Composite materials based on Al2O3‒SiC‒TiB2 obtained by SHS extrusion and their hightemperature annealing

2021 ◽  
pp. 51-55
Author(s):  
A. P. Chizhikov ◽  
A. S. Konstantinov ◽  
M. S. Antipov ◽  
P. M. Bazhin ◽  
A. M. Stolin
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Pressing Pressure ◽  
Technological Parameters ◽  
Temperature Synthesis ◽  
Shs Extrusion ◽  
High Temperature Synthesis ◽  
Before And After

As a result of the combination of the processes of selfpropagating high-temperature synthesis (SHS) and shear high-temperature deformation, realized in the method of SHS-extrusion, ceramic rods based on Al2O3‒SiC‒TiB2 were obtained. The influence of technological parameters of the process (delay time, pressing pressure) on the length of the obtained rods has been studied. The obtained materials were annealed in the range 1000‒1300 °C, and the microstructure and phase composition of the materials were studied before and after heat treatment.

Self-Propagating High-Temperature Synthesis, Dynamic/Quasi-Static Densification, and Superplasticity of Ceramics

2006 ◽  
Vol 45 ◽  
pp. 933-938
Author(s):  
Yury A. Gordopolov ◽  
Nail G. Zaripov ◽  
Larissa V. Gordopolova
Keyword(s):  
High Temperature ◽  
Titanium Carbide ◽  
High Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Testing System ◽  
Strain Rates ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Dynamic Densification

The microstructure evolution during high-temperature deformation at (a) high strain rates and low strains (dynamic densification, shock compression) and (b) low strain rates and high strains (quasi-static densification, superplastic regime) was studied. Off-stoichiometric titanium carbide was selected as a testing system. The results demonstrate that high-temperature deformation in a broad range of strain rates provides means for controlling the microstructure of titanium carbide. By varying deformation conditions, one can obtain materials differing in microstructure and chemical composition, in particular, with equilibrium and nonequilibrium microstructures. Accordingly, the physicochemical properties of such materials are also different.

Effect of Residual Stress on High Temperature Deformation in a Weld Stainless Steel

2006 ◽  
Vol 524-525 ◽  
pp. 311-316 ◽  
Author(s):  
Robert C. Wimpory ◽  
Farid R. Biglari ◽  
Rainer Schneider ◽  
Kamran M. Nikbin ◽  
N.P. O'Dowd
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Imperial College ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Collaborative Effort ◽  
Specific Objective ◽  
Before And After

This paper considers the measurement of residual stresses induced by mechanical loading in a weld Type 347 stainless steel. The work is based in part on an ongoing Round Robin collaborative effort by the Versailles Agreement on Materials and Standards, Technical Working Area 31, (VAMAS TWA 31) working on ‘Crack Growth of Components Containing Residual Stresses’. The specific objective of the work at Imperial College London and HMI, Berlin is to examine how residual stresses and prior straining and subsequent relaxation at high temperature contribute to creep crack initiation and growth for steels relevant to power plant applications. Tensile residual stresses have been introduced in the weld by pre-compression and neutron diffraction measurements have been carried out before and after stress relaxation at 650 oC. Significant relaxation of the residual stresses has been observed, in agreement with earlier work on a stainless steel. Preliminary results suggest that the strains local to the crack drop by over 60% after 1000 h relaxation at 650 oC for the weld steel. The results have been compared with finite element studies of elastic-plastic pre-compression and stress relaxation due to creep.

Development of Coupled Model of SHS-Extrusion

2014 ◽  
Vol 1040 ◽  
pp. 461-465
Author(s):  
I.V. Mekhanich
Keyword(s):  
Mathematical Model ◽  
High Temperature ◽  
Coupled Model ◽  
Temperature Synthesis ◽  
One Dimensional ◽  
Shs Extrusion ◽  
High Temperature Synthesis

In this paper mathematical model of self-propagating high-temperature synthesis combined with extrusion was proposed and investigated. The problem was solved in one-dimensional formulation with consideration of viscous, thermal and concentration stresses. Evolution of temperature, density was investigated.

scholarly journals Microstructure Evolution and Mechanical Properties of 0.4C-Si-Mn-Cr Steel during High Temperature Deformation

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 172 ◽  
Author(s):  
Fei Zhang ◽  
Yang Yang ◽  
Quan Shan ◽  
Zulai Li ◽  
Jinfeng Bi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Impact Toughness ◽  
Microstructure Evolution ◽  
Cast Steel ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
The Impact

Herein, the effects of height-diameter ratios (H/D) on the microstructure evolution and mechanical properties of 0.4C-Si-Mn-Cr steel during high temperature deformation are reported. The compression experiments were performed on steel samples using Gleeble to obtain a reasonable deformation temperature, and the degree of deformation was assessed in the range of 1.5 to 2.0 H/D via forging. The forged specimens were quenched using the same heat treatment process. The hardness and impact toughness of the steel samples were tested before and after heat treatment. Grain sizes gradually increased with an increase in the compression temperature from 950 °C to 1150 °C, and the grain sizes decreased with an increase in H/D. The microstructure of the steel samples contained pearlite, bainite, martensite, and retained austenite phase. The microstructure after forging was more uniform and finer as compared to that of as-cast steel samples. The hardness and impact toughness of the steel samples were evaluated after forging; hardness first increased and then decreased with an increase in H/D, while the impact toughness continuously increased with an increase in H/D. Hence, the microstructure and properties of steel could be improved via high temperature deformation, and this was primarily related to grain refinement.

scholarly journals Production of hollow ceramic rods by SHS extrusion

2019 ◽  
Vol 484 (6) ◽  
pp. 709-711
Author(s):  
А. P. Chizhikov ◽  
A. M. Stolin ◽  
P. M. Bazhin ◽  
M. I. Alymov
Keyword(s):  
High Temperature ◽  
Viscoelastic Properties ◽  
Redox Reactions ◽  
Die Swell ◽  
Mechanism Of Formation ◽  
Chromium Oxides ◽  
Temperature Synthesis ◽  
Shs Extrusion ◽  
Chromium Boride ◽  
High Temperature Synthesis

The possibility of producing hollow ceramic rods from an Al2O3-based material by SHS extrusion was first shown. A mechanism of formation of such rods by die swell was proposed. It was demonstrated that, at high temperatures, the material can have viscoelastic properties. The studies were performed in the system 2B2O3-6Al-2Cr2O3, in which a ceramic material based on aluminum and chromium oxides with strengthening chromium boride particles forms by self-propagating high temperature synthesis and redox reactions.

Precipitates as Internal Markers for High Temperature Deformation Studies

1974 ◽  
Vol 32 ◽  
pp. 494-495
Author(s):  
K. Nuttall
Keyword(s):  
High Temperature ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Diffusion Creep ◽  
Before And After ◽  
Probable Occurrence ◽  
Boundary Sliding ◽  
And Diffusion

A problem in the study of high temperature deformation mechanisms such as grain boundary sliding or diffusion creep is to obtain good metallographic evidence to demonstrate the probable occurrence of such processes. The difficulty arises because marked changes in microstructure such as those commonly observed after dislocation creep, e.g. grain elongation, sub-grain formation, changes in dislocation distribution, are not usually associated with sliding and diffusion creep so that microstructural comparisons before and after deformation are not too informative. Surface markers are frequently used as an indication of relative grain sliding and rotation, but there are separate difficulties in relating these observations to bulk behaviour.

Mechanical properties of a 20 vol % SiC whisker-reinforced, yttria-stabilized, tetragonal zirconia composite at elevated temperatures

1995 ◽  
Vol 10 (1) ◽  
pp. 113-118 ◽  
Author(s):  
S.E. Dougherty ◽  
T.G. Nieh ◽  
J. Wadsworth ◽  
Y. Akimune
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Tetragonal Zirconia ◽  
Tensile Tests ◽  
Engineering Properties ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Properties ◽  
Before And After

The high-temperature deformation behavior of a SiC whisker-reinforced, yttria-stabilized, tetragonal zirconia polycrystalline composite containing 20 vol % SiC whiskers (SiC/Y-TZP) has been investigated. Tensile tests were performed in vacuum at temperatures from 1450 °C to 1650 °C and at strain rates from 10−3 to 10−5 s−1. The material exhibits useful high-temperature engineering properties (e.g., ∼100 MPa and 16% elongation at T = 1550 °C and at a strain rate of ∼10−4 s−1). The stress exponent was determined to be n ≍ 2. Scanning electron microscopy was used to characterize the grain size and morphology of the composites, both before and after deformation. The grain size in the composite was initially fine, but coarsened at the test temperatures; both dynamic and static grain growth were observed. The morphology of ceramic reinforcements appears to affect strongly the plastic deformation properties of Y-TZP. A comparison is made between the properties of monolithic Y-TZP, 20 wt. % Al2O3 particulate-reinforced Y-TZP (Al2O3/Y-TZP), and SiC/Y-TZP composites.

Sign in / Sign up

Export Citation Format

Share Document