Hot pressing of hard alloys with self-propagating high temperature synthesis

1996 ◽  
Vol 51 (6) ◽  
pp. 50
Keyword(s):  
High Temperature ◽  
Hot Pressing ◽  
Hard Alloys ◽  
Temperature Synthesis ◽  
High Temperature Synthesis

scholarly journals Production of Mo2NiB2 Based Hard Alloys by Self-Propagating High-Temperature Synthesis

2019 ◽  
Vol 38 (2019) ◽  
pp. 683-691 ◽  
Author(s):  
Sevinch Rahimi Moghaddam ◽  
Bora Derin ◽  
Onuralp Yucel ◽  
M. Seref Sonmez ◽  
Meltem Sezen ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Cost ◽  
Absorption Spectrometry ◽  
Hard Alloys ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Modeling Software ◽  
Cast Alloys ◽  
Series Of Experiments

AbstractMo-Ni-B-Al as-cast alloys containing 35.5-58.7 wt% Mo, 23.0-57.6 wt% Ni, 3.3-5.2 wt% B, and 2.2-13.5 wt% Al were synthesized by Self-Propagating High-Temperature Synthesis (SHS) using a mixture of MoO3, NiO, B2O3 and Al powders in order to obtain low-cost Mo2 NiB2 containing hard materials. The first series of experiments were performed using 1.05 times the stoichiometric amount of Al. In the second series of experiments, FactSage thermochemical modeling software was used to minimize Al increasing the Mo2NiB2 formation in the as-cast alloys. The products were characterized by using atomic absorption spectrometry (AAS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-hardness techniques.

Thermodynamic Evaluation for the Synthesis of T2 Phase from Elemental Powders via In Situ Reactively Hot-Pressing

2012 ◽  
Vol 538-541 ◽  
pp. 2082-2085
Author(s):  
Lai Qi Zhang ◽  
Lei Huang ◽  
Yong Ming Hou ◽  
Jun Pin Lin
Keyword(s):  
High Temperature ◽  
Hot Pressing ◽  
Initial Temperature ◽  
Adiabatic Temperature ◽  
Advanced Technology ◽  
Thermodynamic Evaluation ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Different Temperatures

T2 phase(Mo5SiB2) is a key component of the two Mo-Si-B tri-phase alloys under hot research. However, there is little research on T2 phase, especially its mechanic characteristics, due to the difficulty of fabrication of pure T2. In this present work, the thermodynamics of an advanced technology to fabricate pure T2 phase i.e. IRHP (In-situ Reactively Hot-Pressing) using elemental powders was analyzed. Formation free enthalpies at different temperatures for the compounds in Mo-Si-B system were calculated. Adiabatic temperatures and molten fractions of T2 phase at different initial temperatures for the reaction of synthesizing T2 phase were evaluated. The results show that it is feasible to in-situ synthesize T2 phase from elemental powders. T2 phase can not be synthesized using SHS(Self-propagating High-temperature Synthesis) mode of combustion. On the contrary, the explosion mode of combustion (IRHP) is receivable. Adiabatic temperature and molten fraction of T2 phase are relevant to initial temperature.

PECULIARITIES OF THE SYNTHESIS OF HIGH-TEMPERATURE CERAMICS TASI2–SIC, REINFORCED IN SITU BY DISCRETE SILICON CARBIDE NANOFIBERS

2018 ◽  
pp. 72-76
Author(s):  
S. Vorotilo ◽  
E. D. Polozova ◽  
E. A. Levashov
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
High Temperature ◽  
Relative Density ◽  
Hot Pressing ◽  
Temperature Synthesis ◽  
Similar Composition ◽  
High Temperature Synthesis ◽  
Sic Ceramic

The possibility of the increase of the properties of ceramics in the TaSi2–SiC system via the reinforcement by the SiC nanofibers formed in situ in the combustion wave has been studied. For the formation of nanofibers as well as for increase of the exothermicity of the reaction mixtures, energetic additive PTFE (C2F4) was used. Using the method of self-propagating high-temperature synthesis of the mechanically activated mixtures, 70%TaSi2+30%SiC ceramic was produced, with SiC present as the round-shaped grains and as nanofibers. Ceramic specimens sintered by hot pressing were characterized by relative density up to 98 %, hardness 19,0–19,2 GPa and fracture toughness 7,5–7,8 MPa·m1/2, which is noticeably above the fracture toughness of the ceramic with similar composition produced without the PTFE additions.

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