Influence of chemical compositions and creep test conditions on UK R5 creep ductility parameter lambda of W-Mo-balanced 9Cr steel

2020 ◽  
Vol 37 (5) ◽  
pp. 309-320
Author(s):  
Fujio Abe
Keyword(s):  
Creep Test ◽  
Chemical Compositions ◽  
Creep Ductility ◽  
9Cr Steel ◽  
Test Conditions

Finite Element Damage Simulations for Creep Crack Growth of SS316H With Different Geometries

2011 ◽  
Author(s):  
Chang-Sik Oh ◽  
Nak-Hyun Kim ◽  
Han-Sang Lee ◽  
Yun-Jae Kim
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Crack Growth ◽  
Creep Test ◽  
Damage Model ◽  
Creep Crack Growth ◽  
Test Results ◽  
Creep Ductility ◽  
Creep Crack ◽  
Crack Growth Rates

In this paper, creep crack growth simulations were performed based on finite element (FE) damage simulations for several types of test specimens such as C(T), CS(T), SEN(T), M(T) and SEN(B). The Graham-Walles creep law was adopted to describe all three phases of creep. The Creep parameters were obtained from uni-axial creep test results of SS316H at 550°C. Damage model was also included based on creep ductility exhaustion concept, which is defined as the ratio of creep strain to the multi-axial creep ductility. Creep crack growth rates resulting from FE simulations were compared with the experimental data.

Optimizing the sensitivity of the small-disc creep test to damage and test conditions

2007 ◽  
Vol 42 (5) ◽  
pp. 389-409 ◽  
Author(s):  
M Evans ◽  
D Wang
Keyword(s):  
Creep Test ◽  
Experimental Studies ◽  
Test Results ◽  
Optimum Conditions ◽  
Failure Times ◽  
Test Conditions ◽  
Wide Range ◽  
Small Disc ◽  
Promising Solution

The small-creep disc test is seen as a promising solution to the problem of sampling from in-service components for remanent life estimation. However, experimental studies have revealed substantial scatter in failure times resulting from variations in test and apparatus geometries. These studies therefore suggest that there exists a set of conditions that both minimizes the scatter and also maximizes the sensitivity of the disc test to the determination of remanent life, so enabling reliable estimates of the remaining life to be made. The objective of this paper is to identify such an optimum. The large scatter present in small-disc test data would make the identification of this optimum problematic and inconclusive using an experimental approach. Instead this paper uses a numerical model of the disc test to predict failure times over a wide range of test conditions. The resulting response surface is then approximated using a polynomial and from this model the optimum set of test conditions is identified. Full verification of the model (and the optimum) can then be more successfully accomplished by carrying out experiments close to the optimum conditions where scatter is the smallest. The model was shown to be capable of predicting actual experimental creep test results. Using this approach, failure times were found to be most sensitive to disc thickness and hole diameter but least sensitive to disc diameter. Under clamping, the optimum test geometry was insensitive to the applied load but sensitive to the level of damage. Without clamping, the optimum geometry was insensitive to both of these. The paper gives optimum conditions for various levels of damage under both conditions.

EFFECT OF BORON ON CREEP DUCTILITY AND CREEP RUPTURE LIFE IN 9CR-1.5MO STEEL

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2490-2495 ◽  
Author(s):  
BUMJOON KIM ◽  
JIWOO IM ◽  
MOON K. KIM ◽  
JONGHOON LEE ◽  
BYEONGSOO LIM
Keyword(s):  
Creep Test ◽  
Rupture Life ◽  
General Concept ◽  
Creep Rupture ◽  
Displacement Rate ◽  
Boron Addition ◽  
Creep Ductility ◽  
Small Punch ◽  
Uniaxial Creep ◽  
The Relationship

In this study, the relationship between the creep ductility and rupture life of 9 Cr -1.5 Mo steel with boron addition at 600°C was investigated by small punch (SP) creep test from the viewpoint of the modified Monkman-Grant relation. The amount of boron addition ranged from 0.0076wt% to 0.0196 wt%. The general concept of Monkman-Grant ductility for uniaxial creep was introduced and then particularly modified for the SP creep. The microstructure of the steel was observed to analyze the effect of boron addition on the creep ductility and rupture life. Based on the modified Monkman-Grant ductility for SP creep, it was found that the boron addition improved the creep ductility and rupture life of the 9 Cr -1.5 Mo steel. Also, the relationship between the minimum creep displacement rate and the amount of boron addition was analyzed.

OS0707 Creep Damage Evaluation of Super 9Cr Steel by Internal Pressure Creep Test with Thick Specimen

2008 ◽  
Vol 2008 (0) ◽  
pp. _OS0707-1_-_OS0707-2_
Author(s):  
Shigetada HONGOU ◽  
Hiroshige ITO ◽  
Kazuhiro Saito ◽  
Shoichi FUKAMATU
Keyword(s):  
Internal Pressure ◽  
Creep Test ◽  
Creep Damage ◽  
Damage Evaluation ◽  
Thick Specimen ◽  
9Cr Steel

Microstructural Evaluation of the Zirconia Plasma Sprayed Coating on Ti-6Al-4V Alloy after Creep Test

2008 ◽  
Vol 591-593 ◽  
pp. 839-844
Author(s):  
Danieli A.P. Reis ◽  
Cosme Roberto Moreira Silva ◽  
Claudinei dos Santos ◽  
Carlos de Moura Neto ◽  
M.J.R. Barboza ◽  
...  
Keyword(s):  
Creep Test ◽  
Constant Load ◽  
Stabilized Zirconia ◽  
Creep Tests ◽  
Test Conditions ◽  
Microstructural Evaluation ◽  
Main Factors ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Internal Level

The titanium affinity by oxygen is one of main factors that limit the application of their alloys as structural materials at high temperatures. The objective of this work was evaluating the microstructure of the of the zirconia plasma sprayed coating Ti-6Al-4V alloy in creep test. Yttria (8 wt.%) stabilized zirconia (YSZ) (Metco 204B-NS) with a CoNiCrAlY bond coat (AMDRY 995C) was atmospherically plasma sprayed on Ti-6Al-4V substrates by Sulzer Metco. Constant load creep tests were conducted with Ti-6Al-4V alloy in air and in nitrogen atmospheres in uncoated samples and in air in coated samples at stress level of 56 MPa at 700°C. The microstructural analyze show that the predominant mechanism in the test conditions was characterized by formation and coalescence of micro cavities with shape and size varieties. The cavities are corrugated in discontinue regions, like inclusions and points involving dislocation. The size and shape of dimples are governed by number and distribution of nucleated micro cavities and by stress internal level present in the material.

Thermomechanical Ageing of Copper-Clad Aluminum Wires Submitted to Creep Test Conditions

2014 ◽  
Vol 922 ◽  
pp. 207-212
Author(s):  
Antoine Gueydan ◽  
Eric Hug ◽  
Bernadette Domengès
Keyword(s):  
Heat Treatment ◽  
Applied Stress ◽  
Creep Test ◽  
Automotive Industry ◽  
Creep Tests ◽  
Test Conditions ◽  
Operating Load ◽  
Initial Heat ◽  
Initial Heat Treatment

Creep tests were performed on copper-clad aluminum wires at 423 K and different stresses to cover potential operating load ranges in automotive industry. The lifetime of the wires is strongly dependent on the existence of an initial heat treatment and on the applied stress. It can be correlated with the formation of the three intermetallics Al2Cu, AlCu and Al4Cu9 identified by TEM diffraction. All results are discussed to understand mechanisms that could lead to the embrittlement of copper-clad aluminum wires by creep.

Analytical Electron Microscopy of Ion-Implanted Metals

1985 ◽  
Vol 43 ◽  
pp. 282-285
Author(s):  
D.I. Potter ◽  
M. Ahmed ◽  
K. Ruffing
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Friction And Wear ◽  
Analytical Electron Microscopy ◽  
Chemical Compositions ◽  
Surface Chemical ◽  
Near Surface ◽  
The Past ◽  
Analytical Electron ◽  
Property Changes

Ion implantation, used extensively for the past decade in fabricating semiconductor devices, now provides a unique means for altering the near-surface chemical compositions and microstructures of metals. These alterations often significantly improve physical properties that depend on the surface of the material; for example, catalysis, corrosion, oxidation, hardness, friction and wear. Frequently the mechanisms causing these beneficial alterations and property changes remain obscure and much of the current research in the area of ion implantation metallurgy is aimed at identifying such mechanisms. Investigators thus confront two immediate questions: To what extent is the chemical composition changed by implantation? What is the resulting microstructure? These two questions can be investigated very fruitfully with analytical electron microscopy (AEM), as described below.

TEM/AEM characterization of fine-grained clay minerals in very-low-grade rocks: Evaluation of contamination by empa involving celadonite family minerals

1996 ◽  
Vol 54 ◽  
pp. 694-695
Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi
Keyword(s):  
Electron Microscopy ◽  
Volcanic Rocks ◽  
Analytical Electron Microscopy ◽  
Metamorphic Rocks ◽  
New Mineral ◽  
Chemical Compositions ◽  
Low Grade ◽  
Fine Grained ◽  
Depth Analysis ◽  
Mineral Aggregates

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.

Effects of Fundamental Frequency Contours on Sentence Recognition in Mandarin-Speaking Children With Cochlear Implants

2020 ◽  
Vol 63 (11) ◽  
pp. 3855-3864
Author(s):  
Wanting Huang ◽  
Lena L. N. Wong ◽  
Fei Chen ◽  
Haihong Liu ◽  
Wei Liang
Keyword(s):  
Cochlear Implants ◽  
Fundamental Frequency ◽  
Signal To Noise Ratio ◽  
Lexical Tone ◽  
Signal To Noise ◽  
Sentence Recognition ◽  
Test Conditions ◽  
Age Appropriate ◽  
F0 Contour ◽  
Appropriate Sentences

Purpose Fundamental frequency (F0) is the primary acoustic cue for lexical tone perception in tonal languages but is processed in a limited way in cochlear implant (CI) systems. The aim of this study was to evaluate the importance of F0 contours in sentence recognition in Mandarin-speaking children with CIs and find out whether it is similar to/different from that in age-matched normal-hearing (NH) peers. Method Age-appropriate sentences, with F0 contours manipulated to be either natural or flattened, were randomly presented to preschool children with CIs and their age-matched peers with NH under three test conditions: in quiet, in white noise, and with competing sentences at 0 dB signal-to-noise ratio. Results The neutralization of F0 contours resulted in a significant reduction in sentence recognition. While this was seen only in noise conditions among NH children, it was observed throughout all test conditions among children with CIs. Moreover, the F0 contour-induced accuracy reduction ratios (i.e., the reduction in sentence recognition resulting from the neutralization of F0 contours compared to the normal F0 condition) were significantly greater in children with CIs than in NH children in all test conditions. Conclusions F0 contours play a major role in sentence recognition in both quiet and noise among pediatric implantees, and the contribution of the F0 contour is even more salient than that in age-matched NH children. These results also suggest that there may be differences between children with CIs and NH children in how F0 contours are processed.

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