The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform

B. M. Hillberry - One of the best experts on this subject based on the ideXlab platform.

  • Load history effects on fatigue Crack Growth Threshold for Ti–6Al–4V and Ti-17 titanium alloys
    International Journal of Fatigue, 2001
    Co-Authors: M. A. Moshier, Theodore Nicholas, B. M. Hillberry
    Abstract:

    Abstract Load history effects on room temperature fatigue-Crack-Growth Threshold measurement are evaluated for titanium alloys Ti–6Al–4V and Ti-17. Baseline Thresholds are determined by the use of a conventional load-shedding technique. Load history is synthesized by preCracking at Δ K levels with K max greater than the subsequently measured Threshold. Threshold for the latter is defined as the first notice of Crack propagation under increasing Δ K , constant R , step loading. An empirical overload model is developed to account for preCracking history on the Threshold. Stress relief annealing after preCracking and prior to Threshold measurement is demonstrated to eliminate load history effects on rising Δ K , constant R , step loading Threshold measurement, and to be comparable to that made using load shedding, but with considerable time saving.

  • load history effects on fatigue Crack Growth Threshold for ti 6al 4v and ti 17 titanium alloys
    International Journal of Fatigue, 2001
    Co-Authors: M. A. Moshier, Theodore Nicholas, B. M. Hillberry
    Abstract:

    Abstract Load history effects on room temperature fatigue-Crack-Growth Threshold measurement are evaluated for titanium alloys Ti–6Al–4V and Ti-17. Baseline Thresholds are determined by the use of a conventional load-shedding technique. Load history is synthesized by preCracking at Δ K levels with K max greater than the subsequently measured Threshold. Threshold for the latter is defined as the first notice of Crack propagation under increasing Δ K , constant R , step loading. An empirical overload model is developed to account for preCracking history on the Threshold. Stress relief annealing after preCracking and prior to Threshold measurement is demonstrated to eliminate load history effects on rising Δ K , constant R , step loading Threshold measurement, and to be comparable to that made using load shedding, but with considerable time saving.

J. A. Hawk - One of the best experts on this subject based on the ideXlab platform.

  • Effect of 730 °C Supercritical Fluid Exposure on the Fatigue Threshold of Ni-Based Superalloy Haynes 282
    Journal of Materials Engineering and Performance, 2019
    Co-Authors: K. A. Rozman, G. R. Holcomb, C. S. Carney, Ö. N. Doğan, J. J. Kruzic, J. A. Hawk
    Abstract:

    Driven by the need to reduce CO_2 emissions from fossil power generation, new turbine working fluids are being investigated. One such fluid, supercritical carbon dioxide (sCO_2), offers potential for improved energy conversion efficiency. In situ corrosion studies on precipitate-hardened nickel superalloys in sCO_2 have shown potentially dangerous subsurface depletion of gamma prime phase. In the present work, the ex situ effect of supercritical fluid exposure on fatigue Crack Growth Thresholds was measured for the Ni-based superalloy Haynes 282. After exposure of 500 h at 730 °C, there was a small measurable and repeatable reduction in fatigue Thresholds at room temperature from 13 to 11 MPa√m after exposure. This reduction in fatigue Crack Growth Threshold occurred irrespective of the exposure environment and was attributed to a decrease in roughness-induced Crack closure.

  • Effect of 730 °C Supercritical Fluid Exposure on the Fatigue Threshold of Ni-Based Superalloy Haynes 282
    Journal of Materials Engineering and Performance, 2019
    Co-Authors: K. A. Rozman, G. R. Holcomb, Ö. N. Doğan, J. J. Kruzic, Casey Carney, J. A. Hawk
    Abstract:

    Driven by the need to reduce CO2 emissions from fossil power generation, new turbine working fluids are being investigated. One such fluid, supercritical carbon dioxide (sCO2), offers potential for improved energy conversion efficiency. In situ corrosion studies on precipitate-hardened nickel superalloys in sCO2 have shown potentially dangerous subsurface depletion of gamma prime phase. In the present work, the ex situ effect of supercritical fluid exposure on fatigue Crack Growth Thresholds was measured for the Ni-based superalloy Haynes 282. After exposure of 500 h at 730 °C, there was a small measurable and repeatable reduction in fatigue Thresholds at room temperature from 13 to 11 MPa√m after exposure. This reduction in fatigue Crack Growth Threshold occurred irrespective of the exposure environment and was attributed to a decrease in roughness-induced Crack closure.

M. A. Moshier - One of the best experts on this subject based on the ideXlab platform.

  • A technique to measure fatigue Crack Growth Threshold
    Experimental Mechanics, 2002
    Co-Authors: K. E. Goecke, M. A. Moshier
    Abstract:

    An experimental technique for determining fatigue Crack Growth Threshold is presented. This experimental technique uses an increasing Δ K step loading procedure to determine Threshold going from a no-Growth to Growth status. Stress relief annealing of the Ti-6AI-4V test specimens eliminates load history effects normally associated with the preCrack, providing a measurement equivalent to what is achieved by a standard ASTM load shed test. In addition to measuring load history free Thresholds, this increasing Δ K technique can be used to investigate different load history effects on Threshold by using the Threshold step measurement with different preCrack histories and without the subsequent annealing process. Verification of the Threshold step measurement is demonstrated by comparing measurements with standard ATSM load shed testing results.

  • Load history effects on fatigue Crack Growth Threshold for Ti–6Al–4V and Ti-17 titanium alloys
    International Journal of Fatigue, 2001
    Co-Authors: M. A. Moshier, Theodore Nicholas, B. M. Hillberry
    Abstract:

    Abstract Load history effects on room temperature fatigue-Crack-Growth Threshold measurement are evaluated for titanium alloys Ti–6Al–4V and Ti-17. Baseline Thresholds are determined by the use of a conventional load-shedding technique. Load history is synthesized by preCracking at Δ K levels with K max greater than the subsequently measured Threshold. Threshold for the latter is defined as the first notice of Crack propagation under increasing Δ K , constant R , step loading. An empirical overload model is developed to account for preCracking history on the Threshold. Stress relief annealing after preCracking and prior to Threshold measurement is demonstrated to eliminate load history effects on rising Δ K , constant R , step loading Threshold measurement, and to be comparable to that made using load shedding, but with considerable time saving.

  • load history effects on fatigue Crack Growth Threshold for ti 6al 4v and ti 17 titanium alloys
    International Journal of Fatigue, 2001
    Co-Authors: M. A. Moshier, Theodore Nicholas, B. M. Hillberry
    Abstract:

    Abstract Load history effects on room temperature fatigue-Crack-Growth Threshold measurement are evaluated for titanium alloys Ti–6Al–4V and Ti-17. Baseline Thresholds are determined by the use of a conventional load-shedding technique. Load history is synthesized by preCracking at Δ K levels with K max greater than the subsequently measured Threshold. Threshold for the latter is defined as the first notice of Crack propagation under increasing Δ K , constant R , step loading. An empirical overload model is developed to account for preCracking history on the Threshold. Stress relief annealing after preCracking and prior to Threshold measurement is demonstrated to eliminate load history effects on rising Δ K , constant R , step loading Threshold measurement, and to be comparable to that made using load shedding, but with considerable time saving.

K. A. Rozman - One of the best experts on this subject based on the ideXlab platform.

  • Effect of 730 °C Supercritical Fluid Exposure on the Fatigue Threshold of Ni-Based Superalloy Haynes 282
    Journal of Materials Engineering and Performance, 2019
    Co-Authors: K. A. Rozman, G. R. Holcomb, C. S. Carney, Ö. N. Doğan, J. J. Kruzic, J. A. Hawk
    Abstract:

    Driven by the need to reduce CO_2 emissions from fossil power generation, new turbine working fluids are being investigated. One such fluid, supercritical carbon dioxide (sCO_2), offers potential for improved energy conversion efficiency. In situ corrosion studies on precipitate-hardened nickel superalloys in sCO_2 have shown potentially dangerous subsurface depletion of gamma prime phase. In the present work, the ex situ effect of supercritical fluid exposure on fatigue Crack Growth Thresholds was measured for the Ni-based superalloy Haynes 282. After exposure of 500 h at 730 °C, there was a small measurable and repeatable reduction in fatigue Thresholds at room temperature from 13 to 11 MPa√m after exposure. This reduction in fatigue Crack Growth Threshold occurred irrespective of the exposure environment and was attributed to a decrease in roughness-induced Crack closure.

  • Effect of 730 °C Supercritical Fluid Exposure on the Fatigue Threshold of Ni-Based Superalloy Haynes 282
    Journal of Materials Engineering and Performance, 2019
    Co-Authors: K. A. Rozman, G. R. Holcomb, Ö. N. Doğan, J. J. Kruzic, Casey Carney, J. A. Hawk
    Abstract:

    Driven by the need to reduce CO2 emissions from fossil power generation, new turbine working fluids are being investigated. One such fluid, supercritical carbon dioxide (sCO2), offers potential for improved energy conversion efficiency. In situ corrosion studies on precipitate-hardened nickel superalloys in sCO2 have shown potentially dangerous subsurface depletion of gamma prime phase. In the present work, the ex situ effect of supercritical fluid exposure on fatigue Crack Growth Thresholds was measured for the Ni-based superalloy Haynes 282. After exposure of 500 h at 730 °C, there was a small measurable and repeatable reduction in fatigue Thresholds at room temperature from 13 to 11 MPa√m after exposure. This reduction in fatigue Crack Growth Threshold occurred irrespective of the exposure environment and was attributed to a decrease in roughness-induced Crack closure.

Theodore Nicholas - One of the best experts on this subject based on the ideXlab platform.

  • Load history effects on fatigue Crack Growth Threshold for Ti–6Al–4V and Ti-17 titanium alloys
    International Journal of Fatigue, 2001
    Co-Authors: M. A. Moshier, Theodore Nicholas, B. M. Hillberry
    Abstract:

    Abstract Load history effects on room temperature fatigue-Crack-Growth Threshold measurement are evaluated for titanium alloys Ti–6Al–4V and Ti-17. Baseline Thresholds are determined by the use of a conventional load-shedding technique. Load history is synthesized by preCracking at Δ K levels with K max greater than the subsequently measured Threshold. Threshold for the latter is defined as the first notice of Crack propagation under increasing Δ K , constant R , step loading. An empirical overload model is developed to account for preCracking history on the Threshold. Stress relief annealing after preCracking and prior to Threshold measurement is demonstrated to eliminate load history effects on rising Δ K , constant R , step loading Threshold measurement, and to be comparable to that made using load shedding, but with considerable time saving.

  • load history effects on fatigue Crack Growth Threshold for ti 6al 4v and ti 17 titanium alloys
    International Journal of Fatigue, 2001
    Co-Authors: M. A. Moshier, Theodore Nicholas, B. M. Hillberry
    Abstract:

    Abstract Load history effects on room temperature fatigue-Crack-Growth Threshold measurement are evaluated for titanium alloys Ti–6Al–4V and Ti-17. Baseline Thresholds are determined by the use of a conventional load-shedding technique. Load history is synthesized by preCracking at Δ K levels with K max greater than the subsequently measured Threshold. Threshold for the latter is defined as the first notice of Crack propagation under increasing Δ K , constant R , step loading. An empirical overload model is developed to account for preCracking history on the Threshold. Stress relief annealing after preCracking and prior to Threshold measurement is demonstrated to eliminate load history effects on rising Δ K , constant R , step loading Threshold measurement, and to be comparable to that made using load shedding, but with considerable time saving.