scholarly journals Microstructural Stability of Ti based Composites Fabricated by Spark Plasma Sintering

2020 ◽  
Vol 321 ◽  
pp. 03023
Author(s):  
Yoshimi Watanabe ◽  
Miwa Hattori ◽  
Tadachika Chiba ◽  
Hisashi Sato
Keyword(s):  
Spark Plasma Sintering ◽  
Heterogeneous Nucleation ◽  
Elevated Temperatures ◽  
Nucleation Site ◽  
Layer By Layer ◽  
Microstructural Stability ◽  
Heterogeneous Nucleation Site ◽  
Pinning Effect ◽  
Plasma Sintering ◽  
Spark Plasma

In our previous study, the effects of TiC heterogeneous nucleation site particles on formability and microstructure of additive manufactured (AMed) Ti-6Al-4V products were studied. It was found that the addition of TiC particles decreased the grain size of primary β phase in AMed Ti-6Al-4V samples, since TiC particles act as heterogeneous nucleation sites. It is also found that the density of AMed Ti-6Al-4V samples could be increased by addition of TiC particles. It is expected that solid-state β-grain growth by the high temperature thermal cycles associated with layer-by-layer manufacturing can be suppressed by the pinning effect of TiC heterogeneous nucleation site particles. In this study, the pinning effect of heterogeneous nucleation site particles on microstructure of Ti at elevated temperatures is studied. For this purpose, Ti-0.3vol%TiC samples fabricated by spark plasma sintering (SPS) are used as the model materials, and microstructure and hardness of the samples heat treated at elevated temperatures are studied.

MICROSTRUCTURE AND MECHANICAL BEHAVIOR OF AMORPHOUS Al–Cu–Ti METAL FOAMS SYNTHESIZED BY SPARK PLASMA SINTERING

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850022
Author(s):  
MAOYUAN LI ◽  
LIN LU ◽  
ZHEN DAI ◽  
YIQIANG HONG ◽  
WEIWEI CHEN ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Metal Foams ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Xrd Patterns

Amorphous Al–Cu–Ti metal foams were prepared by spark plasma sintering (SPS) process with the diameter of 10[Formula: see text]mm. The SPS process was conducted at the pressure of 200 and 300[Formula: see text]MPa with the temperature of 653–723[Formula: see text]K, respectively. NaCl was used as the space-holder, forming almost separated pores with the porosity of 65 vol%. The microstructure and mechanical behavior of the amorphous Al–Cu–Ti metal foams were systematically investigated. The results show that the crystallinity increased at elevated temperatures. The effect of pressure and holding time on the crystallization was almost negligible. The intermetallic compounds, i.e. Al–Ti, Al–Cu and Al–Cu–Ti were identified from X-ray diffraction (XRD) patterns. It was found that weak adhesion and brittle intermetallic compounds reduced the mechanical properties, while lower volume fraction and smaller size of NaCl powders improved the mechanical properties.

Formation of Metal-Intermetallic Laminate Composites by Spark Plasma Sintering of Metal Plates and Powder Work Pieces

2014 ◽  
Vol 698 ◽  
pp. 277-282 ◽  
Author(s):  
Daria V. Lazurenko ◽  
Vyacheslav I. Mali ◽  
Alexander Thoemmes
Keyword(s):  
Spark Plasma Sintering ◽  
Titanium Aluminide ◽  
Elevated Temperatures ◽  
Intermetallic Layer ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
Laminate Composites ◽  
Plasma Sintering ◽  
Metal Plates ◽  
Spark Plasma

Laminate composites with an intermetallic component are some of the most prospective constructional and functional materials. The basic formation method of such materials consists in heating a stack composed of metallic plates reacting at elevated temperatures to form intermetallic phases. The temperature of the process is usually approximately equal to a melting point of a more easily fusible component. In this study, an alternative technology of producing a titanium – titanium aluminide composite with a laminate structure is suggested. It consists in combining metallic (titanium and aluminum) powder mixtures pre-sintered at 400 оС with titanium plates, alternate stacking of these components and subsequent spark plasma sintering (SPS) of the fabricated workpieces. Applying this technology allowed for the fabrication of metal-intermetallic laminate (MIL) materials with an inhomogeneous structure of intermetallic interlayers. The phases revealed in the composite by X-Ray diffraction (XRD) were α-Ti, Al, Al3Ti and Al2Ti. Moreover, the results of the energy-dispersive analysis gave the evidence of the formation of Ti-enriched phases in powder layers after SPS. A small number of voids were observed between the structural components of the intermetallic layers. Voids were also detected at “metal-intermetallic” interfaces; however, the quality of connection between different layers in the composite was very high. The microhardness of an intermetallic layer formed in the composite was comparable to the microhardness of the Al3Ti compound. The microhardness of titanium was equal to 1600 MPa.

scholarly journals Tribological Characterization of Micron-/Nano-Sized WC-9%Co Cemented Carbides Prepared by Spark Plasma Sintering at Elevated Temperatures

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 920 ◽  
Author(s):  
Saleh Wohaibi ◽  
Abdul Mohammed ◽  
Tahar Laoui ◽  
Abbas Hakeem ◽  
Akeem Adesina ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Normal Load ◽  
Cemented Carbide ◽  
Plasma Sintering ◽  
Dry Conditions ◽  
Spark Plasma ◽  
Track Area

The present study investigates the high temperature tribological performance of spark plasma sintered, nano- and micron-sized tungsten carbide (WC) bonded by 9 wt.% cobalt (Co). The composites were fabricated using a two-step procedure of mixing followed by spark plasma sintering (SPS). Ball-on-disc wear tests were conducted at a normal load of 30 N, linear speed of 0.1 m/s under dry conditions and at three different temperatures (room temperature, 300 °C and 600 °C). Field emission scanning electron microscopy (FESEM), optical profilometry and energy dispersive X-ray (EDS) spectroscopy were used to analyze the surface morphology and the wear track area. At room temperature, it was observed that the nano-sized WC composites exhibited better wear resistance than the micron-sized WC composites. The wear resistance of the nano-sized samples declined significantly relative to that of the micron-sized samples with an increase in temperature. This decline in performance was attributed to the higher surface area of nano-sized WC particles, which underwent rapid oxidation at elevated temperatures, resulting in poor wear resistance. The wear rate observed at 600 °C for the micron-sized WC composites was 75% lower than that of the nano-sized cemented carbide. Oxidative wear was observed to be the predominant wear mechanism for both cemented carbide samples at elevated temperatures.

High Temperature Microstructural Stability of Si3N4 in TiAl Alloys

2007 ◽  
Vol 534-536 ◽  
pp. 1577-1580
Author(s):  
Jee Hoon Choi ◽  
Dong Bok Lee
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Reaction Layer ◽  
Microstructural Stability ◽  
Tial Alloys ◽  
Plasma Sintering ◽  
The Matrix ◽  
Spark Plasma

Alloys of Ti-50 at.% Al with (3 and 10)wt.% Si3N4 particles were prepared by a mechanical alloying-spark plasma sintering (MA-SPS) method. The matrix consisted primarily of TiAl, Ti2AlN, TiN. Si3N4 was unstable in the matrix and started to decompose forming a Ti5Si3 reaction layer on the surface of former Si3N4 particles during sintering and heat treatment at 1373 K.

Preparation of Bulk Graphene Nanoplatelets by Spark Plasma Sintering — Electrical and Thermal Properties

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660003 ◽  
Author(s):  
Mattipally Prasad ◽  
Tata N. Rao ◽  
P. S. R. Prasad ◽  
D. Suresh Babu
Keyword(s):  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
Extreme Temperature ◽  
Ceramic Matrix Composites ◽  
Lattice Parameter ◽  
Graphene Nanoplatelets ◽  
Matrix Composites ◽  
Thermal Expansion Coefficients ◽  
Plasma Sintering ◽  
Spark Plasma

Consolidation of graphene nanoplatelets (GNPs) by spark plasma sintering (SPS) to study the feasibility of its structure retention at extreme temperature and pressure conditions. Structural characterization of the GNP powder and pellet were carried out by Micro-Raman, SEM, and TEM. HT-XRD. A.C. and D.C. conductivity of GNP pellet is carried out at room temperature. GNPs survived its structure in the SPS processing at an extreme temperature of 1850[Formula: see text]C and uni-axial pressure 60[Formula: see text]MPa, vacuum at [Formula: see text] Torr. Our study shows the potential for GNPs to be successfully used as a reinforcing in ceramic matrix composites using SPS. The diffraction has been accurately calibrated to waterfall the shift in 2[Formula: see text] values at elevated temperatures. The corrected lattice parameter data have been used to estimate the instantaneous and mean thermal expansion coefficients as a function of temperature. The lattice parameters “[Formula: see text]” and “[Formula: see text]” for powder and pellet GNP is found to be 0.2456(1)[Formula: see text]nm and 0.6700(2)[Formula: see text]nm, respectively. The thermal expansivity of GNP powder and pellet along “[Formula: see text]”- and “[Formula: see text]”-axis are found to be [Formula: see text][Formula: see text]K[Formula: see text], [Formula: see text][Formula: see text]K[Formula: see text] and [Formula: see text][Formula: see text]K[Formula: see text], [Formula: see text][Formula: see text]K[Formula: see text], respectively. Electrical conductivity of GNP pellet is found to be 5700[Formula: see text]S/m.

Influence of Oxide Dispersoids on the Structure Development of Copper Nanocomposite Prepared by Spark Plasma Sintering Technology

2020 ◽  
Vol 405 ◽  
pp. 391-395
Author(s):  
Juraj Szabo ◽  
Katarína Ďurišinová ◽  
Ondrej Milkovič ◽  
Juraj Ďurišin
Keyword(s):  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
Nano Particles ◽  
Processing Route ◽  
Sintered Compact ◽  
Practical Utilization ◽  
Ultrafine Grains ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Thermal Stable

Dispersion strengthened Cu composites are studied over recent years to find an optimum processing route to obtain a high strength, thermal-stable copper alloy designed for modern applications in electrical engineering. The experimental Cu–4Al2O3–1MgO material was prepared by in situ thermo-chemical technique and mechanical milling followed by spark plasma sintering (SPS). The study analyses the influence of the Al2O3 and MgO secondary phases on strengthening the copper matrix. Microstructure of the composite was studied by X-ray diffraction analysis, scanning and transmission electron microscopy. The sintered microstructure shows a grain size distribution characterized by ultrafine grains/twins embedded inside the matrix of nanocrystalline grains. The microstructure is thermal stable up to 900 °C due to the dispersed alumina nano-particles that effectively strengthen crystallite/grain boundaries during the SPS process and annealing of the sintered compact at elevated temperatures. On the other hand, the coarsened MgO particles are responsible for ultrafine grains/twins formation. The obtained microstructure is important for practical utilization of the material because this structure is characterized by a good combination of strength and ductility.

Non-equiatomic W10Mo27Cr21Ti22Al20 high-entropy alloy produced by mechanical alloying and spark plasma sintering: Phase evolution and mechanical properties

2022 ◽  
pp. 146442072110510
Author(s):  
Hamed Naser-Zoshki ◽  
Ali-Reza Kiani-Rashid ◽  
Jalil Vahdati-Khaki
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
High Entropy Alloy ◽  
Solid Solution Phase ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma

In this work, non-equiatomic W10Mo27Cr21Ti22Al20 refractory high-entropy alloy (RHEA) was produced using mechanical alloying followed by spark plasma sintering. The phase formation, microstructure, and compressive mechanical properties of the alloy were studied. During mechanical alloying, a Body-centered cubic (BCC) solid solution phase with a particle size of less than 1 µm was obtained after 18 h ball milling. The microstructure of the sintered sample exhibits three distinct phases consisting of two solid solution phases BCC1 and BCC2 as well as fine TiCxOy precipitates distributed in them. The volume fractions of each phase were about 79%, 8%, and 13%, respectively. The sintered W10Mo27Cr21Ti22Al20 showed yield strengths of 2465, 1506, 405, and 290 MPa at room temperature 600, 1000, and 1200°C, respectively, which are about twice that of the same refractory high-entropy alloy produced by vacuum arc melting. At 1000 and 1200°C, the strength after yielding gradually increased to 970 and 718 MPa at a compressive strain of 60%. The studied refractory high-entropy alloy can have good potential in high-temperature applications due to its high specific strength at elevated temperatures compared to conventional Ni-based superalloys and most as-reported refractory high-entropy alloys.

scholarly journals Preparation of TiAl15Si15 alloy by High Pressure Spark Plasma Sintering

2018 ◽  
Vol 24 (2) ◽  
pp. 174
Author(s):  
Anna Knaislová ◽  
Pavel Novák ◽  
Filip Průša ◽  
Sławomir Cygan ◽  
Lucyna Jaworska
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Powder Metallurgy ◽  
Spark Plasma Sintering ◽  
Elevated Temperatures ◽  
Reactive Sintering ◽  
Compact Sample ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Method

<p class="AMSmaintext"><span lang="EN-GB">This work deals with preparation of intermetallic alloy TiAl15Si15 (wt. %) by powder metallurgy using Spark Plasma Sintering method. Ti-Al-Si alloys are known as materials with low density, relatively good mechanical properties in comparison with their density and good oxidation and corrosion resistance at elevated temperatures. Preparation of intermetallics by melting metallurgy is very problematic. Powder metallurgy using reactive sintering followed by suitable compaction seems to be a promising method. In this work, TiAl15Si15 alloy was prepared by reactive sintering, milling and by unique ultra-high pressure Spark Plasma Sintering within the framework of international cooperation in Krakow. For the comparison it was also prepared by conventional Spark Plasma Sintering. The results show that higher pressure of sintering decreases the porosity of compact sample and increases mechanical properties, especially hardness.</span></p>

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