scholarly journals Relationship of Mechanical Characteristics and Microstructural Features to the Time-Dependent Edge-Notch Sensitivity of Inconel 718 Sheet

1973 ◽  
Vol 95 (2) ◽  
pp. 112-123 ◽  
Author(s):  
D. J. Wilson
Keyword(s):  
Inconel 718 ◽  
Mechanical Characteristics ◽  
Rupture Life ◽  
Dislocation Motion ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Motion Mechanism ◽  
Notched Specimens ◽  
Edge Notch ◽  
Relationship Of

Time-dependent notch sensitivity of Inconel 718 sheet was observed at 900 deg F to 1200 deg F (482–649 deg C). It occurred when edge-notched specimens were loaded below the yield strength and smooth specimen tests showed that small amounts of creep consumed large rupture life fractions. The severity of the notch sensitivity was reduced by decreasing the temperature of the solution treatments, increasing the time and/or temperature of aging and increasing the test temperature to 1400 deg F (760 deg C). Elimination of time-dependent notch sensitivity correlated with a change in dislocation motion mechanism from shearing to bypassing precipitate particles.

Notch Sensitivity, Mechanical, and Microstructural Characteristics of TD-NiCr at Elevated Temperatures

1974 ◽  
Vol 96 (2) ◽  
pp. 109-114 ◽  
Author(s):  
D. J. Wilson ◽  
A. Ferrari
Keyword(s):  
Inconel 718 ◽  
Mechanical Characteristics ◽  
Elevated Temperatures ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Microstructural Characteristics ◽  
Notched Specimen ◽  
Theoretical Concepts ◽  
Notched Specimens ◽  
Good Agreement

Tensile and creep-rupture tests were conducted for smooth and sharp edge-notched specimens of 0.015-in. (0.38 mm) thick TD-NiCr sheet at 1000 to 1800 deg F (538–982 deg C). The dislocation mechanisms operative were in good agreement with theoretical concepts. Time-dependent notch sensitivity was not observed. The notched specimen behavior correlated with the same mechanical characteristics and microstructural features as previously established for Waspaloy and Inconel 718 which are strengthened by coherent precipitates.

The Dependence of the Notch Sensitivity of Waspaloy at 1000–1400 Deg F on the Gamma Prime Phase

1973 ◽  
Vol 95 (1) ◽  
pp. 15-20 ◽  
Author(s):  
D. J. Wilson
Keyword(s):  
Mechanical Behavior ◽  
Dislocation Motion ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Motion Mechanism ◽  
Gamma Prime ◽  
Edge Notch ◽  
Prime Phase

The morphology of the gamma prime phase was correlated with the mechanical behavior of Waspaloy sheet at 1000–1400 deg F. “Overaging” eliminated time-dependent edge-notch sensitivity and produced a change in the dislocation motion mechanism from shearing to bypassing the gamma prime particles.

Sensitivity of the Creep-Rupture Properties of Waspaloy Sheet to Sharp-Edged Notches in the Temperature Range 1000–1400 Deg F

1972 ◽  
Vol 94 (1) ◽  
pp. 13-21 ◽  
Author(s):  
D. J. Wilson
Keyword(s):  
Necessary Conditions ◽  
Rupture Life ◽  
Creep Rupture ◽  
Optimum Combination ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Notched Specimen ◽  
Solution Treated ◽  
Material Solution ◽  
Rupture Properties

Time-dependent notch sensitivity of Waspaloy was observed at test temperatures from 1000 to 1300 deg F. Its occurrence in this range was dependent on the heat treatment. “Overaging” eliminated the notch sensitivity. Optimum combination of smooth and notched specimen strengths for material solution treated at 1975 deg F were obtained by aging 24 hr at 1550 deg F. Necessary conditions for time-dependent notch sensitivity were (i) the notch specimen loads had to be below the approximate 0.2 percent off set yield strength; and (ii) test data from smooth specimens had to indicate that small amounts of creep used up large fractions of creep-rupture life. No reasons were evident why these criteria will not prove applicable to other alloys.

scholarly journals Deformation Characteristics and Time-Dependent Notch Sensitivity of Udimet 700 at Intermediate Temperatures

1975 ◽  
Vol 97 (3) ◽  
pp. 223-233 ◽  
Author(s):  
D. J. Wilson
Keyword(s):  
Particle Size ◽  
Yield Strength ◽  
Average Particle Size ◽  
Time Dependent ◽  
Notch Sensitivity ◽  
Average Particle ◽  
Deformation Characteristics ◽  
Notched Specimen ◽  
Notched Specimens ◽  
Sensitive Behavior

Time-dependent notch sensitivity of Udimet 700 sheet, bar, and investment castings was observed between 1000 deg and 1400 deg F (538–760 deg C) but not at 1600 deg F (871 deg C). As was the case for Modified Waspaloy, Waspaloy, Rene´ 41, INCONEL 718 and TD-NiCr, it occurred when notched specimens were loaded below the yield strength and when creep deformation was localized. For each γ′ strengthened alloy and notched specimen geometry, a stress-average particle size zone can be defined to characterize the notch sensitive behavior.

Ageing Precipitate Strengthening of Cu-Containing Structural Steels

2011 ◽  
Vol 399-401 ◽  
pp. 144-147
Author(s):  
Hai Yan Wang ◽  
Hui Ping Ren ◽  
Zong Chang Liu
Keyword(s):  
High Purity ◽  
Metastable Phase ◽  
Ferrite Matrix ◽  
Dislocation Motion ◽  
Microstructure Observation ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Relationship Of ◽  
Precipitate Strengthening ◽  
Observation Results

Microstructure evolution of Fe-1.18%Cu high purity steels during solution and aging was investigated under high-resolution electron microscope (HREM). In addition, the aging strengthening mechanisms were discussed based on the microstructure observation. The results show that there were lots of Cu atom clusters in ferrite matrix during solid solution and aging initial stages, subsequently, Cu-rich metastable Fe-Cu particles precipitate at the aging strength peak. It is found that the intense strengthening is controlled by the coherency relationship of Fe-Cu metastable phase with matrix that forms the obstacle of the dislocation motion, while the decrease of strength after the peak is attributed to the loss of coherency, which should highly likely be the dominant reason of aging strengthening in Cu bearing high purity steels Thus our TEM observation results are in reasonably agreement with some previous assume.

Stress Rupture Behavior of Disk Superalloys Exposed to Low-Temperature Hot Corrosion Environment

2020 ◽  
Author(s):  
Dipankar Dua ◽  
Mohammad Khajavi ◽  
Gary White ◽  
Deepak Thirumurthy ◽  
Jaskirat Singh
Keyword(s):  
Low Temperature ◽  
Hot Corrosion ◽  
Inconel 718 ◽  
Gas Turbines ◽  
Rupture Life ◽  
Stress Rupture ◽  
Stress Rupture Life ◽  
Corrosive Environments ◽  
The Impact ◽  
Temperature Surface

Abstract Siemens Energy has a large fleet of aero-derivative gas turbines. The performance and durability of these power turbines largely depend on the capability of hot section components to resist high-temperature surface attacks and to maintain their mechanical properties. Hot corrosion attack occurs due to exposure of turbine components to sulfur-bearing fuels/air together with other corrosive compounds during turbine operation. This paper investigates the impact of low-temperature hot corrosion on the stress rupture of commonly used gas turbine disk alloys, including Inconel 718, Incoloy 901, and A-286. The results indicate that Inconel 718 and Incoloy 901 maintain their creep strength advantage over A-286 in a low-temperature hot corrosion inducing environment at 1100°F. All three materials exhibited an equivalent life reduction in the corrosive environments at 1100°F. Moreover, the results demonstrate that the stress-rupture life of materials in hot-corrosion environments depends on the combined and cumulative effects of corrosion-resistant and hardening elements.

Creep–rupture model of aluminum alloys: Cohesive zone approach

2014 ◽  
Vol 229 (8) ◽  
pp. 1343-1347 ◽  
Author(s):  
Kyungmok Kim
Keyword(s):  
Aluminum Alloys ◽  
Cohesive Zone ◽  
Rupture Life ◽  
Stress Rupture ◽  
Creep Rupture ◽  
Time Dependent ◽  
Element Analysis ◽  
Rupture Model ◽  
Term Creep

In this article, a creep–rupture model of aluminum alloys is developed using a time-dependent cohesive zone law. For long-term creep rupture, a time jump strategy is used in a cohesive zone law. Stress–rupture scatter of aluminum alloy 4032-T6 is fitted with a power law form. Then, change in the slope of a stress-rupture line is identified on a log–log scale. Implicit finite element analysis is employed with a model containing a cohesive zone. Stress–rupture curves at various given temperatures are calculated and compared with experimental ones. Results show that a proposed method allows predicting creep–rupture life of aluminum alloys.

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