Dynamic Grain Growth in Superplastic Y-TZP and Al2O3/YTZ

1990 ◽  
Vol 196 ◽  
Author(s):  
T. G. Nieh ◽  
C. M. Tomasello ◽  
J. Wadsworth
Keyword(s):  
Growth Rate ◽  
Grain Size ◽  
Grain Growth ◽  
Kinetic Constant ◽  
Boundary Energy ◽  
Tetragonal Zirconia ◽  
Grain Boundary Energy ◽  
Fine Grained ◽  
Dynamic Grain Growth ◽  
Similar Equation

ABSTRACTBoth static and dynamic grain growth have been studied during superplastic deformation of fine-grained yttria-stabilized tetragonal zirconia (Y-TZP) and alumina reinforced yttria-stabilized tetragonal zirconia (Al2O3/YTZ). Grain growth was observed in both materials at temperatures above 1350° C. In the case of Y-TZP, both static and dynamic grain growth were found to obey a similar equation of the form: where D is the instantaneous grain size, Do is the initial grain size, t is the time, and k is a kinetic constant which depends primarily on temperature and grain boundary energy. The activation energies for Y-TZP were approximately 580 and 520 kJ/mol, for static and dynamic grain growth, respectively. In the case of Al2O3/YTZ, it was found that the grain growth rate for the Al2O3 phase was slower than that for the ZrO2 phase. The growth rate of the ZrO2 phase in Al2O3/YTZ is, however, similar to that in monolithic ZrO2, i.e., Y-TZP.

The effect of excess neodymia on the grain growth of Nd1+xBa2−xCu3Oy solid solutions

1998 ◽  
Vol 13 (10) ◽  
pp. 2819-2832 ◽  
Author(s):  
Russell B. Rogenski ◽  
Kenneth H. Sandhage ◽  
Alexander L. Vasiliev ◽  
Eric P. Kvam
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Energy ◽  
Grain Boundary Energy ◽  
Detectable Change ◽  
Fine Grained ◽  
Average Grain Size ◽  
Second Phases

The grain growth of dense, fine-grained Nd1+xBa2−xCu3Oy (x = 0.1−0.4) specimens has been examined in pure O2(g) at 938 °C and 967 °C. No detectable change in average grain size was observed for Nd1.4Ba1.6Cu3Oy within 72 h at 967 °C; however, a significant increase in average grain size developed between 18 and 24 h at 967 °C for Nd1.3Ba1.7Cu3Oy, and within 8−12 h at ≤967 °C for Nd1.2Ba1.8Cu3Oy and Nd1.1Ba1.9Cu3Oy. Microstructural analyses revealed that sudden changes in average grain size coincided with the formation of relatively large (abnormal) grains. A broadening of the grain size distribution was also observed. TEM analyses revealed that grain boundaries were free of second phases. The possible role of anisotropy in grain boundary energy and/or mobility on grain growth is discussed.

Effect of Grain Boundary Energy in Recrystallization Simulation by Phase Field Method

2020 ◽  
Vol 993 ◽  
pp. 953-958
Author(s):  
Yan Wu ◽  
Ren Chuang Yan ◽  
Er Wei Qin ◽  
Wei Dong Chen
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Phase Field ◽  
Boundary Energy ◽  
Phase Field Model ◽  
Field Method ◽  
Phase Field Method ◽  
Grain Boundary Energy ◽  
Average Grain Size

In this paper, the effect of grain boundary energy in AZ31 Mg alloy with multi-order parameters phenomenological phase field model has been discussed during the progress of recrystallization. The average grain size of the recrystallization grain at a certain temperature and a certain restored energy but various grain boundary energies have been studied, and the simulated results show that the larger the grain boundary energy is, the larger the average grain size will be, and the speed of grain growth will increase with the increase of grain boundary energy. Additionally, temperature will also increase the grain growth rate.

The Relationship between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain Size in Ca-Doped Yttria

2013 ◽  
Vol 753 ◽  
pp. 87-92 ◽  
Author(s):  
Stephanie A. Bojarski ◽  
Jocelyn Knighting ◽  
Shuai Lei Ma ◽  
William Lenthe ◽  
Martin P. Harmer ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Size Distribution ◽  
Grain Growth ◽  
Lower Energy ◽  
Boundary Energy ◽  
Grain Boundary Energy ◽  
Entire Sample ◽  
Small Grains ◽  
The Relationship

The thermal groove technique has been used to measure relative grain boundary energies in two 100 ppm Ca-doped yttria samples. The first has a normal grain size distribution and the boundaries have a bilayer of segregated Ca. In the second sample, there is a combination of large grains and small grains. The boundaries around the large grains are known to have an intergranular film. The results show that the relative energies of boundaries in the sample with normal grain growth and the boundaries around small grains far from larger grains in the second sample are similar. Also, boundaries surrounding the largest grains and small grains immediately adjacent to them have the same and significantly lower energies. The results indicate that grain boundaries with an intergranular film have a lower energy than those with bilayer segregation and that the intergranular film extends beyond the periphery of the largest grains, but not throughout the entire sample.

Anti-thermal grain growth in SrTiO3: Coupled reduction of the grain boundary energy and grain growth rate constant

2018 ◽  
Vol 149 ◽  
pp. 11-18 ◽  
Author(s):  
Madeleine N. Kelly ◽  
Wolfgang Rheinheimer ◽  
Michael J. Hoffmann ◽  
Gregory S. Rohrer
Keyword(s):  
Growth Rate ◽  
Grain Boundary ◽  
Grain Growth ◽  
Rate Constant ◽  
Boundary Energy ◽  
Growth Rate Constant ◽  
Grain Boundary Energy

Influence of grain boundary energy on the grain size evolution in nanocrystalline materials

2009 ◽  
Vol 475 (1-2) ◽  
pp. 893-897 ◽  
Author(s):  
Zheng Chen ◽  
Feng Liu ◽  
Wei Yang ◽  
Haifeng Wang ◽  
Gencang Yang ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Nanocrystalline Materials ◽  
Boundary Energy ◽  
Grain Boundary Energy ◽  
Size Evolution

Grain boundary energy changes during grain growth in nickel and 316L austenitic steel

1986 ◽  
Vol 2 (2) ◽  
pp. 106-109 ◽  
Author(s):  
W. Przetakiewicz ◽  
K. J. Kurzydłowski ◽  
M. W. Grabski
Keyword(s):  
Grain Boundary ◽  
Austenitic Steel ◽  
Grain Growth ◽  
Boundary Energy ◽  
Grain Boundary Energy

Orientation Selectivity of Secondary Recrystallization in Grain-Oriented Silicon Steel

2013 ◽  
Vol 753 ◽  
pp. 337-340 ◽  
Author(s):  
Yoshiyuki Ushigami ◽  
Yoshihiro Arita ◽  
Kohsaku Ushioda
Keyword(s):  
Grain Size ◽  
Boundary Energy ◽  
Secondary Recrystallization ◽  
Silicon Steel ◽  
Orientation Selectivity ◽  
Pinning Force ◽  
Grain Boundary Energy ◽  
Deviation Angle ◽  
The Matrix ◽  
Goss Orientation

It has been observed that grain size of Goss secondary grain has a strong correlation with deviation angle from the exact Goss orientation and sharper Goss grain has larger grain diameter. This orientation selectivity of secondary recrystallization has been investigated with the statistical model of grain growth in which inhibitor and texture are taken into account. The model assumes that sharper Goss grain has a higher frequency of CSL boundaries to the matrix grains and thus has lower statistical grain boundary energy and suffers lower pinning force from the inhibitor. The analysis showed that this model successfully explains orientation selectivity and depicts the effect of inhibitor and texture.

Microstructural Design for Attaining High-Strain-Rate Superplasticity in Oxide Materials

2006 ◽  
Vol 45 ◽  
pp. 923-932
Author(s):  
Keijiro Hiraga ◽  
Byung Nam Kim ◽  
Koji Morita ◽  
Tohru Suzuki ◽  
Yoshio Sakka
Keyword(s):  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Spinel Phase ◽  
Tetragonal Zirconia ◽  
Secondary Phases ◽  
Cavitation Damage ◽  
Size Refinement ◽  
Dynamic Grain Growth

Factors limiting the strain rate of superplastic deformation in oxide ceramics are discussed from existing knowledge about the mechanisms of high-temperature plastic deformation and intergranular cavitation. The discussion leads to the following guide: simultaneously controlling the initial grain size, diffusivity, dynamic grain growth, homogeneity of microstructure and the number of residual defects is essential to attain high-strain-rate superplasticity. Along this guide, high-strain-rate superplasticity (HSRS) is attainable in some oxides consisting of tetragonal zirconia, α-alumina and a spinel phase: tensile ductility reached 300-2500% at a strain rate of 0.01-1.0 s-1. Post-deformation microstructure indicates that some secondary phases may suppress cavitation damage and thereby enhance HSRS. The guide is also essential to lower the limit of deformation temperature for a given strain rate. In monolithic tetragonal zirconia, grain-size refinement combined with doping of aliovalnt cations such as Mg2+, Ti4+ and Al3+ led to HSRS at 1350 °C.

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