Cyclic hardening and softening behavior of a fully annealed zircaloy-4

To investigate the property of a new type of Zircaloy material, a low cycle fatigue (LCF) test has been performed at room temperature (RT) and 375°C. Results show that the new alloy generally displays cyclic hardening followed by a continuous softening behavior. Fatigue lifetime curves as a function of strain range imply that the new alloy has a nearly same lifetime than that of Zr-4 at RT, and superior than that at 375°C.

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Comparative Low-Cycle Fatigue Behavior of HAYNES 244 Alloy and Waspaloy

10.1115/gt2021-59619 ◽

2021 ◽

Author(s):

Michael G. Fahrmann

Keyword(s):

Thermal Loading ◽

Coefficient Of Thermal Expansion ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Axial Strain ◽

Fatigue Crack Initiation ◽

High Strength ◽

Cyclic Hardening ◽

Cycle Fatigue ◽

Softening Behavior

Abstract HAYNES® 244® alloy was chiefly developed to address the need for high-strength, low coefficient of thermal expansion (CTE) alloys for seal rings and cases in advanced gas turbine engines. In addition to these attributes, adequate resistance to low-cycle fatigue (LCF) due to cyclic thermal and mechanical loading during service is critical for such applications. The isothermal LCF performance of commercially produced 0.5” (12.5 mm) thick, fully heat treated plate products of 244 alloy was evaluated by means of axial strain-controlled (R = −1) LCF tests covering total strain ranges up to 1.25 % (without dwells), at temperatures ranging from 800–1400°F (427–760°C). In addition, the comparative LCF performance of Waspaloy, a well-established alloy for turbine cases, was evaluated under selected, nominally identical test conditions. S-N curves were constructed and fitted by the Coffin-Manson equation, allowing the delineation of regimes controlled by the elastic and plastic response of the material. Fracture surfaces were examined in the scanning electron microscope to identify fatigue crack initiation sites and crack propagation modes. Differences between the alloys are discussed in terms of tensile strength and cyclic hardening/softening behavior. Implications for fatigue performance of these alloys under cyclic thermal loading conditions are discussed as well.

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Cyclic hardening and softening of Alz.sbnd;2.9Cu2.2Mg0.6Mn alloyUstinovshikov, Y. J. Mater. Sci. 1 July 1992 27, (13), 3662–3666

International Journal of Fatigue ◽

10.1016/0142-1123(93)90479-a ◽

1993 ◽

Vol 15 (4) ◽

pp. 350-350

Keyword(s):

Cyclic Hardening ◽

Hardening And Softening

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Elevated Temperature Fatigue Behavior of 2 1/4 Cr-1 Mo Steel

Journal of Pressure Vessel Technology ◽

10.1115/1.3454304 ◽

1975 ◽

Vol 97 (4) ◽

pp. 252-257 ◽

Cited By ~ 6

Author(s):

C. R. Brinkman ◽

M. K. Booker ◽

J. P. Strizak ◽

W. R. Corwin

Keyword(s):

Elevated Temperature ◽

Room Temperature ◽

Fatigue Behavior ◽

Cyclic Hardening ◽

Fatigue Tests ◽

Annealed Condition ◽

Temperature Range ◽

Hardening And Softening

Results are reported for a number of load and strain controlled fatigue tests conducted over the temperature range of room temperature to 1000°F (538°C). Cyclic hardening and softening characteristics for a single heat of 2 1/4 Cr-1 Mo steel in the isothermally annealed condition are discussed. Comparisons of the data generated in this effort are made with data available from the literature and from these compilations possible ASME design fatigue curves were prepared covering continuous high and low cycle behavior over the temperature range of room temperature to 1100°F (593°C). Equations for these design curves are also given.

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