Grain Boundary Shear Coupling is Not a Grain Boundary Property

Grain boundary shear coupling is not a grain boundary property

Acta Materialia ◽

10.1016/j.actamat.2019.01.040 ◽

2019 ◽

Vol 167 ◽

pp. 241-247 ◽

Cited By ~ 13

Author(s):

Kongtao Chen ◽

Jian Han ◽

Spencer L. Thomas ◽

David J. Srolovitz

Keyword(s):

Grain Boundary ◽

Boundary Property ◽

Boundary Shear ◽

Shear Coupling

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071193 ◽

1973 ◽

Vol 31 ◽

pp. 150-151

Author(s):

J. E. Doherty ◽

A. F. Giamei ◽

B. H. Kear ◽

C. W. Steinke

Keyword(s):

Grain Boundary ◽

Room Temperature ◽

Nickel Base Superalloy ◽

Boundary Shear ◽

Room Temperature Ductility ◽

Solid Solution Matrix ◽

Nickel Base ◽

Solution Matrix ◽

Different Levels ◽

Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Grain-boundary shear-migration coupling. II. Geometrical model for general boundaries

Acta Materialia ◽

10.1016/j.actamat.2009.01.023 ◽

2009 ◽

Vol 57 (8) ◽

pp. 2390-2402 ◽

Cited By ~ 91

Author(s):

D. Caillard ◽

F. Mompiou ◽

M. Legros

Keyword(s):

Grain Boundary ◽

Geometrical Model ◽

Boundary Shear

Mechanical Properties of Novel Nanocrystalline Materials

10.1115/imece2001/md-24806 ◽

2001 ◽

Author(s):

J. Narayan ◽

H. Wang ◽

A. Kvit

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Nanocrystalline Materials ◽

High Surface ◽

Grain Boundary Sliding ◽

Boundary Shear ◽

Functionally Gradient ◽

Boundary Sliding ◽

First Time ◽

Critical Grain Size

Abstract We have synthesized nanocrystalline thin films of Cu, Zn, TiN, and WC having uniform grain size in the range of 5 to 100 nm. This was accomplished by introducing a couple of manolayers of materials with high surface and have a weak interaction with the substrate. The hardness measurements of these well-characterized specimens with controlled microstructures show that hardness initially increases with decreasing grain size following the well-known Hall-Petch relationship (H∝d−½). However, there is a critical grain size below which the hardness decreases with decreasing grain size. The experimental evidence for this softening of nanocrystalline materials at very small grain sizes (referred as reverse Hall-Petch effect) is presented for the first time. Most of the plastic deformation in our model is envisioned to be due to a large number of small “sliding events” associated with grain boundary shear or grain boundary sliding. This grain-size dependence of hardness can be used to create functionally gradient materials for improved adhesion and wear among other improved properties.

Interpretation of Upper Yield Point in Polycrystalline Ferritic Steel Based on the Critical Grain Boundary Shear Stress

Tetsu-to-Hagane ◽

10.2355/tetsutohagane.tetsu-2019-105 ◽

2020 ◽

Vol 106 (6) ◽

pp. 382-390

Author(s):

Toshihiro Tsuchiyama ◽

Satoshi Araki ◽

Setsuo Takaki

Keyword(s):

Shear Stress ◽

Grain Boundary ◽

Yield Point ◽

Ferritic Steel ◽

Boundary Shear ◽

Boundary Shear Stress

In situ atomic scale mechanisms of strain-induced twin boundary shear to high angle grain boundary in nanocrystalline Pt

Ultramicroscopy ◽

10.1016/j.ultramic.2018.08.022 ◽

2018 ◽

Vol 195 ◽

pp. 69-73 ◽

Cited By ~ 2

Author(s):

Lihua Wang ◽

Jiao Teng ◽

Yu Wu ◽

Xuechao Sha ◽

Sisi Xiang ◽

...

Keyword(s):

Grain Boundary ◽

Twin Boundary ◽

Atomic Scale ◽

High Angle ◽

Boundary Shear

Notched Tensile Fracture of Ti-6Al-6V-2Sn Welds at Elevated Temperature

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1137 ◽

2009 ◽

Vol 79-82 ◽

pp. 1137-1140 ◽

Cited By ~ 1

Author(s):

Lv Wen Tsay ◽

C.L. Hsu

Keyword(s):

Elevated Temperature ◽

Grain Boundary ◽

Tensile Tests ◽

Tensile Fracture ◽

Boundary Shear ◽

Dimple Fracture ◽

Laser Welds ◽

Fracture Appearance ◽

Notched Tensile Strength ◽

Increasing Temperature

The notched tensile tests of Ti-6Al-6V-2Sn laser welds with distinct post-weld heat treatments (PWHTs) were carried out at 150, 300, and 450oC and the results were also compared with the mill-annealed base metal (BM). The BM specimen had the highest notched tensile strength (NTS) among the specimens being tested at room temperature but became the lowest at 450oC. At/above 150oC, all welds showed a decrease in NTS with increasing temperature. The cracks tended to grow along the α / β interface in the BM specimen. The formation of premature fine pores at the grain boundary in the weld with PWHT at 704oC accounted for the intergranular dimple fracture of the specimen. The fracture appearance of the as-welded (AW) and the 482oC-aged (W-482) welds comprised of mainly transgranular dimple and increased the extent of grain boundary shear at elevated temperature.

232 Atomistic study of relationship between grain boundary property and hydrogen trapping ability

The Proceedings of The Computational Mechanics Conference ◽

10.1299/jsmecmd.2008.21.448 ◽

2008 ◽

Vol 2008.21 (0) ◽

pp. 448-449

Author(s):

Marika RIKU ◽

Ryosuke MATSUMOTO ◽

Shinya TAKETOMI ◽

Noriyuki MIYAZAKI

Keyword(s):

Grain Boundary ◽

Boundary Property ◽

Hydrogen Trapping ◽

Atomistic Study

Grain boundary shear–migration coupling—I. In situ TEM straining experiments in Al polycrystals

Acta Materialia ◽

10.1016/j.actamat.2009.01.014 ◽

2009 ◽

Vol 57 (7) ◽

pp. 2198-2209 ◽

Cited By ~ 140

Author(s):

F. Mompiou ◽

D. Caillard ◽

M. Legros

Keyword(s):

Grain Boundary ◽

In Situ Tem ◽

Boundary Shear

Novel Nanocrystalline Composites

Materials: Processing, Characterization and Modeling of Novel Nano-Engineered and Surface Engineered Materials ◽

10.1115/imece2002-39371 ◽

2002 ◽

Author(s):

J. Narayan

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Tungsten Carbide ◽

Nickel Aluminide ◽

Processing Technique ◽

High Temperature Strength ◽

Softening Behavior ◽

Boundary Shear ◽

Nanocrystalline Composites

We have developed a novel processing technique to fabricate tungsten carbide (WC) nanocomposites with uniform grain size. In this method, pulsed laser deposition of WC in conjunction with a few monolayers of nickel aluminide (NiAl) is used to control the grain size of nanocrystalline composites. The grain size of WC was controlled by the thickness of tungsten carbide and the substrate temperature. The role of NiAl is to ensure the nucleation of tungsten carbide islands, and it is relatively insoluble in WC. Using this approach, we have fabricated nanocomposites of grain sizes ranging from 6 nm to 35 nm. The hardness of the composite increases with the decrease in grain size, following approximately Hall-Petch relationship. Below a critical value, we observed a softening behavior which has been modeled to be related to intragrain deformation or grain boundary shear. The role of NiAl in grain boundary deformation is of particular interest in strengthening and stabilizing against the grain growth of nanocrystalline composites. The new WC-NiAl composite is expected to have superior high-temperature strength compared to conventional microcrystalline WC-Co composites.