scholarly journals Grain Boundary Sliding in High-Temperature Deformation of Directionally Solidified hcp Zn Alloys and Implications for the Deformation Mechanism of Earth's Inner Core

2018 ◽  
Vol 123 (1) ◽  
pp. 189-203 ◽  
Author(s):  
Michael I. Bergman ◽  
James Yu ◽  
Daniel J. Lewis ◽  
Grant K. Parker
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Inner Core ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Directionally Solidified ◽  
Boundary Sliding ◽  
Earth’S Inner Core ◽  
Zn Alloys

Grain boundary sliding at high temperature deformation in cold-rolled ODS ferritic steels

2014 ◽  
Vol 452 (1-3) ◽  
pp. 628-632 ◽  
Author(s):  
Yoshito Sugino ◽  
Shigeharu Ukai ◽  
Bin Leng ◽  
Naoko Oono ◽  
Shigenari Hayashi ◽  
...  
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Ferritic Steels ◽  
Boundary Sliding ◽  
Cold Rolled

High temperature deformation behavior of titanium samples with superplastic layer

1995 ◽  
Vol 10 (4) ◽  
pp. 864-869 ◽  
Author(s):  
M.G. Zelin ◽  
Q. Li ◽  
R.Z. Valiev ◽  
P. Lukač ◽  
A.K. Mukherjee
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Layer By Layer ◽  
Boundary Sliding

The progress of high temperature deformation in samples of two commercial titanium alloys with superplastic (SP) structure, non-SP structure, and with an SP layer sandwiched between the non-SP regions has been studied on the scale of the entire deformed volume and on the scale of grain groups. The results of mechanical behavior showed that samples with SP layer exhibit higher stress level than those with completely SP structure and higher strain rate sensitivity than those with completely non-SP structure. Samples with SP layer demonstrate a more pronounced deccrease in strain rate sensitivity with the increase of strain than samples with completely SP structure. Deformation in the SP layer proceeds as grain shear in a layer-by-layer manner. The deformation of SP layer through the operation of cooperative grain boundary sliding, i.e., sliding of grain groups as an entity along certain grain boundary surfaces, provides the main contribution to the total strain.

Grain Boundary Sliding Phenomenon and Its Effect on High Temperature Ductility of Ni-Base Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 2858-2863 ◽  
Author(s):  
E.A. Torres ◽  
R. Caram ◽  
Antonio J. Ramirez
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Materials Science ◽  
Grain Boundary Sliding ◽  
Atomic Scale ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Digital Videos ◽  
Boundary Sliding

The structural materials phase transformations and failure mechanisms have been under scrutiny for many years. However, the advent of new and more powerful techniques is always making possible to address unsolved problems. Nowadays, the implementation of sophisticated in-situ electron microscopy tests is providing new insights in several fields of chemistry, physics, and materials science by allowing direct observation of a wide variety of phenomena at submicron and even atomic scale. These experiments may involve controlled temperature and atmospheres, mechanical loading, magnetic and/or electric field among other conditions that are imposed to the sample while its response or evolution is studied. An in-situ high temperature deformation experiment was developed and adapted within the vacuum chamber of a scanning electron microscope (SEM). This setup was used to study the grain boundary sliding (GBS) mechanism and its effect on the high temperature cracking phenomenon known as ductility-dip cracking (DDC). The Ni-base filler metals AWS A5.14, ERNiCrFe-7 and ERNiCr-3, which correspond to alloys 690 and 600, respectively, were studied within the temperature range between 700 and 1000 °C. Analysis of the recorded digital videos that registered the high temperature deformation made possible differentiating and quantifying, with submicron resolution, two different components of GBS. The designated pure-GBS and deformation-GBS components were described and quantified. In addition, the GBS relationship with the material high temperature ductility and the DDC failure mechanism was established.

Intergranular Cracking in Alloy 690 with Nb, Mo, and Hf Additions: In Situ SEM High Temperature Deformation Study

2012 ◽  
Vol 706-709 ◽  
pp. 945-950 ◽  
Author(s):  
Jimy S. Unfried ◽  
Antonio Jose Ramirez
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Intergranular Cracking ◽  
Alloy 690 ◽  
Deformation Test ◽  
Boundary Sliding

The microstructure behavior during high temperature deformation of Ni-base alloys based on alloy 690 modified with Nb, Mo, and Hf additions were studied. Optical and electron microscopy were used to characterize these materials and the results were compared with Calphad-based modeling results. The alloys behavior was studied between 500 and 1000 °C using an in-situ high temperature deformation test. The role of precipitates on the grain boundary morphology and their effect on grain boundary sliding and the mechanism of ductility-dip cracking are discussed. Both, undulated grain boundaries and primary intra-granular precipitates improved the alloy DDC resistance.

scholarly journals Grain boundary sliding mechanism during high temperature deformation of AZ31 Magnesium alloy

2016 ◽  
Vol 669 ◽  
pp. 171-177 ◽  
Author(s):  
Peiman Shahbeigi Roodposhti ◽  
Apu Sarkar ◽  
Korukonda Linga Murty ◽  
Harold Brody ◽  
Ronald Scattergood
Keyword(s):  
High Temperature ◽  
Magnesium Alloy ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Az31 Magnesium Alloy ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Sliding Mechanism ◽  
Boundary Sliding

Evaluation of Plastic Workability Limit of Magnesium Alloy by Cavitations in High Temperature Uni and Biaxial Test

2012 ◽  
Vol 735 ◽  
pp. 67-72
Author(s):  
Kunio Funami ◽  
Daisuke Yamashita ◽  
Kohji Suzuki ◽  
Masafumi Noda
Keyword(s):  
Fine Structure ◽  
High Temperature ◽  
Magnesium Alloy ◽  
Grain Boundary ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Az31 Magnesium Alloy ◽  
Temperature Deformation ◽  
Alloy Plate ◽  
Boundary Sliding

Abstract. This study examined the critical plastic formability limit of a fine-structure AZ31 magnesium alloy plate under warm and high temperature based on the strength of a magnesium alloy that has cavities at room temperature. The cyclic hot free-forging process as pre-form working following rolling at a light reduction ratio fabricated a fine-structure AZ31 magnesium alloy plate. The appearance of the cavities was examined in detail together with changes in the structure and preparation methods before further damage at high temperatures with increasing uni-and biaxial plastic deformation. The allowable deformation limit in the super plasticity process can be estimated from the strength of the deformed material and forming limit diagram (FLD) at room temperature. During high-temperature deformation, cavities are produced by stress concentrations at grain boundary triple points and striation bands due to grain boundary sliding. The cavitations growth behavior is dependent upon deformation conditions, and a high percentage of large cavities occupy the sample surface as a large amount of grain boundary sliding is present, i.e., as uniform elongation grows larger, the cavity size also increases. In a case where 200% uniaxial strain was applied to a fine-grained structure material at a temperature of 623K under a strain rate of 10-4s-1, the tensile strength at room temperature decreased about 13%, and elongation was 10% less, compared with that of a material to which no load was applied due to the influence of cavities. In a case of biaxial deformation, the values were 28% lower. It is possible to draw a FLD based on the cavity incidence fraction .

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