Hot Deformation Behavior of Superalloy 718

Garcia, Christian; Wang, G.D.; Camus, D.E.; Loria, Edward A.; DeArdo, A. J.

doi:10.7449/1994/superalloys_1994_293_302

Cited by 19 publications

(16 citation statements)

References 2 publications

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“…Garcia did the similar research works in the temperature range from 900°C to 1177"~ and strain rate range from 0.005~~' to 5s.'. A similar constitutive equation was obtained [6]. Liu [5,7,8, lo-12,23-251.…”

Section: Introductionsupporting

confidence: 53%

Effect of Hot Deformation Parameters on the Grain Size of Wrought IN718

Zhang¹,

Ma²,

Zhuang³

et al. 1997

Superalloys 718, 625, 706 and Various Derivatives (1997)

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Superalloy IN71 8 is one of the most important aero-materials. It has been widely used to manufacture turbine discs and other important components. Because the microstructure and mechanical properties of IN7 18 forgings are highly sensitive to metallurgical technology and thermomechanical processing(TMP), it is very difficult to control every step of TMP to obtain most favorable mechanical properties and microstructures in IN7 18 forgings. In recent years, more and more attention has been paid to the hot deformation behavior and computer simulation of TMP of superalloy IN718. However, up to now, any perfect model suitable for manufacturing turbine discs has not been found. To set up such a model, it is necessary to formulate the relationship between grain size and hot deformation parameters after a constitutive relationship has been developed. In the present work, isothermal constant speed compression tests of superalloy IN718 were conducted using a computer-controlled MTS machine with temperatures from 960°C to 1040"~, initial strain rates from O.OOls-' to 1.0~~' and engineering strain from 0.1 to 0.7. The deformed specimens were immediately quenched in water to retain the deformation microstructures. The effect of hot deformation parameters on the grain size was analyzed. A formula was developed to express the relationship between grain size and deformation temperature, strain rate and strain.

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Section: Introductionsupporting

confidence: 53%

Effect of Hot Deformation Parameters on the Grain Size of Wrought IN718

Zhang¹,

Ma²,

Zhuang³

et al. 1997

Superalloys 718, 625, 706 and Various Derivatives (1997)

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“…However, it will be seen in the next figures that results of the stress strain calculation in this region are still very useable and provide rather good predictions for the maximum flow stress. F stresses [31,32,33,34,35] at various strains between 10% and 60% over a wide range of temperatures for 718 and 706 respectively. The results are highly satisfactory, even when stresses move the curves into the mixed deformation regime.…”

Section: Discussionmentioning

confidence: 99%

Modelling the Material Properties and Behaviour of Ni- and NiFe-Based Superalloys

Saunders¹,

Guo²,

Miodownik³

et al. 2005

Superalloys 718, 625, 706 and Various Derivatives (2005)

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Over the past decade thermodynamic models have become increasingly used for Ni-and NiFebased superalloys. However, their applicability often falls short from directly providing the information that is actually required. To overcome such limitations a new computer programme has been developed, called JMatPro (an acronym for Java-based Materials Properties software). The properties which can be calculated are wide ranging, including thermo-physical and physical properties (from room temperature to the liquid state), TTT/CCT diagrams, coarsening of ' and ", and mechanical properties. It should be noted that the mechanical properties are calculated as a function of temperature and strain rate up to the melting point. Stress/strain diagrams at any given temperature and strain rate can also be generated. The creep properties that JMatPro provides include steady creep rate, rupture life and rupture strength. A feature of the new programme is that the calculations are based, as far as possible, on sound physical principles rather than purely statistical methods. Thus many of the shortcomings of methods such as regression analysis can be overcome. It allows sensitivity to microstructure to be included for many of the properties and also means that the true inter-relationship between properties can be developed, e.g. in the modelling of creep and precipitation hardening. The purpose of the present paper is to describe the technical background behind the new programme, giving extensive examples of its application and use for superalloys of the 718, 625, 706 and derivative types.

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“…Also, a higher fraction of un-recrystallized grains normally occurs at a low temperature. 13) Therefore, the final forging procedure was performed at a comparatively low temperature of 950°C and was followed immediately by a water quenching process to maintain the un-recrystallized microstructure.…”

Section: Methodsmentioning

confidence: 99%