Flow Stress of bcc Metals over a Wide Range of Temperature and Strain Rates

Abstract

A physical-based model for the flow stress of bcc metals is presented. Here, thermally activated and viscous drag regimes are considered. For the thermally activated component of the flow stress, the diffusion-controlled regime at elevated temperature is also taken into account assuming the non-linear dependence of the activation volume on temperature. The model was applied to A508 (16MND5) steel showing the possibility to accurately describe the variation of the flow stress over the entire temperature range (from 0 K to Tm) and over a wide strain-rate range.

Stress triaxiality effect on void nucleation in ductile metals

“…Similarly, the cohesive critical stress is predicted to increase with decreasing temperature as shown in Figure . Here, the variation of the yield stress with temperature was accounted for using TBRI physically based model . Once the parameters for the cohesive interface are established, the determination of the nucleation strain can be done performing numerical simulation using the unit‐cell model as illustrated in the work.…”

Structure–Property Correlation and Constitutive Description of Structural Steels during Hot Working and Strain Rate Deformation

“…The major drawback of their proposed model was that the predicted curves were not smooth due to the peak strain value. The calculated flow stress based on the proposed equation is shown in Figure 38b Testa et al [231] developed a physical-based model to determine the yield stress as a function of temperature and strain rate for a low carbon A508 steel. Lee et al [232] modified the Shida's constitutive equation by changing the strain-rate hardening function to predict the flow stress behaviour of 0.1% carbon steel at elevated temperatures when the strain rates are higher beyond 100 s −1 .…”

Metal Plasticity and Fatigue at High Temperature

“…As a part of this Special Issue, researchers were invited to submit their innovative research papers aimed at providing a state-of-the-art knowledge on the topic of metal plasticity, creep deformation and fatigue strength of metals operating at high temperatures, with emphasis on both experimental characterization and numerical modeling of material behavior. A total of eleven research papers were published [1][2][3][4][5][6][7][8][9][10][11].…”

“…The authors discuss a stress relaxation constitutive model with the ability to reproduce stress relaxation curves under different process conditions. The paper by Testa et al [10] describes a model to estimate the yield stress at different strain rates and temperatures for metals with body-centered-cubic (bcc) structure. Srnec Novak et al [11] develop a new isotropic model to describe the cyclic hardening/softening plasticity behavior of metals.…”

“…Papers in this Special Issue addressed different types of material, from stainless steel studied by [1,2,4,10], to aluminum alloys investigated by [3,6,9], Ni-based supper alloy in [8], spheroidal graphite iron by [7], and copper alloy discussed in [11].…”