scholarly journals The Effect of Grain Size on the Susceptibility Towards Strain Age Cracking of Wrought Haynes® 282®

2020 ◽  
Author(s):  
Fabian Hanning ◽  
Gurdit Singh ◽  
Joel Andersson
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Heat Treating ◽  
Boundary Carbide ◽  
Isothermal Exposure ◽  
Fourfold Increase ◽  
Local Stresses ◽  
Material Ductility

The effect of grain size on the suceptibility towards strain age cracking (SAC) has been investigated for Haynes® 282® in the tempeature range of 750 to 950∘C after isothermal exposure up to 1800s. Grain growth was induced by heat treating the material at 1150∘C for 2h, resulting in a fourfold increase in grain size. Hardness was significanlty reduced after heat treatment as compared to mill-annealed material. Large grain size resulted in intergranular fracture over a wider temperature range than small grain size material. Ductility was lowest at 850∘C, while lower values were observed to be correlated to increased grain size. The rapid formation of grain boundary carbide networks in Haynes® 282® is found to be not able to compensate for higher local stresses on grain boundaries due to incresed grain size.

The Effect of Heat-Treatment on Thermal Conductivity of Silicon Nitride Ceramics

2011 ◽  
Vol 484 ◽  
pp. 52-56
Author(s):  
Katsumi Yoshida ◽  
Yuki Sekimoto ◽  
Keiichi Katayama ◽  
Thanakorn Wasanapiarnpong ◽  
Masamitsu Imai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Glassy Phase ◽  
Boundary Phase ◽  
Sintering Additives ◽  
Heat Treated ◽  
Si3n4 Ceramics

Alpha- or beta-Si3N4 powder with larger grain size was uses as starting material, and the effect of heat-treatment on thermal conductivity of Si3N4 ceramics using MgO, Y2O3 and SiO2 as sintering additives was investigated in terms of their microstructure and the amount of grain boundary phase. Most of the components derived from sintering additives existed as glassy phase in sintered Si3N4. After heat-treatment at 1950oC for 8 h, the amount of glassy phase significantly decreased, and then small amount of glassy phase existed in Si3N4 ceramics was crystallized as Y2O3 and Y2Si3N4O3. In the case of Si3N4 ceramics using SN-7 powder, thermal conductivity of heat-treated Si3N4 was around twice of the value of sintered Si3N4, and the thermal conductivity was increased from 41.4 to 87.2 W/m•K due to not only the reduction of grain boundary phase but also the grain growth. In the case of Si3N4 using SN-F1 powder, thermal conductivity of Si3N4 ceramics was also significantly increased from 36.0 to 73.2 W/m•K after heat-treatment. In this case, the reduction of grain boundary phase mainly affected the thermal conductivity of Si3N4 ceramics because the grain size of heat-treated Si3N4 was nearly the same as that of sintered Si3N4. The reduction of grain boundary phase from Si3N4 was effective for the improvement of their thermal conductivity in addition to grain growth of Si3N4.

Effect of Post Weld Heat Treatment on Fusion and Heat Affected Zone Microstructure and Mechanical Properties of Inconel X-750 Welds

2011 ◽  
Vol 214 ◽  
pp. 108-112 ◽  
Author(s):  
Prachya Peasura ◽  
Bovornchok Poopat
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
Aging Temperature ◽  
Post Weld Heat Treatment ◽  
High Aging Temperature ◽  
Zone Microstructure

The Inconel X-750 indicates good hot corrosion resistance, high stability and strength at high temperatures and for this reason the alloy is used in manufacturing of gas turbine hot components. The objective of this research was study the effect of post weld heat treatment (PWHT) on fusion zone and heat affected zone microstructure and mechanical properties of Inconel X-750 weld. After welding, samples were solutionized at 1500 0C. Various aging temperature and times were studied. The results show that aging temperature and time during PWHT can greatly affect microstructure and hardness in fusion zone and heat affected zone. As high aging temperature was used, the grain size also increased and M23C6 at the grain boundary decreased. This can result in decreased of hardness. Moreover excessive aging temperature can result in increasing MC carbide intensity in parent phase (austenite). It can also be observed that M23C6 at the grain boundary decreased due to high aging temperature. This resulted in decreasing of hardness of weld metal and heat affected zone. Experimental results showed that the aging temperature 705 0C aging time of 24 hours provided smaller grain size, suitable size and intensity of MC carbide resulting in higher hardness both in weld metal and HAZ.

scholarly journals On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1193 ◽  
Author(s):  
Kolli ◽  
Javaheri ◽  
Kömi ◽  
Porter
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Carbon Content ◽  
Double Loop ◽  
Boundary Carbide ◽  
Self Healing ◽  
Chromium Depletion ◽  
Electrochemical Potentiokinetic Reactivation

The effect of grain size in the range 72 to 190 μm and carbon content in the range 0.105–0.073 wt.% on the intergranular corrosion of the austenitic stainless steel 301 has been investigated. Grain boundary chromium depletion has been studied directly using energy dispersive X-ray spectroscopy combined with scanning transmission electron microscopy and indirectly using double loop electrochemical potentiokinetic reactivation tests. In addition, chromium depletion has been modelled using the CALPHAD Thermo-Calc software TC-DICTRA. It is shown that the degree of sensitization measured using the double loop electrochemical potentiokinetic reactivation tests can be successfully predicted with the aid of a depletion parameter based on the modelled chromium depletion profiles for heat treatment times covering both the sensitization and de-sensitization or self-healing. Additionally, along with intergranular M23C6 carbides, intragranular M23C6 and Cr2N nitrides that affect the available Cr for grain boundary carbide precipitation were also observed.

Grain Growth Behaviour Of Nanocrystalline Nickel

1991 ◽  
Vol 238 ◽  
Author(s):  
A. M. El-Sherik ◽  
K. Boylan ◽  
U. Erb ◽  
G. Palumbo ◽  
K. T. Aust
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Thermal Stabilization ◽  
Growth Behaviour ◽  
In Situ Electron Microscopy ◽  
Thermal Stability Of

ABSTRACTThe thermal stability of electrodeposited nanocrystalline Ni-1.2%P and Ni-0.12%S alloys is evaluated by in-situ electron microscopy studies. Isothermal grain size versus annealing time curves at 573K and 623K show an unexpected thermal stabilization in form of a transition from rapid initial grain growth to negligible grain growth. This behaviour is discussed in terms of the various grain boundary drag mechanisms which may be operative in these alloys.

Effect of Heat Treatment Temperature on the Spinning Structure and Properties of a Cu–Sn Alloy

2019 ◽  
Vol 26 (1) ◽  
pp. 29-35
Author(s):  
Jinli Liu ◽  
Wenyuan Zheng ◽  
Huiqin Yin
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Grain Boundary ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Recrystallization Temperature ◽  
Boundary Orientation ◽  
Different Temperatures ◽  
Alloy Microstructure ◽  
Electron Back Scattered Diffraction

AbstractA thin-walled copper (Cu)–tin (Sn) alloy cylinder was treated after spinning at 200–400°C for 0.5 h. The characteristics of the alloy microstructure under different temperatures were analyzed through electron back-scattered diffraction. The results were as follows. The grain size at 200–300°C decreases as the heat treatment temperature rises, but the grain size at 400°C increases. At 200–300°C, the microstructure primarily consists of deformed grains. It is found that the main reason for the formation of high-angle grain boundaries (HAGBs) is static recrystallization. For the grain boundary orientation differential, the low-angle sub-grain boundary gradually grows into the HAGB, and multiple annealing twin Σ9 boundaries appear. Grain orientation is generally random at any temperature range. The mechanical property test indicated that, at the upper critical recrystallization temperature of 300°C, the elongation of the Cu–Sn alloy gradually increases, and its yield strength and ultimate tensile strength rapidly decrease.

Preparation and Microstructure Evolution of Both Freestanding and Supported TiO2 Thin Films

2002 ◽  
Vol 17 (6) ◽  
pp. 1520-1528 ◽  
Author(s):  
Chen-Lung Fan ◽  
Daniel Ciardullo ◽  
Jay Paladino ◽  
Wayne Huebner
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Grain Size ◽  
Grain Growth ◽  
Anatase Phase ◽  
Rutile Phase ◽  
Tio2 Thin Films ◽  
Cover Glass ◽  
Citrate Complex ◽  
Phase Development

Thin films of TiO2 were fabricated by spin-coating silicon wafers and cover glass with a titanium citrate complex precursor. The grain growth and phase development of both freestanding and supported films were studied using a combination of atomic force microscopy, x-ray diffraction, and transmission electron microscopy. Freestanding films prepared at 400 °C possess only the anatase phase, while supported films treated under the same conditions formed a small amount of the rutile phase. After heat treatment at various temperatures, results indicated that porosity was introduced into the films when the grain size grew close to the film thickness. Grain growth studies show that the grain size of the freestanding film underwent a drastic increase during the transformation from anatase to rutile. The grain size of the supported films did not show an abrupt change upon heat treatment. The grain size of the freestanding films treated at 900 °C was approximately three times larger than that of the supported films.

Phase Field Simulation of Grain Growth with Particle Pinning

2016 ◽  
Vol 724 ◽  
pp. 8-11
Author(s):  
Chun Yu Teng ◽  
Yun Fu ◽  
Zhan Yong Ren ◽  
Yong Hong Li ◽  
Yun Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Phase Field ◽  
Particle Number ◽  
Boundary Energy ◽  
Service Condition ◽  
Second Phase ◽  
Pinning Effect

The properties of alloys depend on its microstructure, such as the size of grains. In general, the balanced mechanical properties of alloys can be obtained with small grain size. While the grain size of alloys may increases under heat treatment, thermal mechanical processing and service condition of high temperature, i.e., the grain growth is inevitable. The effort of most research is to control the rate of grain growth and avoid abnormal grain growth. For example, pinning the grain boundary and reduce its mobility with the second phase particles in order to prevent grain growth. Therefore, the properties of the alloys will not decreases dramatically and the structure retains a high degree of integrity. The details of grain growth with particle pinning were investigated by phase field simulations in the present paper. It is found that, with the same size of pinning particles, the pinning effect increases with the increases of the pinning particle number. With the same pinning particle number, the pinning effect increases with the increases of pinning particle size. Under the same total volume of pinning particles while different particle size and number, the pinning effect is complicated and it will be discussed in details. The pinning effect decreases with the increases of grain boundary energy. These findings could shed light on the understanding of the grain growth kinetics with particle pinning.

scholarly journals A brief overview on grain growth of bulk electrodeposited nanocrystalline nickel and nickel-iron alloys

2019 ◽  
Vol 58 (1) ◽  
pp. 98-106
Author(s):  
Haitao Ni ◽  
Jiang Zhu ◽  
Zhaodong Wang ◽  
Haiyang Lv ◽  
Yongyao Su ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Growth Process ◽  
Boundary Migration ◽  
Thermal Conditions ◽  
Iron Alloys ◽  
Nanocrystalline Nickel ◽  
Nickel Iron ◽  
Average Grain Size

Abstract This review focuses on grain growth behaviors and the underlying mechanisms of bulk electrodeposited nanocrystalline nickel and nickel-iron alloys. Effects of some important factors on grain growth are described. During thermal-induced grain growth process, grain boundary migration plays a key role. For similar thermal conditions, due to grain boundary mobility with solute drag, limited grain growth occurs in nanocrystalline alloys, as compared to pure metals. Nonetheless, in the case of stress-induced grain growth process, there are a variety of mechanisms in samples having various deformation histories. As an example the grain growth of nanocrystalline nickel and Ni-20%Fe alloy with nearly the same grain-size distribution and average grain size is compared in this paper. Thermal analysis indicates nanocrystalline nickel is much more prone to rapid grain growth than nanocrystalline Ni-20%Fe alloy. Nevertheless, grain growth of nanocrystalline Ni-20%Fe is found to be more pronounced than nanocrystalline nickel during rolling deformation.

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.

On the theory of the effect of precipitate particles on grain growth in metals

1966 ◽  
Vol 294 (1438) ◽  
pp. 298-309 ◽  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Energy ◽  
Second Phase ◽  
Pinning Force ◽  
Essential Difference ◽  
The Matrix ◽  
Critical Particle Size

A theoretical model of the energy changes accompanying grain boundary movement has been developed. It has been shown that small boundary movements will reduce the energy of a polycrystalline metal only when there is a heterogeneous grain size. The pinning force exerted by precipitate particles of a second phase on the grain boundary has also been considered. The release of grain boundary energy which accompanies grain growth has been considered as a source of energy for the unpinning process. The theory predicts a critical particle size which is dependent on the volume fraction of second phase, the matrix grain size, and the degree of heterogeneity of the matrix. Coalescence of the precipitate to a size in excess of the critical radius will permit grain growth to occur. Theoretical predictions of the critical particle size are in good agreement with values determined experimentally. The essential difference between grain growth and secondary recrystallization is indicated by the theory.

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