scholarly journals Effect of Initial Powders on Properties of FeAlSi Intermetallics

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2846 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Václav Bouček ◽  
Kateřina Nová ◽  
...  

FeAlSi intermetallics are materials with promising high-temperature mechanical properties and oxidation resistance. Nevertheless, their production by standard metallurgical processes is complicated. In this study, preparation of powders by mechanical alloying and properties of the samples compacted by spark plasma sintering was studied. Various initial feedstock materials were mixed to prepare the material with the same chemical composition. Time of mechanical alloying leading to complete homogenization of powders was estimated based on the microstructure observations, results of XRD and indentation tests. Microstructure, phase composition, hardness and fracture toughness of sintered samples was studied and compared with the properties of powders before the sintering process. It was found that independently of initial feedstock powder, the resulting phase composition was the same (Fe3Si + FeSi). The combination of hard initial powders required the longest milling time, but it led to the highest values of fracture toughness.

2015 ◽  
Vol 655 ◽  
pp. 22-26
Author(s):  
Xiao Fei Shi ◽  
Zhi Xin Cai ◽  
Chao He ◽  
Jian Jun Wang ◽  
Xin Yan Yue ◽  
...  

cBN/SiAlON composites were prepared by spark plasma sintering (SPS) method using Si3N4, AlN, Al2O3,cBN and Y2O3 powders as raw materials. The sintering process is at the temperature of 1500°C holding for 5 min. Effect of the Y2O3 content on phase composition, microstructure, bulk density, hardness and fracture toughness of the cBN/SiAlON composite was investigated. The experimental results showed that when the Y2O3 content was 0.2 wt. % the bulk density and fracture toughness of the composite had the maximum values of 3.0 g/cm3 and KIC = 5.7 MPa∙m1/2, respectively. The cBN/SiAlON composite with 0.8 wt. % Y2O3 addition got the maximum hardness of 16.4 GPa.


2018 ◽  
Vol 875 ◽  
pp. 41-46 ◽  
Author(s):  
Yue Ying Li ◽  
Fu Wen Zhu ◽  
Zhen Liang Qiao

TiB2 particulate reinforced titanium matrix composites were prepared by mechanical alloying and spark plasma sintering. Volume fraction of TiB2 powders in the composites are 5%, 10%, 15%. The effect of milling time and the volume fraction of reinforcement on microstructure and properties of the composites were studied. The results show that with increasing milling time, the size of powder particles decreases, quantity of them increases, and microstructure of the sintered samples becomes finer and more uniform. When milling time reaches 30h, the trend of powder agglomeration increases, the downward trend of the particle size becomes slowly. With the milling time, the density of titanium matrix composites is on the rise. The density of 10vol%TiB2 particulate reinforced titanium matrix composites can reach 4.799 g/cm3, with 30h milling time and sintering at 900°C. The density and hardness of the composites increase with increasing the volume fraction of TiB2. When the volume fraction of TiB2 is 15%, after milling 10h and sintered at 800°C, the density and hardness of the composites can reach 4.713g/cm3 and HV851.58.


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5221
Author(s):  
Jaroslaw Wozniak ◽  
Mateusz Petrus ◽  
Tomasz Cygan ◽  
Artur Lachowski ◽  
Bogusława Adamczyk-Cieślak ◽  
...  

This paper discusses the influence of Ti3C2 (MXene) addition on silicon nitride and its impact on the microstructure and mechanical properties of the latter. Composites were prepared through powder processing and sintered using the spark plasma sintering (SPS) technic. Relative density, hardness and fracture toughness, were analyzed. The highest fracture toughness at 5.3 MPa·m1/2 and the highest hardness at HV5 2217 were achieved for 0.7 and 2 wt.% Ti3C2, respectively. Moreover, the formation of the Si2N2O phase was observed as a result of both the MXene addition and the preservation of the α-Si3N4→β-Si3N4 phase transformation during the sintering process.


2006 ◽  
Vol 6 (11) ◽  
pp. 3429-3432
Author(s):  
Chung-Hyo Lee ◽  
Seong-Hee Lee ◽  
Sung-Yong Chun ◽  
Sang-Jin Lee

A mixture of pure Mg and Si powders with an atomic ratio 2:1 has been subjected to mechanical alloying (MA) at room temperature to prepare the Mg2Si thermoelectric material. Mg2Si intermetallic compound with a grain size of 50 nm can be obtained by MA of Mg66.7Si33.3 powders for 60 hours and subsequently annealed at 620 °C. Consolidation of the MA powders was performed in a spark plasma sintering (SPS) machine using graphite dies up to 800–900 °C under 50 MPa. The shrinkage of consolidated samples during SPS was significant at about 250 °C and 620 °C. X-ray diffraction data shows that the SPS compact from 60 h MA powders consolidated up to 800 °C consists of only nanocrystalline Mg2Si compound with a grain size of 100 nm.


2021 ◽  
Vol 21 (3) ◽  
Author(s):  
M. Petrus ◽  
J. Woźniak ◽  
T. Cygan ◽  
A. Lachowski ◽  
A. Rozmysłowska-Wojciechowska ◽  
...  

AbstractThis article describes the manufacturing of silicon carbide composites with the addition of quasi-two-dimensional titanium carbide Ti3C2, known as MXene. The composites were obtained by the powder metallurgy technique, consolidated with the use of the Spark Plasma Sintering method at 1900 °C and dwelled for 30 min. The influence of the Ti3C2 MXene addition on the microstructure and mechanical properties of the composites was investigated. The structure of the MXene phase after the sintering process was also analyzed. The results showed a significant increase (almost 50%) of fracture toughness for composites with the addition of 0.2 wt% Ti3C2 MXene. In turn, the highest hardness, 23.2 GPa, was noted for the composite with the addition of the 1.5 wt% Ti3C2 MXene phase. This was an increase of over 10% in comparison to the reference sample. The analysis of chemical composition and observations using a transmission electron microscope showed that the Ti3C2 MXene phase oxidizes during sintering, resulting in the formation of crystalline, highly defected, disordered graphite structures. The presence of these structures in the microstructure, similarly to graphene, significantly affects the hardness and fracture toughness of silicon carbide.


2019 ◽  
Vol 822 ◽  
pp. 617-627 ◽  
Author(s):  
I.S. Goncharov ◽  
Nikolay G. Razumov ◽  
Aleksey I. Shamshurin ◽  
Qing Sheng Wang

Synthesis of the Nb-Si in-situ composite was attempted by mechanical alloying of element powders in vario-planetary ball mill. The particles size distribution was measured by laser diffraction, microstructures were examined with scanning electronic microscope, and the phase constituent were analyzed by X-ray diffraction. The amorphization of the Si during mechanical alloying, large amount of deformation of Nb crystal structure, and after all – the formation of supersaturated solid solution of Nb was observed. To stabilize microstructure and phase composition, a spark plasma sintering was attempted. After SPS microstructure consist of three main phases – Nbss, Nb5Si3 and Nb3Si.


2007 ◽  
Vol 534-536 ◽  
pp. 893-896 ◽  
Author(s):  
Swapan Kumar Sarkar ◽  
Min Ho Youn ◽  
Ik Hyun Oh ◽  
Byong Taek Lee

Carbon nanotube (CNT) reinforced hydroxyapatite (HAp) composites were fabricated by using the spark plasma sintering process with surfactant modified CNT and HAp nano powder. Without the dependency on sintering temperature, the main crystal phase existed with the HAp phase although a few contents of β-TCP (Tri calcium phosphate) phase were detected. The maximum fracture toughness, (1.27 MPa.m1/2) was obtained in the sample sintered at 1100 oC and on the fracture surface a typical intergranular fracture mode, as well as the pull-out pmhenomenon of CNT, was observed.


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