Application of dynamic material model hipping of powder compacts
TL;DR: In this article, the authors derived the efficiency of power dissipation for PM compacts for any flow stress data and demonstrated it using the test data of PM Rene 95 alloy.
Abstract: The derivation of efficiency of power dissipation for PM compacts is presented. An accurate evaluation of the efficiency parameter for any flow stress data is described and demonstrated using the test data of PM Rene 95 alloy.
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09 Mar 1989
TL;DR: In this paper, the finite element method was used to analyze the metal forming process and its properties, including plasticity, viscoplasticity, and plane-strain problems.
Abstract: Introduction Metal forming process Analysis and technology in metal forming Plasticity and viscoplasticity Methods of analysis The finite element method (1) The finite element method (2) Plane-strain problems Axisymmetric isothermal forging Steady state processes of extrusion and drawing Sheet metal forming Thermo-viscoplastic analysis Compaction and forging of porous metals Three dimensional problems Preform design in metal forming Solid formulation, comparison of two formulations, and concluding remarks Index.
1,201 citations
TL;DR: In this article, a new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented, which considers the workpiece as a dissipator of power in the total processing system and evaluates the dissipated power co-contentJ = ∫o σ e ⋅dσ from the constitutive equation relating the strain rate (e) to the flow stress (σ).
Abstract: A new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented. The approach in this method is to consider the workpiece as a dissipator of power in the total processing system and to evaluate the dissipated power co-contentJ = ∫o σ e ⋅dσ from the constitutive equation relating the strain rate (e) to the flow stress (σ). The optimum processing conditions of temperature and strain rate are those corresponding to the maximum or peak inJ. It is shown thatJ is related to the strain-rate sensitivity (m) of the material and reaches a maximum value(J max) whenm = 1. The efficiency of the power dissipation(J/J max) through metallurgical processes is shown to be an index of the dynamic behavior of the material and is useful in obtaining a unique combination of temperature and strain rate for processing and also in delineating the regions of internal fracture. In this method of modeling, noa priori knowledge or evaluation of the atomistic mechanisms is required, and the method is effective even when more than one dissipation process occurs, which is particularly advantageous in the hot processing of commercial alloys having complex microstructures. This method has been applied to modeling of the behavior of Ti-6242 during hot forging. The behavior of α+ β andβ preform microstructures has been exam-ined, and the results show that the optimum condition for hot forging of these preforms is obtained at 927 °C (1200 K) and a strain rate of 1CT•3 s•1. Variations in the efficiency of dissipation with temperature and strain rate are correlated with the dynamic microstructural changes occurring in the material.
945 citations
TL;DR: In this paper, a method was developed for the dynamic behavior modeling of P/M superalloys during hot isostatic pressing (HIP) and the power dissipative efficiency during the HIP process was defined as a function of the relative density R and the strain-rate sensitivity index m.
Abstract: A method was developed for the dynamic behavior modeling of P/M superalloys during hot isostatic pressing (HIP). The power dissipative efficiency η during the HIP process was defined as a function of the relative density R and the strain-rate sensitivity index m . Based on the results of isothermal constant strain-rate tests, the microstructure evolution of P/M Rene95 alloy during the HIP process was predicted using the proposed method. The predicted results indicate that HIPing within the temperature range of 1100–1120°C and range of strain rate of 10 −4 –10 −3 ) may eliminate the residual dendrite and ensure consistency in the microstructures and properties of HIP products, these indications being in good agreement with practical experience.
6 citations