique was employed to prepare compacts from (i) gas-atomized and (ii) attritor-milled AE42 magnesium powder. Short attritor-milling was used mainly to disrupt the MgO shell covering the powder particles and, in turn, to enhance consolidation during sintering. Compacts prepared by SPS from the milled powder featured finer microstructures than compacts consolidated from gas-atomized powder (i.e., without milling), regardless of the sintering temperatures in the range of 400–550 °C. Furthermore, the grain growth associated with the increase in the sintering temperature in these samples was less pronounced than in the samples prepared from gas-atomized particles. Consequently, the mechanical properties were significantly enhanced in the material made of milled powder. Apart from grain refinement, the improvements in mechanical performance were attributed to the synergic effect of the irregular shape of the milled particles and better consolidation due to effectively disrupted MgO shells, thus suppressing the crack formation and propagation during loading. These results suggest that relatively short milling of magnesium alloy powder can be effectively used to achieve superior mechanical properties during consolidation by SPS even at relatively low temperatures.

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