β Grain Growth Kinetics of Hot-Rolled TB-13 Alloy

2011 ◽  
Vol 689 ◽  
pp. 472-478 ◽  
Author(s):  
Yue Fei ◽  
Bin Tang ◽  
Hui Chang ◽  
Zhi Shou Zhu ◽  
Zhong Bo Zhou ◽  
...  

A study on the kinetics of β grain growth of a fine-grained, hot-rolled TB-13 alloy was carried out by isochronal and isothermal solution treatments. The grain size of the as-rolled and as-solution-treated samples was determined by metallographic observation using the linear intercept method. The kinetic equations and the Arrhenius-type equation were applied to calculate the β grain growth exponent and the activation energy for β grain growth at special temperatures. The results showed that the β grain growth rate decreased with elongating solution treated time, but increased with increasing solution treated temperature. The β grain growth exponents (n) were 0.394, 0.403 and 0.406 during the solution treated temperatures at 1103K, 1153K and 1203K, respectively. The values of n increased with increasing solution treated temperature and the determined activation energy (Qm) for β grain growth after holding for 0.5h at 1103K-1203K was around 156KJ/mol.

2013 ◽  
Vol 747-748 ◽  
pp. 844-849 ◽  
Author(s):  
Yue Fei ◽  
Xin Nan Wang ◽  
Zhi Shou Zhu ◽  
Jun Li ◽  
Guo Qiang Shang ◽  
...  

Ti-Mo-Nb-Cr-Al-Fe-Si alloy is a new metastable β titanium alloy with excellent combination of strength and ductility. The β grain-growth exponent and the activation energies for β grain growth for the investigated alloy at specified temperature were computed by the kinetic equations and the Arrhenius-type equation. The rate of β grain growth decreases with elongating solution treated time and increases with the increasing solution-treated temperature. The β grain-growth exponents, n, are 0.461, 0.464 and 0.469 at 1113, 1133 and 1153K, respectively. The β grain growth activation energy is determined to be 274 KJ/mol.


2014 ◽  
Vol 59 (3) ◽  
pp. 847-852 ◽  
Author(s):  
Z. Huda ◽  
T. Zaharinie ◽  
H.S.C. Metselaar ◽  
S. Ibrahim ◽  
Goh J. Min

Abstract The Haynes® 718 Ni-base superalloy has been investigated by use of modern material characterization, metallographic and heat treatment equipment. Grain growth annealing experiments at temperatures in the range of 1050 – 1200 oC (1323–1473K) for time durations in the range of 20 min-22h have been conducted. The kinetic equations and an Arrhenius-type equation have been applied to compute the grain-growth exponent n and the activation energy for grain growth, Qg, for the investigated alloy. The grain growth exponent, n, was computed to be in the range of 0.066-0.206; and the n values have been critically discussed in relation to the literature. The activation energy for grain growth, Qg, for the investigated alloy has been computed to be around 440 kJ/mol; and the Qg data for the investigated alloy has been compared with other metals and alloys and ceramics; and critically analyzed in relation to our results.


2013 ◽  
Vol 753 ◽  
pp. 345-348 ◽  
Author(s):  
Hai Wen Luo ◽  
Han Dong ◽  
Ling Feng Chen

Grain growth kinetics in an AISI 347 stainless steel with Nb content up to 0.7%wt was studied during the isothermal holding in the temperature range of 1100-1270°C for various periods. Abnormal grain growth was observed even in the presence of a large amount of precipitates. The kinetics of normal grain growth was tracked by metallographic measurements and fitted by the classical modeling, which led to two important parameters of activation energy Q and growth exponent n derived. Both of them are larger than the usual values for grain growth in the Nb-microalloyed steels due to the much larger content of Nb in the present steel.


2007 ◽  
Vol 534-536 ◽  
pp. 529-532 ◽  
Author(s):  
Dong Gyu Chang ◽  
Joon Hyung Lee ◽  
Jeong Joo Kim

SnO2 ceramics were co-doped with the aliovalent ions of CoO and Nb2O5 and the grain growth behavior of the SnO2 was investigated. When only CoO was doped, the grain growth exponent of SnO2 was 3. As the amount of Nb2O5 increased, the exponent changed from 3 to 2 when 0.505 mol% of Nb2O5 was added. The further addition of Nb2O5 changed the exponent from 2 to 3. When Nb2O5 content was 0.505 mol%, of which the grain growth exponent was 2, it is believed that an iso-electric point is formed without grain boundary segregation, since the respective space charges, generated by Nb5+ and Co3+ might compensate each other.


2015 ◽  
Vol 33 (2) ◽  
pp. 220-229 ◽  
Author(s):  
Berat Yuksel ◽  
T. Osman Ozkan

AbstractGrain growth kinetics in 0.1 to 2 mol % B2O3-added ZnO ceramics was studied by using a simplified phenomenological grain growth kinetics equation Gn = K0 · t · exp(-Q/RT) together with the physical properties of sintered samples. The samples, prepared by conventional ceramics processing techniques, were sintered at temperatures between 1050 to 1250 °C for 1, 2, 3, 5 and 10 hours in air. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 0.1 mol % B2O3-doped ZnO ceramics were found to be 2.8 and 332 kJ/mol, respectively. By increasing B2O3 content to 1 mol %, the grain growth exponent value (n) and the activation energy decreased to 2 and 238 kJ/mol, respectively. The XRD study revealed the presence of a second phase, Zn3B2O6 formed when the B2O3 content was > 1 mol %. The formation of Zn3B2O6 phase gave rise to an increase of the grain growth kinetic exponent and the grain growth activation energy. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 2 mol % B2O3-doped ZnO ceramics were found to be 3 and 307 kJ/mol, respectively. This can be attributed to the second particle drag (pinning) mechanism in the liquid phase sintering.


2012 ◽  
Vol 585 ◽  
pp. 387-391 ◽  
Author(s):  
H. Shivananda Nayaka ◽  
Gajanan P. Chaudhari ◽  
B.S. Sunder Daniel

A detailed study was performed on the grain growth kinetics of ultrafine-grained AZ61 magnesium alloy produced by accumulative roll bonding by carrying out isothermal annealing treatments on the roll bonded samples. Annealing treatments were carried out in the temperature range 423 to 573K for 2 to 120 minutes. As the annealing time and temperature increased, the grain size increased. The effect of annealing temperature and time, on the grain growth can be well explained by the kinetic equation and Arrhenius equation. Based on the experimental results of grain growth during annealing treatments, the grain growth exponent and the activation energy for grain growth were determined. The grain growth kinetic parameters were compared with other magnesium alloys processed by various methods.


2011 ◽  
Vol 66-68 ◽  
pp. 108-113 ◽  
Author(s):  
Chang Jiang Song ◽  
Liang Zhu ◽  
Yuan Yi Guo ◽  
Ke Feng Li ◽  
Feng Mei Sun ◽  
...  

By using a thermal simulator this work investigated grain growth behaviour of a Ti+Nb stabilized 12%Cr ferritic stainless steel at high temperature. The results showed that the grain growth rate was less than 1.8μm/s at the temperature of 1200°C, but it suddenly became very high and reached about 50μm/s when the temperature was 1250°C. Analysis results indicate that grain growth of this steel is affected by the small particles on the grain boundaries, and grain growth exponent is about 3.3. Moreover, the activation energy of the grain growth is when the temperature is above 1250°C. Compared with a 27Cr ferritic stainless steel containing only 0.14%Nb, the grain growth exponent of this steel is greater, and grain initial rapid growth temperature is higher.


2013 ◽  
Vol 545 ◽  
pp. 8-13 ◽  
Author(s):  
Niti Yongvanich ◽  
Visuttipitukul Patama ◽  
Wassa Kijsiri ◽  
Nawarat Pancharoen

Grain growth in ZnO with Bi2O3 addition of up to 1 mol% was examined in great detail for sintering in air. The results are analyzed and compared with previous reports in the context of the simplified phenomenological grain growth kinetics equation along with the physical properties of the sintered ceramics. In spite of the eutectic temperature at 735 °C, high density (> 90%) was not achieved at all Bi2O3 contents; this finding was contradictory to the well-known liquid-phase sintering. At 800 °C, rapid improvement in sintering occurred when increasing the content of Bi2O3 from 0.125mol% to 0.25mol%. Schematic study on weight loss also demonstrated an insignificant level of Bi2O3 volatilization under certain content. Analysis of the grain growth kinetics from isothermal sintering (900 °C - 1,000 °C) revealed strikingly different results in both grain growth exponent (n) and activation energy previously reported in literature. The n values ranged from 3.2 to 5.6 whereas the activation energy from 335 to 598 kJ/mol. Such large disparities were believed to be associated with various mass transport processes. The grain sizes in this study were much smaller than those published in literature (> 10 μm). This size difference, along with other microstructural features, was discussed and correlated in order to explain such anomalies and new findings obtained from the grain growth kinetics results.


2006 ◽  
Vol 20 (25n27) ◽  
pp. 3830-3835 ◽  
Author(s):  
PENG CAO ◽  
DELIANG ZHANG

The grain growth kinetics of nanocrystalline copper thin film samples was investigated. The grain size of nanocrystalline copper samples was determined from the broadening of X-ray spectra. It was found that the grain size increased linearly with isothermal annealing time within the first 10 minutes, beyond which power-law growth kinetics is applied. The activation energy for grain growth was determined by constructing an Arrhenius plot, which shows an activation energy of about 21 – 30 kJ/mol. The low activation energy is attributed to the second phase particle drag and the porosity drag, which act as the pinning force for grain growth in nanocrystalline copper.


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