Hardening mechanisms in a dynamic strain aging alloy, HASTELLOY X, during isothermal and thermomechanical cyclic deformation

Miner, R. V.; Castelli, Michael G.

doi:10.1007/bf02801173

Cited by 62 publications

(31 citation statements)

References 11 publications

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“…Solute atmospheres form on the forest dislocations and then drain by pipe diffusion from the forest dislocations to the mobile dislocations. In the study of the HASTELLOY* X superalloy by Miner and Castelli, [36] a considerable increase in dislocation density was observed in the operating-temperature range of the DSA process, compared with that at room temperature. Thus, when the DSA process operates, additional dislocations are generated in order to maintain the imposed strain.…”

Section: A Dsa Precipitation Of Carbides and Nitrides And Their Inmentioning

confidence: 97%

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The low-cycle fatigue and fatigue-crack-growth behavior of HAYNES® HR-120 alloy

Chen

Liaw

McDaniels

et al. 2003

Metall Mater Trans A

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The low-cycle fatigue and fatigue-crack-growth behavior of the HAYNES HR-120 alloy was investigated over the temperature range of 24°C to 980°C in laboratory air. The result showed that increasing the temperature usually led to a substantial decrease in the low-cycle fatigue life. The reduction of fatigue life could be attributed to oxidation and dynamic strain-aging (DSA) processes. The strain vs fatigue-life data obtained at different temperatures were analyzed. It was also found that the fatigue-crack-growth rate per cycle generally increased with increasing temperature and R ratio (R ϭ min / max , where min and max are the applied minimum and maximum stresses, respectively). The relationship between the stress-intensity-factor range and fatigue-crack-growth rate was determined. Scanning-electron-microscopy (SEM) examinations of the fracture surfaces revealed that the fatigue cracks initiated and propagated predominantly in a transgranular mode.

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Section: A Dsa Precipitation Of Carbides and Nitrides And Their Inmentioning

confidence: 97%

“…This inverse temperature dependence has been frequently cited as the main evidence for the occurrence of DSA. [35,36] Moreover, it was noted that the variation of the plasticstrain range with temperature exhibited an abnormal behavior. The plastic-strain range at half-life as a function of temperature …”

Section: Materials and Experimental Proceduresmentioning

confidence: 98%

The low-cycle fatigue and fatigue-crack-growth behavior of HAYNES® HR-120 alloy

Chen

Liaw

McDaniels

et al. 2003

Metall Mater Trans A

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“…This may suggest that the TMF macroscopic behavior is most influenced by the substructural features associated with the peak temperature, as was found with the nickel base superalloy, Hastelloy X [11,16].…”

Section: Isothermally Developed Deformation Substructuresmentioning

confidence: 72%

Cyclic Deformation of Haynes 188 Superalloy Under Isothermal and Thermomechanical Loadings

Castelli¹,

Rao²

1996

Superalloys 1996 (Eighth International Symposium)

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A detailed assessment of the macroscopic and microstructural cyclic deformation behavior of Haynes 188" has been conducted under various isothermal and thermomechanical conditions over the temperature range 26 to 1000°C.A fully reversed mechanical strain range of 0.8% was examined with constant mechanical strain rates of 109s-' and 104s-'. Particular attention was given to the effects of dynamic strain aging (DSA) on the stress-strain response. Detailed transmission electron microscopy was conducted to examine the deformation substructures and establish correlations with the cyclic macroscopic behaviors. Although DSA was found to occur over a wide temperature range between approximately 300 and 700°C the microstructural characteristics and deformation mechanisms responsible for DSA varied considerably and were dependent upon temperature. In general, the operation of DSA processes led to a maximum of the cyclic stress amplitude at -65O"C, and was accompanied by pronounced planar slip, the generation of stacking faults and high dislocation density. DSA was evidenced through a combination of phenomena, including serrated yielding, an inverse dependence of maximum cyclic hardening with strain rate (6), and an instantaneous inverse 8 sensitivity.The TMF cyclic hardening behavior exhibited unique behaviors in comparison to the isothermal response, predominantly at the minimum TMF temperature extremes.

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“…It is indicating that many Orowan loops appear in this region. Moreover, high dislocation densities developed in the test and distributed randomly, which could produce great hardening effect [15]. Obviously, severe plastic deformation occurred in the region close to the fracture.…”

Section: Introductionmentioning

confidence: 99%