The Hot Deformation Behavior of an As-Cast Alloy 718 Ingot

Weis, M.J.; Mataya, M. C.; Thompson, S. W.; Matlock, David K.

doi:10.7449/1989/superalloys_1989_135_154

Cited by 25 publications

(15 citation statements)

References 16 publications

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“…If the slopes are computed within the same temperature range as mentioned before, the apparent activation energy is approximately 528 kJ/mol. Compared to the previously reported value, for example, 443 kJ/mol by H.Yuan et al [6], 443.2 kJ/mol by Y. Wang et al [7], 400 kJ/mol by S.C. Medeiros et al [8], 423 kJ/mol by M.J. Weis et al [9], activation energy Q in this study is appreciably high, due to the different original microstructure of compress samples. It should be noted from the figure that the scatter increases with increasing strain rate.…”

Section: (C)mentioning

confidence: 39%

Numerical Simulation of Hot Die Forging for IN 718 Disc

Lu¹,

Chen²,

Du³

et al. 2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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Continuous improvements of properties for individual parts are indispensable for perpetual development of aircraft engines. Concerning turbine disc, numerical simulation of forging process is one of the most attractive tools to reduce the cost and time and to improve the properties and the reliability at the same time. In this paper, the hot deformation behavior of IN 718 superalloy has been characterized in the temperature range 900-1020 o C and strain rate range 0.001-0.1 s -1 using isothermal constant strain rate compression tests on process annealed material, with a view to obtain a correlation between grain size and the process parameters. Through a comparison study of two forging methods, temperature-field and strain-field finite element analysis modeling were established, and load-time curves were obtained for a turbine disc under routine and hot die forging process conditions. Results of numerical simulation show that compared to routine forging, hot die forging gives a decrease in total forging force, the temperature-field and strain-field of the turbine disc is more uniform. The effect of cold die on the microstructure is decreased notably under hot die forging condition.

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Section: (C)mentioning

confidence: 39%

Numerical Simulation of Hot Die Forging for IN 718 Disc

Lu¹,

Chen²,

Du³

et al. 2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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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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“…Microstructural development is described using a number of purpose-built routines, which have been incorporated into the code. The dominant mechanisms for microstructural development during ingot breakdown are taken to be static recrystallisation and grain growth, which occur during periods of dwell between successive bites [ 16,171. Previous observations assume that dynamic recrystallisation has a negligible influence on the evolving structure [18,19], which has been demonstrated to occur under specific conditions of temperature and strain-rate [20].…”

Section: The Process Modelmentioning

confidence: 99%

Microstructural Evolution of Nickel-Base Superalloy Forgings during Ingot-to-Billet Conversion: Process Modeling and Validation

Dandre¹,

Walsh²,

Evans³

et al. 2000

Superalloys 2000 (Ninth International Symposium)

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A computer-based process modelling capability has been developed to simulate the evolution of microstructure during ingot-to-billet conversion of nickel-base superalloys. A unique feature of the model is the incorporation of rules describing the dynamic and static recrystallisation phenomena that govern microstructural development. Computational investigations consider the influence of process control parameters such as die velocity and displacement to obtain an optimal microstructure. Furthermore, a comparison is made of the effective strain profiles obtained by squeezing flat versus rounded sections of the workpiece.The details of the model are given with particular emphasis placed on the description of microstructural evolution. A comprehensive testing programme using a purpose built compression testing machine has been carried out to acquire the materials data required for the model. The analysis of the flow curves is described. The microstructural model has been implemented within the three-dimensional visco-plastic Forge3"t finite element software. In order to validate the methodology developed, interrupted cogging trials have been performed. The evolution of microstructure is explained in terms of the cogging model and a more optimal process procedure suggested.Nickel-base superallovs for disc annlications

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The Hot Deformation Behavior of an As-Cast Alloy 718 Ingot

Cited by 25 publications

References 16 publications

Numerical Simulation of Hot Die Forging for IN 718 Disc

Numerical Simulation of Hot Die Forging for IN 718 Disc

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

Microstructural Evolution of Nickel-Base Superalloy Forgings during Ingot-to-Billet Conversion: Process Modeling and Validation

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