The Mechanisms Analysis of the ACF Bonding Strengths after the High Temperature/ Humidity Environment Test

2007 ◽  
Vol 353-358 ◽  
pp. 2875-2878
Author(s):  
Jun Zhang ◽  
Xu Chen ◽  
Xin Li Wei ◽  
Yong Cheng Lin
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
Bonding Strength ◽  
Interfacial Stresses ◽  
Humidity Condition ◽  
Humidity Environment

The environmental experiments of the thermal cycling (-40~125°C) and the high temperature/humidity (85°C, 85%RH) aging were used to evaluate the reliability of the specimens bonded with ACFs. It was found that the high temperature/humidity was the harshest condition to the ACFs bonding. The DSC testing and interfacial stresses analysis has been done under the high temperature/humidity condition. The mechanisms of the bonding strength decrease were investigated.

High Temperature Bonding Effect of the Room-Temperature-Curing Phosphate Adhesive for C/C Composites

2016 ◽  
Vol 680 ◽  
pp. 179-183 ◽  
Author(s):  
Ming Chao Wang ◽  
Meng Meng Zhuang ◽  
Xin Tao ◽  
Xi Qing Xu ◽  
Hai Tao Geng ◽  
...  
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Thermal Cycling ◽  
Bonding Strength ◽  
Room Temperature ◽  
Temperature Range ◽  
Heat Resistant ◽  
Bonding Effect ◽  
Temperature Shear

A heat-resistant phosphate adhesive was developed for joining and repairing of C/C composites. The high-temperature bonding effect for both cured adhesive and 1300°C-calcined adhesive had been evaluated through testing high-temperature shear strength of corresponding joints. The results showed that the bonding strength of cured adhesive decreased from 7.9 MPa at RT to 0.9 MPa at 1300°C, while that of 1300°C-calcined adhesive could maintain about 4 MPa at temperature range from RT to 700°C and then decreased to 1.7 MPa at 1300°C. Besides, with the increasing thermal cycling times at 1300°C, the high-temperature bonding strength at this temperature could maintain at about 2.3 MPa.

KUBOTA ALLOY KHR12C

Alloy Digest ◽  
1999 ◽  
Vol 48 (3) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Thermal Cycling ◽  
Tensile Properties ◽  
Casting Alloy ◽  
Type Ii ◽  
Temperature Performance

Abstract Kubota alloy KHR12C is an austenitic Fe-Cr-Ni-Nb casting alloy developed from the well known HH type II grade. This alloy is superior to other grades in components that are subjected to frequent thermal cycling and shock. The alloy is available in both centrifugal and static castings. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: SS-738. Producer or source: Kubota Metal Corporation.

scholarly journals Insight into the Mechanical Performance of the UHPC Repaired Cementitious Composite System after Exposure to High Temperatures

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4095
Author(s):  
Qing Chen ◽  
Zhiyuan Zhu ◽  
Rui Ma ◽  
Zhengwu Jiang ◽  
Yao Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
High Temperatures ◽  
Bonding Strength ◽  
Composite System ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Interfacial Structure ◽  
Cementitious Composite ◽  
Average Percentage

In this paper, the mechanical performance of an ultra-high-performance concrete (UHPC) repaired cementitious composite system, including the old matrix and the new reinforcement (UHPC), under various high temperature levels (20 °C, 100 °C, 300 °C, and 500 °C) was studied. In this system, UHPC reinforced with different contents of steel fibers and polypropylene (PP) fibers was utilized. Moreover, the physical, compressive, bonding, and flexural behaviors of the UHPC repaired system after being exposed to different high temperatures were investigated. Meanwhile, X-ray diffraction (XRD), baseline evaluation test (BET), and scanning electron microscope (SEM) tests were conducted to analyze the effect of high temperature on the microstructural changes in a UHPC repaired cementitious composite system. Results indicate that the appearance of the bonded system changed, and its mass decreased slightly. The average percentage of residual mass of the system was 99.5%, 96%, and 94–95% at 100 °C, 300 °C, and 500 °C, respectively. The residual compressive strength, bonding strength, and flexural performance improved first and then deteriorated with the increase of temperature. When the temperature reached 500 °C, the compressive strength, bonding strength, and flexural strength decreased by about 20%, 30%, and 15% for the UHPC bonded system, respectively. Under high temperature, the original components of UHPC decreased and the pore structure deteriorated. The cumulative pore volume at 500 °C could reach more than three times that at room temperature (about 20 °C). The bonding showed obvious deterioration, and the interfacial structure became looser after exposure to high temperature.

Experimental Research on Bond Strength between Rebar and Concrete after High Temperature

2011 ◽  
Vol 71-78 ◽  
pp. 1057-1061 ◽  
Author(s):  
Ke Fang Yin ◽  
Yang Han ◽  
Yi Liu
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Bond Strength ◽  
Experimental Research ◽  
Bonding Strength ◽  
Different Temperatures ◽  
Ultimate Bond Strength

With the centrally pulling-out test, the bond strength of reinforced concrete is measured with different temperatures and different cooling ways after high temperature; and the ultimate bond strength and slip of reinforced and concrete under different conditions are analyzed. The results show that the bonding strength declines gradually with the increase of temperature, and the ultimate slippage also decreases gradually.

scholarly journals High temperature x-ray diffraction of zr-2.5nb during thermal cycling in vacuum

2017 ◽  
Vol 110 ◽  
pp. 01084 ◽  
Author(s):  
Mikhail Tumanov ◽  
Lyudmila Lyubimova ◽  
Evgeniy Puzyrev
Keyword(s):  
High Temperature ◽  
Thermal Cycling ◽  
X Ray Diffraction ◽  
X Ray

Cyclone Maintenance Improvement via Special Refractory Anchor Pin Studs

2004 ◽  
Author(s):  
Stephen R. Swartz
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Thermal Cycling ◽  
Thermal Spray ◽  
Effective Means ◽  
Protective Layer ◽  
Spray Coating ◽  
Cycle Performance ◽  
Alloy 625 ◽  
430 Stainless Steel

Since the inception of the cyclone style boiler, industry has become accustomed to performing routine maintenance during every scheduled shutdown occurring 12 months to 18 months between cycles. These maintenance cycles are influenced by service factor, loading and the type design. The same problems exist in both the standard and super critical cyclones; severe deterioration of refractory and the anchoring pin studs. This paper focuses on one type of refractory failure mechanism caused by the anchoring pin studs. Most operators have found that the most effective means of applying refractory in this type situation is to “ram” the refractory in and around the anchoring pin studs thus creating a dense lining with maximum integrity. Coupled with proper application of anchoring pin studs and a special designed coating, typical volumetric expansion of the pin studs from corrosion attack and oxidation is eliminated thus extending the life of the refractory. This mechanism is discussed along with the results of the coating performance as it relates to extreme heat oxidation and thermal cycling in laboratory tests. A protective coating was developed using a nano-cored thermal spray wire technology that produces a uniform, adherent protective layer against high temperature corrosion and oxidation. The coating yields similar thermal conductivity as a bare stud thus experiencing excellent thermal cycle performance. This specially designed thermal spray coating is applied to standard 430 stainless steel pin studs thus providing the necessary barrier against aggressive high temperature environments while maintaining excellent heat conductivity. The coating has a high amount of tungsten (40+%) in a nickel matrix with greatly reduced oxides at the substrate and throughout the coating. With these attributes for the anchoring pin studs in mind, a newly designed stud was evaluated in heat oxidation tests up to 2000°F and thermal cycling test and compared to 430 stainless steel, chromized and Alloy 625. The new stud out-performed all others even in the as-welded condition. Further corrosion testing in ferric chloride (ASTM G48) showed them to be superior to Alloy 72 and Alloy 625 in the thermal spray and welded condition. Proper welding equipment and welding techniques are also discussed since weld continuity impacts overall performance of anchoring pin studs with refractory linings. A major test site will be examined in the spring of 2004 for it’s full effectiveness in service and will be documented in order that all data retrieved would be available to the entire industry.

Study on Bonding Properties of Copper and Aluminum in Nano Scale Using Molecular Dynamics Simulation

2012 ◽  
Vol 152-154 ◽  
pp. 183-187 ◽  
Author(s):  
Quang Cherng Hsu ◽  
Yen Yu Cheng ◽  
Bao Hsin Liu
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Bonding Strength ◽  
High Speed ◽  
Tensile Force ◽  
Pure Aluminum ◽  
Pure Copper ◽  
Dynamics Simulation ◽  
Low Speed ◽  
Speed Condition

According to MD simulation results, pressing depth between two bonding materials will affect bonding strength. Alloy material (Al0.9Cu0.1) had void defect phenomenon in low bonding speed condition because the increasing chance of atom migration which will result in low bonding strength. High tensile speed causes material fracture phenomena happen earlier than low speed. Material stress in low speed is smaller than in high speed. Fracture morphology of material is different in different tensile speed. In low speed condition, material can be stretched thinner than in high speed condition. Material in high temperature has greater kinetic energy than low temperature; therefore, material in high temperature has better formability and behaves larger tensile strain than low temperature. For pure aluminum, when temperature raises to 900K which is close to melting point (933K), its crystal structure is no longer belongs to F.C.C. structure, so bonding strength is weaker than low temperature. Large size material has larger contact area than small size material; therefore, the tensile force and tensile strength of the former are larger than the latter. The order of bonding strength for these three materials is: binary alloy > pure copper > pure aluminum.

Study on Thermal Cycling of Sn0.7Cu Solder

2013 ◽  
Vol 791-793 ◽  
pp. 362-365
Author(s):  
Li Yang ◽  
Ju Li Li ◽  
Jing Guo Ge ◽  
Meng Li ◽  
Nan Ji
Keyword(s):  
Shear Stress ◽  
Steady State ◽  
High Temperature ◽  
Thermal Cycling ◽  
Shear Strain ◽  
Maximum Shear Stress ◽  
Steady State Creep ◽  
Maximum Shear Strain ◽  
Cycle Number ◽  
State Cycle

Thermal cycling of a unit Sn0.7Cu solder was studied based on the steady-state creep constitutive equation and Matlab software. The results show that there is a steady-state cycle for the thermal cycling of unit Sn0.7Cu eutectic solder. In steady-state thermal cycling, the shear stress is increased with the increase of temperature. There is a stage of stress relaxation during high temperature. A liner relationship between maximum shear stress and maximum shear strain is observed during thermal cycling. The metastable cycle number is declined greatly with the increase of maximum shear strain.

scholarly journals LC/8YSZ TBCs Thermal Cycling Life and Failure Mechanism under Extreme Temperature Gradients

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1051
Author(s):  
Kun Liu ◽  
Xi Chen ◽  
Kangping Du ◽  
Yu Wang ◽  
Jinguang Du ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Temperature ◽  
Thermal Cycling ◽  
Thermal Shock ◽  
Failure Mechanism ◽  
Extreme Temperature ◽  
Temperature Gradients ◽  
Accelerated Life Test ◽  
Ceramic Layer ◽  
Cycling Life

The purpose of this paper is to study the thermal shock resistance and failure mechanism of La2Ce2O7/8YSZ double-ceramic-layer thermal barrier coatings (LC/8YSZ DCL TBCs) under extreme temperature gradients. At high surface temperatures, thermal shock and infrared temperature measuring modules were used to determine the thermal cycling life and insulation temperature of LC/8YSZ DCL TBCs under extreme temperature gradients by an oxygen–acetylene gas flame testing machine. A viscoelastic model was used to obtain the stress and strain law of solid phase sintering of a coating system using the finite element method. Results and Conclusion: (1) Thermal cycling life was affected by the surface temperature of LC/8YSZ DCL TBCs and decreased sharply with the increase of surface temperature. (2) The LC ceramic surface of the failure coating was sintered, and the higher the temperature, the faster the sintering process. (3) Accelerated life test results showed that high temperature thermal cycling life is not only related to thermal fatigue of ceramic layer, but is also related to the sintering degree of the coating. (4) Although the high temperature thermal stress had great influence on the coating, great sintering stress was produced with sintering of the LC ceramic layer, which is the main cause of LC/8YSZ DCL TBC failure. The above results indicate that for new TBC ceramic materials, especially those for engines above class F, their sinterability should be fully considered. Sintering affects the thermal shock properties at high temperature. Our research results can provide reference for material selection and high temperature performance research.

Sign in / Sign up

Export Citation Format

Share Document