Friction stress measurements during creep of Nimonic 105

Burt, H.; Dennison, J.P.; Wilshire, B.

doi:10.1179/msc.1979.13.5.295

Cited by 63 publications

(12 citation statements)

References 8 publications

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“…Such extended tertiary creep has been observed in many engineering materials, such as Ni-based superalloys [25,26] and low alloy ferritic steels. [27,28] Contrary to conventional tertiary creep that arises from the loss of section by either external damage such as necking or internal damage in the form of creep cavitation, extended tertiary creep is usually associated with microstructural degradation.…”

Section: A Extended Tertiary Creepmentioning

confidence: 98%

Creep and rupture properties of a squeeze-cast Mg-Al-Ca alloy

Zhu

Mordike

Nie

2006

Metall Mater Trans A

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A squeeze-cast Mg-Al-Ca alloy (MRI153) was creep tested at 150, 175, and 200 °C under applied stresses in the range of 30 to 120 MPa. The creep curves were characterized by an extended tertiary stage in which the creep rate increases progressively with the creep strain. Microstructural examinations revealed the precipitation and coarsening of new particles during creep. The stress dependence of the minimum creep rate suggests a transition from power-law creep at low stresses to power-law breakdown at high stresses. Creep rupture of this alloy occurred as a result of cavitation damage at dendritic grain boundaries, with the creep rupture time and the minimum creep rate following the empirical Monkman-Grant equation. A comparison is made between the creep and rupture properties of MRI153 and those of a squeeze-cast Mg-Al alloy (AZ91).

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Section: A Extended Tertiary Creepmentioning

confidence: 98%

Creep and rupture properties of a squeeze-cast Mg-Al-Ca alloy

Zhu

Mordike

Nie

2006

Metall Mater Trans A

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“…(19), we obtain the same equation with eq. (15). This means that the power law equation is theoretically significant only when n ¼ 1.…”

Section: Back Ground Of the Exponential Law And Power Lawmentioning

confidence: 99%

“…2,6) However, as pointed by Feltham and Meakin 14) and/or Rösler and Artz, 15) the physical meanings of the stress exponents, n and n 0 , and the apparent activation energies, Q and Q 0 , have not yet been clear. Moreover, though the some metallurgical explanations 16,17) were made concerning with the internal stresses, in general, the internal stress has not yet been correlated with microstructural parameters quantitatively.…”

Section: Introductionmentioning

confidence: 99%

Applicability of an Exponential Law in Creep of Metals

2003

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An exponential type creep equation has been developed for heat resistant steels by the authors. This equation was induced assuming both a thermally activated process for a mobile dislocation and rather high applied stress. The applicability of the new creep equation was examined for a pure iron, two kinds of Ni-base super alloys and an eutectic solder alloy in a Pb-Sn system which were tested at relatively high temperatures and under very low stresses. All of the data obtained were completely explained by the new creep equation. The data for each alloy were classified into a few groups, where a deformation mechanism may be different with each other. The new creep equation is valid for stresses higher than the half value of the slope in a logarithm of time to rupture vs. linear stress diagram.

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“…Further, unrealistically high values of stress exponents (much higher than n¼5) are generally observed for creep behavior of precipitation and dispersion strengthened alloys [17][18][19]22,[32][33][34][35][36][37][38][39][40]. This has been overcome by rationalizing the steady-state creep rate in terms of an effective stress which is the difference between the applied stress and the resisting stress [22,[32][33][34][35][36][37][38][39][40]. The resisting stress is a measure of resistance to dislocation motion caused by other dislocations and by strengthening precipitates/particles as in the case of precipitation/dispersion strengthened alloys.…”

Section: Determination Of Resisting Stressmentioning

confidence: 99%

“…In the method proposed by Lagneborg and Bergman [22] and subsequently followed by other researchers [17][18][19] for determining resisting stress, it is assumed that the mechanism changes from climb by-pass over particles at lower stresses to Orowan bowing or particle shearing at higher stresses causing the threshold stress. The concept of resisting stress pioneered by Threadgill and Wilshire [32] has been widely used to rationalize the creep behavior of precipitation hardened alloys [32][33][34][35][36][37], dispersion strengthened alloys [38][39][40], Cr-Mo ferritic steels [17,19], Ni-Al hardened austenitic stainless steel [18] and composite materials [41,42].…”

Section: Determination Of Resisting Stressmentioning

confidence: 99%