Defect and stress relaxation in HVPE-GaN films using high temperature reactively sputtered AlN buffer

2001 ◽  
Vol 230 (3-4) ◽  
pp. 381-386 ◽  
Author(s):  
T. Paskova ◽  
E. Valcheva ◽  
J. Birch ◽  
S. Tungasmita ◽  
P.-O.Å. Persson ◽  
...  
Keyword(s):  
High Temperature ◽  
Stress Relaxation ◽  
Aln Buffer

Effect of high‐temperature AlN buffer on anisotropy of semi‐polar (11‐22) GaN with two pressure growth stages

2019 ◽  
Vol 14 (9) ◽  
pp. 972-975
Author(s):  
Jun Han ◽  
Fengfeng Shi ◽  
Yanhui Xing ◽  
Peiyuan Wan ◽  
Zhiyuan Gao ◽  
...  
Keyword(s):  
High Temperature ◽  
Growth Stages ◽  
Aln Buffer

WIELAND-K88

Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Relaxation ◽  
Copper Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Relaxation Resistance ◽  
Temperature Performance ◽  
Very High

Abstract Wieland K-88 is a copper alloy with very high electrical and thermal conductivity, good strength, and excellent stress relaxation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-738. Producer or source: Wieland Metals Inc.

STRESS RELAXATION BEHAVIOUR AND MECHANISM OF HEAT TREATED INCONEL 718 IN HIGH TEMPERATURE ENVIRONMENTS

2013 ◽  
Vol 21 (1) ◽  
pp. 43-51
Author(s):  
O. Bapokutty ◽  
◽  
Z. Sajuri ◽  
J. Syarif ◽  
◽  
...  
Keyword(s):  
High Temperature ◽  
Stress Relaxation ◽  
Inconel 718 ◽  
Relaxation Behaviour ◽  
Heat Treated

Growth and characterization of GaN films on Si(111) substrate using high-temperature AlN buffer layer

2005 ◽  
Vol 198 (1-3) ◽  
pp. 350-353 ◽  
Author(s):  
Xianfeng Ni ◽  
Liping Zhu ◽  
Zhizhen Ye ◽  
Zhe Zhao ◽  
Haiping Tang ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Aln Buffer

Reloading Stress Relaxation Behavior Analysis Based on a Creep Model for High Temperature Bolting Steel

2013 ◽  
Vol 328 ◽  
pp. 950-954
Author(s):  
Wei Wei Zhang ◽  
Hong Xu ◽  
Hong Yuan Li
Keyword(s):  
High Temperature ◽  
Stress Relaxation ◽  
Steady State Creep ◽  
Relaxation Behavior ◽  
Creep Model ◽  
National Research Institute ◽  
Time Intervals ◽  
Stress Relaxation Behavior ◽  
Proposed Model ◽  
Good Agreement

An analytical method based on a creep model is being developed to investigate the effect of retightening on stress relaxation behavior for high-temperature turbine and valve studs/bolts. In order to validate the approach, the calculated results are compared to the results of uniaxial reloading stress relaxation testing, which were performed by the National Research Institute for Metals of Japan (NRIM) for 12Cr-1Mo-1W-1/4V stainless steel bolting material at 550°C. It was shown that the proposed model based on Altenbach-Gorash-Naumenko creep model for the primary and steady state creep could be applied for the present data. The calculated residual stresses versus time curves were in good agreement with the measured for initial stress level of 273.6MPa at 550°C and for specific reloading time intervals of 24, 72, 240, and 720 hours.

Elevated-Temperature Life Assessment

2021 ◽  
pp. 146-166
Author(s):  
Arun Sreeranganathan ◽  
Douglas L. Marriott
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Stress Relaxation ◽  
Damage Mechanics ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Life Assessment ◽  
Remaining Life ◽  
High Temperature Components ◽  
Remaining Life Assessment

Abstract This article provides some new developments in elevated-temperature and life assessments. It is aimed at providing an overview of the damage mechanisms of concern, with a focus on creep, and the methodologies for design and in-service assessment of components operating at elevated temperatures. The article describes the stages of the creep curve, discusses processes involved in the extrapolation of creep data, and summarizes notable creep constitutive models and continuum damage mechanics models. It demonstrates the effects of stress relaxation and redistribution on the remaining life and discusses the Monkman-Grant relationship and multiaxiality. The article further provides information on high-temperature metallurgical changes and high-temperature hydrogen attack and the steps involved in the remaining-life prediction of high-temperature components. It presents case studies on heater tube creep testing and remaining-life assessment, and pressure vessel time-dependent stress analysis showing the effect of stress relaxation at hot spots.

Long Term Stability Evaluation of Stress Improvement Effect on Ni-Based Alloy Welds by Various Residual Stress Improvement Methods

2021 ◽  
Vol 1016 ◽  
pp. 819-825
Author(s):  
Li Na Yu ◽  
Kazuyoshi Saida ◽  
Masahito Mochizuki ◽  
Kazutoshi Nishimoto ◽  
Naoki Chigusa
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Stress Relaxation ◽  
Compressive Residual Stress ◽  
Alloy 600 ◽  
Pressurized Water ◽  
Residual Stress Relaxation ◽  
Temperature Environment ◽  
Water Reactors ◽  
High Temperature Environment

Stress corrosion cracking (SCC) is one of serious aging degradation problems for the Alloy 600 components of pressurized water reactors (PWRs). In order to prevent SCC, various methods such as water jet peening (WJP), laser peening (LP), surface polishing have been used to introduce compressive stresses at the surfaces of the PWR components. However, it has been reported that such compressive residual stress introduced by these methods might be relaxed during the practical operation, because of high temperature environment. In this study, the hardness reduction behavior of the Alloy 600 processed by LP, Buff and WJP in the thermal aging process has been investigated to estimate the stability of the residual stress improving effect by each method, based on the fact that there is a correlation between the compressive residual stress relaxation and the decrease of hardness. The behavior of the residual stress relaxation in the processed materials in the high temperature environment has been discussed with kinetic analysis.

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