Structural Transformations Occurring during the Formation of TiAl3-Based Composites Reinforced by TiB2 or TiC Hard Particles

2018 ◽  
Vol 769 ◽  
pp. 48-53
Author(s):  
Adelya A. Kashimbetova ◽  
Alexander Thoemmes ◽  
Ivan V. Ivanov
Keyword(s):  
Solid Solution ◽  
Intermetallic Compound ◽  
Elemental Analysis ◽  
Structural Transformations ◽  
Ceramic Powders ◽  
Hard Particles ◽  
Intermediate Layers ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Compound Tial

This work is devoted to investigation of the structure of Ti-TiAl3 composites reinforced by TiB2 or TiC hard particles and obtained by spark plasma sintering of elemental foils and ceramic powders. Sintering was carried out at the temperature of 830 oC under the pressure of 40 MPa during 10 minutes. Microstructure of the composites obtained was represented by alternated layers of titanium and intermetallic compound TiAl3. Also, it was found that at the Ti-TiAl3 interfaces thin intermediate layers were formed. Quantitative elemental analysis of these layers showed that Ti3Al, TiAl, and TiAl2 compounds, as well as Ti (Al) solid solution could be formed in these zones. Diffraction analysis did not reveal any transformations of initial reinforcing phases after sintering. Interlayers with titanium diboride had the average microhardness level of 3988 HV, and the average microhardness level of interlayers with TiC was 1610 HV.

scholarly journals Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

2021 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Group Iv ◽  
Hypersonic Vehicles ◽  
Metal Carbides ◽  
Initial Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

scholarly journals Refractory High-Entropy HfTaTiNbZr-Based Alloys by Combined Use of Ball Milling and Spark Plasma Sintering: Effect of Milling Intensity

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1268 ◽  
Author(s):  
Natalia Shkodich ◽  
Alexey Sedegov ◽  
Kirill Kuskov ◽  
Sergey Busurin ◽  
Yury Scheck ◽  
...  
Keyword(s):  
Solid Solution ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Vickers Hardness ◽  
High Energy ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball

For the first time, a powder of refractory body-centered cubic (bcc) HfTaTiNbZr-based high-entropy alloy (RHEA) was prepared by short-term (90 min) high-energy ball milling (HEBM) followed by spark plasma sintering (SPS) at 1300 °C for 10 min and the resultant bulk material was characterized by XRD and SEM/EDX. The material showed ultra-high Vickers hardness (10.7 GPa) and a density of 9.87 ± 0.18 g/cm³ (98.7%). Our alloy was found to consist of HfZrTiTaNb-based solid solution with bcc structure as a main phase, a hexagonal closest packed (hcp) Hf/Zr-based solid solution, and Me2Fe phases (Me = Hf, Zr) as minor admixtures. Principal elements of the HEA phase were uniformly distributed over the bulk of HfTaTiNbZr-based alloy. Similar alloys synthesized without milling or in the case of low-energy ball milling (LEBM, 10 h) consisted of a bcc HEA and a Hf/Zr-rich hcp solid solution; in this case, the Vickers hardness of such alloys was found to have a value of 6.4 GPa and 5.8 GPa, respectively.

Effects of Sintering Conditions on the Mechanical Properties of Alumina Particle Dispersed Magnesium SPS Compacts

2014 ◽  
Vol 783-786 ◽  
pp. 2433-2438 ◽  
Author(s):  
Shigehiro Kawamori ◽  
Hiroshi Fujiwara ◽  
Yukio Kasuga
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Alumina Particle ◽  
Applied Pressure ◽  
Powder Mixtures ◽  
Cooling Conditions ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Xrd And Tem ◽  
Main Factor

To enhance the mechanical properties of Mg alloys, 0-30vol% Al2O3/Mg powders were formed by ball milling powder mixtures of pure Mg and Al2O3 particles, and then Spark plasma sintering (SPS) compacts (Al2O3/Mg discs) were made by the Al2O3/Mg powders. The effect of the cooling conditions in the SPS process on the mechanical properties of the Al2O3/Mg discs was investigated. From the results of SEM, XRD and TEM-EDS, the microstructures of the Al2O3/Mg discs were identified to consist of α-Mg solid solution, Al2O3 particles, refined MgO particles and refined needle-like Mg17Al12 ( more than 20vol% Al2O3 content). The mechanical properties of the discs were able to control by the regulation of the cooling conditions (cooling rate (vc) and applied pressure in the cooling (pc)) in SPS process, and as a result, the SPS discs possessing the mechanical properties beyond HP compacts were obtained under the cooling conditions of “vc= 0.83K/sand pc = 20MPa”. Main factor that the cooling conditions in SPS process effect on the mechanical properties of the Al2O3/Mg discs are considered to be the compresive residual stress generated in the α - Mg solid solution by the thermal stress associated with deference of the coefficients of thermal expansion between the α - Mg and ceramics particles (Al2O3 and MgO) in the discs.

Microstructures and Mechanical Properties of Consolidated Mg-Zn-Y Alloy

2007 ◽  
Vol 534-536 ◽  
pp. 833-836 ◽  
Author(s):  
J.K. Lee ◽  
Taek Soo Kim ◽  
Ha Guk Jeong ◽  
Jung Chan Bae
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Spark Plasma Sintering ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Solid Solution Matrix ◽  
Solution Matrix ◽  
Consolidation Temperature

The microstructure and mechanical properties of the Mg97Zn1Y2 alloy prepared by spark plasma sintering of gas atomized powders have been investigated. After consolidation, precipitates were observed to form in the α-Mg solid solution matrix of the Mg97Zn1Y2 alloy. These precipitates consisted of Mg12YZn and Mg24Y5 phases. The density of the consolidated bulk Mg-Zn-Y alloy was 1.86 g/cm3. The ultimate tensile strength and elongation were dependent on the consolidation temperature, which were in the ranges of 280 to 293 MPa and 8.5 to 20.8 %, respectively.

Fabrication of Mo-Ti3SiC2 Layered Material by Spark Plasma Sintering and its Interface Stability at 800°C

2010 ◽  
Vol 638-642 ◽  
pp. 973-978
Author(s):  
Tungwai Leo Ngai ◽  
Hui Guo Luo ◽  
Jun Jun Zheng ◽  
Chang Xu Hu ◽  
Yuan Yuan Li
Keyword(s):  
Spark Plasma Sintering ◽  
Layered Composite ◽  
Layered Material ◽  
Molar Ratio ◽  
Mixed Powder ◽  
Growing Period ◽  
Intermediate Layers ◽  
Plasma Sintering ◽  
Heat Treated ◽  
Spark Plasma

Mo-Ti3SiC2 layered material was prepared by spark plasma sintering. Mixed Ti, Si, graphite and Al powder with molar ratio of 3Ti:1Si:2C:0.2Al was put into a graphite mould and pressed with a pressure of about 0.5 MPa, then, Mo powder was put on top of the mixed powder. Experimental results showed that Mo-Ti3SiC2 layered material could be fabricated successfully by sintering the above powder mixture at 1300°C for 20 minutes under a pressure of 50 MPa in vacuum. The surface and interfaces of the layered composite were tight and clear without any observable crack. In order to study the thermal stability at elevated temperature, the fabricated Mo-Ti3SiC2 layered composite was heat treated at 800°C for 5, 10, 20 and 40 hours. After 40 hours of annealing, the intermediate layers formed between the Mo and Ti3SiC2 matrix grew thicker. The interfaces are clean and tight with no obvious formation of voids and new phases. The initial 10 hours of annealing is the fast growing period, after that, the growth rate slowed down significantly.

Solid solution synthesis of tantalum carbide-hafnium carbide by spark plasma sintering

2017 ◽  
Vol 100 (5) ◽  
pp. 1853-1862 ◽  
Author(s):  
Cheng Zhang ◽  
Ankur Gupta ◽  
Sudipta Seal ◽  
Benjamin Boesl ◽  
Arvind Agarwal
Keyword(s):  
Solid Solution ◽  
Spark Plasma Sintering ◽  
Tantalum Carbide ◽  
Hafnium Carbide ◽  
Solution Synthesis ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Structural transformations of a gas-atomized Al62.5Cu25Fe12.5 alloy during detonation spraying, spark plasma sintering and hot pressing

2021 ◽  
Vol 53 (3) ◽  
pp. 379-386
Author(s):  
Igor Batraev ◽  
Witor Wolf ◽  
Boris Bokhonov ◽  
Arina Ukhina ◽  
Ivanna Kuchumova ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Hot Pressing ◽  
Single Phase ◽  
Complex Structure ◽  
Icosahedral Phase ◽  
Structural Transformations ◽  
Detonation Spraying ◽  
Complete Melting ◽  
Plasma Sintering ◽  
Spark Plasma

In this work, we traced structural transformations of an Al62.5Cu25Fe12.5 alloy, in which a quasicrystalline icosahedral phase (i-phase) can be formed, upon spraying onto a substrate and consolidation from the powder into the bulk state. The Al62.5Cu25Fe12.5 powder was obtained by gas atomization and consisted of i-phase and ?-phase AlCu(Fe). The powder was detonation sprayed (DS) and consolidated by spark plasma sintering (SPS)/hot pressing (HP). During DS, the particles experienced partial or complete melting and rapid solidification, which resulted in the formation of coatings of a complex structure. The composite regions containing i-phase were inherited from the powder alloy. The fraction of the material that experienced melting solidified as ?-phase AlFe(Cu) in the coating. It was suggested that the difficulty of obtaining i-phase upon post-spray annealing is related to aluminum depletion of the alloy during DS. During SPS and HP, the elemental composition of the alloy was preserved, while the exposure to an elevated temperature led to phase homogenization. SPS and HP conducted at 700?C resulted in full densification and the formation of a single-phase quasicrystalline alloy. The sintered single-phase alloy showed a higher microhardness in comparison with the DS coatings.

scholarly journals Легирование термоэлектрических материалов на основе твeрдых растворов SiGe в процессе их синтеза методом электроимпульсного плазменного спекания

2019 ◽  
Vol 53 (9) ◽  
pp. 1182
Author(s):  
М.В. Дорохин ◽  
П.Б. Демина ◽  
И.В. Ерофеева ◽  
А.В. Здоровейщев ◽  
Ю.М. Кузнецов ◽  
...  
Keyword(s):  
Solid Solution ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Sintering Process ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Sb Doping ◽  
Spark Plasma ◽  
Large Clusters

AbstractThe results of investigation of thermoelectric materials fabricated by spark plasma sintering and based on Si_1 –_ x Ge_ x solid solutions doped with Sb to a concentration of 0–5 at % are presented. It was found that, at Sb concentration below 1 at %, efficient doping of the solid solution was carried out during the sintering process, which allowed us to form a thermoelectric material with a relatively high thermoelectric figure of merit. An increase in the concentration of antimony in the range of 1–5 at % led to a change in the mechanism of doping, which resulted in an increase in the resistance of materials and the segregation of Sb into large clusters. For such materials, a significant decrease in the Seebeck coefficient and thermoelectric figure of merit was noted. The highest obtained thermoelectric figure of merit (ZT) with Sb doping was 0.32 at 350°C, which is comparable with known analogues for the Ge_ x Si_1 –_ x solid solution.

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