Evaluating High Temperature Modulus and Strength of Alumina Tube in Vacuum by a Modified Split Ring Method

2016 ◽  
Vol 680 ◽  
pp. 9-12
Author(s):  
Zhao Liu ◽  
Yi Wang Bao ◽  
Chun Lin Hu ◽  
De Tian Wan ◽  
Yuan Tian
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
High Temperature ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Bending Strength ◽  
Heating Furnace ◽  
Alumina Tube ◽  
Split Ring ◽  
Ring Method

Alumina is a typical ceramic material and possesses high strengthand stiffness at both room temperature and high temperature. The split ring methodhad been established to evaluate the elastic modulus and bending strength of aluminatube materials at ambient temperature. However, both equations for modulus andstrength became lightly inapplicable with the increased temperature. For theelastic modulus, it was lack of precise approaches and advices for deformationmeasurement in the heating furnace. For the bending strength, changes of sampledimensions due to thermal expansion would take an effect on the calculatingresults. In this work, several improvements have been taken into account tocalibrate the above deviations. Results revealed that the modulus and strengthregularly decreased from room temperature to 1300 °C and accorded well with other conventional testing methods.It proved the accuracy and reliability of this modified split ring method,which might be used to evaluate other ceramic tube materials at hightemperature.

Fracture Mechanics of Y2O3 Ceramics at High Temperatures

2014 ◽  
Vol 89 ◽  
pp. 88-93
Author(s):  
Marek Boniecki ◽  
Zdzislaw Librant ◽  
Władysław Wesołowski ◽  
Magdalena Gizowska ◽  
Marcin Osuchowski ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
High Temperature ◽  
Fracture Mechanics ◽  
High Purity ◽  
Room Temperature ◽  
Bending Strength ◽  
Hot Isostatic Pressing ◽  
Temperature Changes ◽  
Four Point Bending

Fracture toughness KIc and four-point bending strength σc at high temperature (up to 1500 °C) of Y2O3 ceramics of various grain size were measured. The ceramics were prepared by pressureless air sintering and next hot isostatic pressing of high purity (99.99%) Y2O3 powder. Relative density of about 99 % was achieved. Photos of microstructures revealed small pores distributed mainly inside grains. For smallest grain size (2 - 9 μm) ceramics KIc and σc are almost constant from 20 ° to 1200 °C and next they decrease. For biggest grain size (about 44 μm) they increase up to 800 °C and next they keep constant up to 1200 °C. The micrographs analyses of fracture surfaces indicated that transgranular mode of fracture at room temperature changes to almost intergranular at higher temperatures.

Study on Elasto-Plastic Stability Bearing Capacities for K6 Single-Layer Reticulated Shells under Fire Conditions

2012 ◽  
Vol 204-208 ◽  
pp. 1174-1178 ◽  
Author(s):  
Yin Bai ◽  
Jian Lei Zhai ◽  
Yong Jiu Shi ◽  
Yuan Qing Wang
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Temperature Distribution ◽  
Ambient Temperature ◽  
Single Layer ◽  
Calculation Formula ◽  
Uniform Temperature ◽  
Global Instability ◽  
Stability Bearing Capacity ◽  
Plastic Stability

The elastic modulus of steel will decrease in case of high temperature which makes the reticulated shells easier to have the global instability phenomenon. In order to obtain the elasto-plastic stability bearing capacities for K6 single-layer reticulated shells [1], nonlinear finite analysis compete process was conducted by ANAYS software under on the two typical cases which include global non-uniform temperature distribution and localized high temperature. Based on the calculation formula for single-layer reticulated shells at ambient temperature, the calculation formula for elasto-plastic stability bearing capacity for K6 single-layer reticulated shells was obtained.

Effect of Preparation Process on Bending Modulus and Strength of Fiber Tubes in Radial Direction

2017 ◽  
Vol 726 ◽  
pp. 3-7
Author(s):  
Zhao Liu ◽  
Chun Lin Hu ◽  
Yi Wang Bao
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Radial Direction ◽  
Bending Strength ◽  
Potential Method ◽  
Preparation Process ◽  
Bending Modulus ◽  
Closed Ring ◽  
The Matrix ◽  
Ring Method

To explore the effects of preparation process on the mechanical properties of fiber reinforced tubes in radial direction, the closed ring method was applied to assess the elastic modulus and bending strength of GFRP and CFRP prepared by winding method and pultrusion method, respectively. The results indicate that there are two obvious differences between the winding tube and the pultrusion tube: i) the elastic modulus and bending strength of the winding tube for two materials are larger than that of the pultrusion tube. It should be attributed to the position of materials under stress: the former is the fibers while the latter is the matrix; ii) the failure mode for the winding tube is brittle fracture while elastic-plastic fracture is for the pultrusion tube. Compared with other experimental methods, the results of the closed ring method are accurate and reliable, which is demonstrated to be a potential method to evaluate the mechanical properties of fiber tubes in radial direction rapidly and conveniently.

Thermal expansion coefficients and Gruneisen parameters of quartz at high temperature by X-ray method

1994 ◽  
Vol 9 (2) ◽  
pp. 148-150
Author(s):  
Nabil N. Rammo ◽  
Saad B. Farid
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Ambient Temperature ◽  
Least Squares ◽  
Temperature Variation ◽  
Ray Method ◽  
X Ray ◽  
Least Squares Fitting ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The temperature variation of the interplanar spacings (101), (112), and (211) of 325 mesh quartz was determined in the range 300–966 °K using X-ray powder diffractometry. The measured lattice parameters have been found to increase nonlinearly with temperature, and the dependence has been expressed by a polynomial of second degree from the least-squares fitting of the data, the results of which are presented herein. Values are given for the thermal expansion coefficients and Gruneisen parameter in the range 300 to 768 °K. In the range 768–966 °K, the expansion is zero. The derivatives dαa/dT, dαc/dT, and dαv/dT at ambient temperature are also given.

Behaviors of the Zr–1.0Sn–0.39Nb–0.31Fe–0.05Cr Alloy at High Temperature

2011 ◽  
Vol 399-401 ◽  
pp. 80-84
Author(s):  
Yi Yuan Tang ◽  
Jie Li Meng ◽  
Kai Lian Huang ◽  
Jian Lie Liang
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
High Temperature ◽  
Oxide Film ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thin Oxide Film ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Phase transformation of the Zr-1.0Sn-0.39Nb-0.31Fe-0.05Cr alloy was investigated by high temperature X-ray diffraction (XRD). The XRD results revealed that the alloy contained two precipitates at room temperature, namely β-Nb and hexagonal Zr(Nb,Fe,Cr,)2. β-Nb was suggested to dissolve into the α-Zr matrix at the 580oC. Thin oxide film formed at the alloy’s surface was identified as mixture of the monoclinic Zr0.93O2and tetragonal ZrO2, when the temperature reached to 750oC and 850 oC. The thermal expansion coefficients of αZr in this alloy was of αa = 8.39×10-6/°C, αc = 2.48×10-6/°C.

High Temperature Thermal Expansion and Elastic Modulus of Steels Used in Mill Rolls

2011 ◽  
Vol 21 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Alexander Laptev ◽  
Bernd Baufeld ◽  
Akhilesh Kumar Swarnakar ◽  
Stanislav Zakharchuk ◽  
Omer van der Biest
Keyword(s):  
Thermal Expansion ◽  
Elastic Modulus ◽  
High Temperature

The Influence of Microstructure, Heat-Treatment and Type of Crystal Lattice of Iron Aluminides on Coefficient of Thermal Expansion

2016 ◽  
Vol 368 ◽  
pp. 41-44 ◽  
Author(s):  
Martin Švec
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Thermal Expansion ◽  
High Temperature ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Iron Aluminides ◽  
Sharp Drop ◽  
Structural Application ◽  
Phase Transition Temperatures

The iron aluminides seem to be very perspective materials for high temperature structural application. They have many advantages, but unfortunately also some negative properties – e.g. sharp drop in strength above 600°C or limited ductility at room temperature. These disadvantages can be reduced by alloying of binary alloy by other elements.Present work deals with a study of coefficient of thermal expansion (CTE). It was investigated the influence of microstructure and heat-treatment on the values of CTE. Secondary, it was studied the possibilities, how to determine phase transition temperatures from CTE curves. Influence of type of iron aluminides lattice on CTE values was also examined as well as the influence of addition of alloying elements into binary iron aluminides.

A high-temperature X-ray diffraction study of the NiO–Li2O system

1971 ◽  
Vol 4 (4) ◽  
pp. 293-297 ◽  
Author(s):  
C. J. Toussaint
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Thermal Expansion ◽  
High Temperature ◽  
Transition Temperature ◽  
Diffraction Study ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallographic Study

A crystallographic study of the system Ni2+ 1−2x Ni3+ x Li+ x O has been carried out. The crystal structure of the material in the range 0≤x≤0.4 at room temperature and up to 1000°C has been studied. The principal coefficients of thermal expansion and the phase diagram are given. The structural rhombohedral → face-centred cubic transition temperature of NiO has been determined.

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