Determining the Dependence of Grain Boundary Mobility on Misorientation in High Purity Aluminum with Zirconium Additions

2021 ◽  
Author(s):  
David J. Shields
Keyword(s):  
Grain Boundary ◽  
High Purity ◽  
Boundary Mobility ◽  
Grain Boundary Mobility ◽  
High Purity Aluminum

Modeling of Grain-Boundary Mobility and Nucleation Rate during Discontinuous Dynamic Recrystallization in Ni-Nb Alloys and a High-Purity Alloy Derived from SAE 304L

2016 ◽  
Vol 879 ◽  
pp. 1501-1506 ◽  
Author(s):  
David Piot ◽  
Guillaume Smagghe ◽  
Frank Montheillet
Keyword(s):  
Grain Size ◽  
Steady State ◽  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
Nucleation Rate ◽  
High Purity ◽  
Boundary Mobility ◽  
Niobium Content ◽  
Grain Boundary Mobility

A simple mesoscale model has been developed for discontinuous dynamic recrystallization. Each grain is considered in turn as an inclusion, embedded in a homogeneous equivalent matrix, the properties of which are obtained by averaging over all the grains. The model includes: (i) a grain-boundary migration-equation driving the evolution of grain size via the mobility of grain boundaries, which is coupled with (ii) a single-internal-variable (dislocation density) constitutive model for strain hardening and dynamic recovery, and (iii) a nucleation equation governing the total number of grains by the nucleation of new grains. All the system variables tend to asymptotic values at large strains, in agreement with the experimentally observed steady-state regime.With some assumptions, both steady-state stress and grain-size are derived in closed forms, allowing immediate identification of the mobility of grain boundaries and the rate of nucleation. An application to Ni–Nb-pure-binary model alloys and high-purity 304L stainless steel with Nb addition is presented. More specifically on one hand, from experimental steady-state stresses and grain sizes, variations of the grain boundary mobility and the nucleation rate with niobium content are addressed in order to quantify the solute-drag effect of niobium in nickel. And on the other hand, the Derby exponents were investigated varying separately the strain rate or the temperature.

Effect of Hexagonal Crystal Structure Anisotropy on the Selective Grain Boundary Mobility during Texture Formation and Secondary Recrystallization in Zn

2005 ◽  
Vol 495-497 ◽  
pp. 1231-1236
Author(s):  
Vera G. Sursaeva
Keyword(s):  
Grain Boundary ◽  
Secondary Recrystallization ◽  
Stress Fields ◽  
Internal Stresses ◽  
Recrystallization Process ◽  
Boundary Mobility ◽  
Texture Formation ◽  
Hexagonal Crystal ◽  
Grain Boundary Mobility ◽  
Grain Boundary Motion

Texture formation during secondary recrystallization depends on the nature of secondary recrystallization process itself. So microstructure evolution and texture development during secondary recrystallization should be discussed concurrently. The main goal of the paper is studying of the effect of internal stresses on grain boundary motion or, more generally, the interaction of grain boundaries with stress fields and the effect of deformation inhomogeniety on grain boundary mobility during secondary recrystallization. Considering transformation from normal grain growth to secondary recrystallization, the attempt was made to characterize the microstructure and to relate it to the processes of nucleation and growth of new rains. The nucleation process is heterogeneous. The data allow us to assume that the nuclei are strain free grains.

scholarly journals The Influence of Mg-Based Inclusions on the Grain Boundary Mobility of Austenite in SS400 Steel

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 370
Author(s):  
Chih-Ting Lai ◽  
Hsuan-Hao Lai ◽  
Yen-Hao Su ◽  
Fei-Ya Huang ◽  
Chi-Kang Lin ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
High Temperatures ◽  
Growth Curves ◽  
Solute Drag ◽  
Grain Structure ◽  
Growth Equation ◽  
Boundary Mobility ◽  
Grain Boundary Mobility ◽  
Boundary Velocity

In this study, the effects of the addition of Mg to the grain growth of austenite and the magnesium-based inclusions to mobility were investigated in SS400 steel at high temperatures. A high-temperature confocal scanning laser microscope (HT-CSLM) was employed to directly observe, in situ, the grain structure of austenite under 25 torr Ar at high temperatures. The grain size distribution of austenite showed the log-normal distribution. The results of the grain growth curves using 3D surface fitting showed that the n and Q values of the growth equation parameters ranged from 0.2 to 0.26 and from 405 kJ/mole to 752 kJ/mole, respectively, when adding 5.6–22 ppm of Mg. Increasing the temperature from 1150 to 1250 °C for 20 min and increasing the addition of Mg by 5.6, 11, and 22 ppm resulted in increases in the grain boundary velocity. The effects of solute drag and Zener pinning on grain boundary mobility were also calculated in this study.

Grain boundary mobility in bismuth

1961 ◽  
Vol 9 (10) ◽  
pp. 960-961 ◽  
Author(s):  
M.J. Fraser ◽  
R.E. Gold ◽  
W.W. Mullins
Keyword(s):  
Grain Boundary ◽  
Boundary Mobility ◽  
Grain Boundary Mobility
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