Local Mechanical Properties at the Dendrite Scale of Ni-Based Superalloys Studied by Advanced High Temperature Indentation Creep and Micropillar Compression Tests

2020 ◽  
pp. 273-281
Author(s):  
Lukas Haußmann ◽  
Steffen Neumeier ◽  
Markus Kolb ◽  
Johannes Ast ◽  
Gaurav Mohanty ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Indentation Creep ◽  
Compression Tests ◽  
Micropillar Compression

Deformation of an extruded nickel beryllide between room temperature and 820 °C

1991 ◽  
Vol 6 (12) ◽  
pp. 2653-2659 ◽  
Author(s):  
G.M. Pharr ◽  
S.V. Courington ◽  
J. Wadsworth ◽  
T.G. Nieh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Flow Stress ◽  
Strain Hardening ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Compression Tests ◽  
Tension And Compression ◽  
Better Than

The mechanical properties of nickel beryllide, NiBe, have been investigated in the temperature range 20–820 °C. The room temperature properties were studied using tension, bending, and compression tests, while the elevated temperature properties were characterized in compression only. NiBe exhibits some ductility at room temperature; the strains to failure in tension and compression are 1.3% and 13%, respectively. Fracture is controlled primarily by the cohesive strength of grain boundaries. At high temperatures, NiBe is readily deformable—strains in excess of 30% can be achieved at temperatures as low as 400 °C. Strain hardening rates are high, and the flow stress decreases monotonically with temperature. The high temperature strength of NiBe is as good or better than that of NiAl, but not quite as good as CoAl.

scholarly journals An Effect of Chromium on Mechanical Properties of the Ni3Al-Based Alloys and Sinters in Compression Tests

2011 ◽  
Vol 56 (4) ◽  
pp. 1007-1014 ◽  
Author(s):  
W. Malec ◽  
K. Rzyman ◽  
M. Czepelak ◽  
A. Wala
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Point Of View ◽  
Compression Tests ◽  
Wide Range ◽  
Cast Alloys ◽  
Intended Use ◽  
Temperature Applications

An Effect of Chromium on Mechanical Properties of the Ni3Al-Based Alloys and Sinters in Compression TestsMechanical properties of the Ni75Al(25-x)Crx cast alloys and sinters were investigated using compression tests conducted within a wide range of compositions and temperature. The alloys and sinters exhibiting the best mechanical properties from a point of view of their intended use as constructional materials suitable for high-temperature applications were selected.

scholarly journals Three-Dimensional (3D) Microstructure-Based Modeling of a Thermally-Aged Cast Duplex Stainless Steel Based on X-ray Microtomography, Nanoindentation and Micropillar Compression

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 688
Author(s):  
Qingdong Zhang ◽  
Kai Zhu ◽  
Arun Sundar S. Singaravelu ◽  
Weizhao Sun ◽  
Tao Jing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Three Dimensional ◽  
Compression Tests ◽  
Element Analysis ◽  
X Ray ◽  
3D Microstructure ◽  
Individual Phase ◽  
Micropillar Compression

Finite element analysis was conducted on a thermally-aged cast duplex stainless steel based on the true three-dimensional (3D) microstructure obtained from X-ray microtomography experiments and using the constitutive behavior of each individual phase extracted from nanoindentation on single-crystal and bicrystal micropillar compression tests. The evolution of the phase morphology, the mechanical properties and the boundary deformation behavior during the aging process are highlighted. Quantitative analysis in terms of the distribution and evolution of the stress and strain in both the as received and aged conditions was performed. The experimental results show that aging at an intermediate temperature has a negligible influence on the morphology of the two phases in cast duplex stainless steel (CDSS). Results from simulations reveal that the mechanical behavior of this material were seriously affected by the microstructure and the mechanical properties of the individual phase and the necking deformation tend to form in the area with less large ferrite grains after aging. In addition, stress localization tends to form at the austenite/ferrite interface, in the narrow region of ferrite grains and in the small ferrite grains.

High Temperature Mechanical Properties of Ti(C,N)-Co-Mo2C Cermets

2009 ◽  
Vol 423 ◽  
pp. 83-88 ◽  
Author(s):  
Angela Gallardo-López ◽  
A. Morales-Rodríguez ◽  
Arturo Domínguez-Rodríguez ◽  
J.M. Córdoba ◽  
M.A. Avilés ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Inert Atmosphere ◽  
Plastic Behavior ◽  
Compression Tests ◽  
Creep Tests ◽  
Temperature Oxidation ◽  
High Temperature Mechanical Properties ◽  
One Step ◽  
The One

The creep behavior of a TiCxN1-x-Co-Mo2C cermet has been investigated at temperatures between 1100-1200°C in an inert atmosphere to assess the one step mechanically induced self-sustaining reaction synthesis and pressureless sintering process, and the influence of the Mo2C additive in the high temperature mechanical properties of this cermet. The samples deform plastically at the chosen temperatures, and values of the stress exponent (n=1.70.6) and activation energy (Q= 4.30.5 eV) have been estimated from uniaxial compression tests. No significant grain growth has been detected after deformation. The reproducibility of the creep tests compared to other compositions indicates that the Mo2C addition contributes to increase notably the resistance to high temperature oxidation of the samples, so that the plastic behavior is not affected by oxidation when deformation experiments are performed in an inert atmosphere.

scholarly journals Tests on the Mechanical Properties of Corroded Cement Mortar after High Temperature

2020 ◽  
Vol 6 (3) ◽  
pp. 459-469 ◽  
Author(s):  
Xiong Liang-Xiao ◽  
Chen Cong
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Sodium Sulfate ◽  
Sea Water ◽  
Cement Mortar ◽  
Peak Stress ◽  
Sulfate Solution ◽  
Sodium Sulfate Solution ◽  
Compression Tests

Durability of cement mortar and concrete materials under sea water condition is always an important research topic. The objective of this work is to understand the mechanical properties of corroded cement mortar after high temperature, the cement mortar specimens after high temperature were placed in water and sodium sulfate solution, and then the uniaxial compression tests were carried out on the cement mortar specimens after corroded. Test results show that both the differences of compressive strength and strain at the peak stress after high temperature caused by high temperature, are relatively small when the specimens are eroded in water, and the differences are relatively high when the specimens are eroded in sodium sulfate solution. The compressive strength of the cement mortar specimens under normal temperature eroded in sodium sulfate solution is highest, and that eroded in water is lowest. The compressive strength of specimen after high temperature eroded in water is highest and that eroded in sodium sulfate solution is lowest. The strain at the peak stress of specimen, whether after high temperature or not, is highest when eroded in sodium sulfate solution, and that eroded in water is lowest. At present, there are few research results about the mechanical properties of concrete first after high temperature and then after sea water corrosion. The work in this paper can enrich the results in this area.

scholarly journals Experimental Study of the Effect of High Temperature on the Mechanical Properties of Coarse Sandstone

2019 ◽  
Vol 9 (12) ◽  
pp. 2424 ◽  
Author(s):  
Sijiang Wei ◽  
Yushun Yang ◽  
Chengdong Su ◽  
Syabilla Rachmadina Cardosh ◽  
Hao Wang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Rock Strength ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Temperature Threshold ◽  
Compression Tests ◽  
Fracture Angle ◽  
Different Temperatures ◽  
Actual Fracture

In order to study the effect of high temperature on the mechanical properties of rock, two groups of coarse sandstone samples were subjected to the uniaxial compression and triaxial compression test at room temperature of 25 °C and high temperatures of 100~1000 °C. The study comes to some conclusions: (1) With the increase of temperature, the longitudinal wave velocity gradually decreases, and the damage factor of temperature gradually increases. (2) For uniaxial compression tests at different temperatures, the high temperature action within 500 °C has a strengthening effect on the compression strength, and the high temperature effect has a weakening effect on the compression strength when temperatures exceed 500 °C; so 500 °C is the temperature threshold. (3) For triaxial compression tests at different temperatures, the rock strength is positively correlated with temperature and confining pressure when the temperature is lower than 800 °C and the confining pressure is lower than 15 MPa; the rock strength is negatively correlated with temperature and confining pressure when the temperature is over 800 °C and confining pressure is above 15 MPa, so 800 °C is the temperature threshold, and 15 MPa is the confining pressure threshold. (4) In the triaxial compression, the actual fracture angle of the sample after high temperature is basically the same as the theoretical calculation value, high temperature has little effect on the actual fracture angle of the sample, and the actual fracture angle is negatively correlated with the confining pressure.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

TEM Studies of Grain Boundary Films in Si3N4 Ceramics

1991 ◽  
Vol 49 ◽  
pp. 930-931
Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Hot Isostatic Pressing ◽  
Amorphous Film ◽  
Liquid Phase Sintering ◽  
Second Phase ◽  
High Temperature Mechanical Properties ◽  
Triple Points ◽  
Boundary Films

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.

AEM of reaction-bonded SiC

1992 ◽  
Vol 50 (1) ◽  
pp. 344-345
Author(s):  
K Das Chowdhury ◽  
R. W. Carpenter ◽  
W. Braue
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
High Temperature ◽  
Epitaxial Growth ◽  
Liquid Silicon ◽  
Structural Ceramic ◽  
Few Data

Research on reaction-bonded SiC (RBSiC) is aimed at developing a reliable structural ceramic with improved mechanical properties. The starting materials for RBSiC were Si,C and α-SiC powder. The formation of the complex microstructure of RBSiC involves (i) solution of carbon in liquid silicon, (ii) nucleation and epitaxial growth of secondary β-SiC on the original α-SiC grains followed by (iii) β>α-SiC phase transformation of newly formed SiC. Due to their coherent nature, epitaxial SiC/SiC interfaces are considered to be segregation-free and “strong” with respect to their effect on the mechanical properties of RBSiC. But the “weak” Si/SiC interface limits its use in high temperature situations. However, few data exist on the structure and chemistry of these interfaces. Microanalytical results obtained by parallel EELS and HREM imaging are reported here.

Sign in / Sign up

Export Citation Format

Share Document