Grain Boundary Deformation and Fracture of a Fine Grained, High Purity Al-2% Mg Alloy at 150° C (423K)

While WC-Co based alloys are extensively used in industry, there is still uncertainty as to the microscopic mechanisms that control deformation and fracture in the hard carbide phase. In this paper, observations are reported of intergranular cracking between WC grains in a fine-grained WC-Co composite. The onset of cracking is related to the operative slip systems in neighbouring grains, the grain boundary plane and the relative orientation of the two grains. Bright field imaging and micro-diffraction are used to determine these parameters.

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Developing a low-alloyed fine-grained Mg alloy with high strength-ductility based on dislocation evolution and grain boundary segregation

Scripta Materialia ◽

10.1016/j.scriptamat.2021.114414 ◽

2022 ◽

Vol 209 ◽

pp. 114414

Author(s):

Zhi Zhang ◽

Jinghuai Zhang ◽

Jinshu Xie ◽

Shujuan Liu ◽

Yuying He ◽

...

Keyword(s):

Grain Boundary ◽

Boundary Segregation ◽

High Strength ◽

Grain Boundary Segregation ◽

Mg Alloy ◽

Fine Grained

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Deformation Behavior of Fine Grained Al-Mg Alloy under Biaxial Stress

Materials Science Forum ◽

10.4028/www.scientific.net/msf.503-504.475 ◽

2006 ◽

Vol 503-504 ◽

pp. 475-480 ◽

Cited By ~ 5

Author(s):

Masafumi Noda ◽

Kunio Funami

Keyword(s):

Grain Boundary ◽

Tensile Deformation ◽

Grain Boundary Sliding ◽

Biaxial Stress ◽

Mg Alloy ◽

Strain Rates ◽

Fine Grained ◽

Biaxial Tensile ◽

Wide Range ◽

Boundary Sliding

The grain boundary sliding and the formation of slipped bands and cavitations during biaxial tensile deformation were examined in fine grained Al-Mg alloy. Biaxial tensile testing was conducted with cruciform specimens at initial strain rates of 10-4 to 101s-1. It was found that at the same equivalent strain conditions, the number of cavities under biaxial tension is significantly greater than that under uniaxial tension. A greater prevalence of slipped bands and grain separations were clearly observed under biaxial stress than under uniaxial stress. It was suggested that development of slipped bands resulted from the formation of elongated cavities and multiple deformed bands under biaxial stress. Additionally, the m-value under biaxial stress remained at about 0.3 over a wide range of strain rates. The effects of grain separation and formation of cavities were related to the motion of grain boundary sliding, grain size and loading conditions.

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Grain Boundary Deformation and Fracture Mechanisms in Dwell Fatigue Crack Growth in Turbine Disk Superalloy ME3

Superalloys 2012 ◽

10.1002/9781118516430.ch17 ◽

2012 ◽

pp. 149-158

Author(s):

Jinesh Dahal ◽

Kimberly Maciejewski ◽

Hamouda Ghonem

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Grain Boundary ◽

Crack Growth ◽

Turbine Disk ◽

Fracture Mechanisms ◽

Dwell Fatigue ◽

Deformation And Fracture ◽

Boundary Deformation

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Microstructural Evolution of High Purity Al-Cu-Mg Alloy during Homogenization

Materials Science Forum ◽

10.4028/www.scientific.net/msf.788.208 ◽

2014 ◽

Vol 788 ◽

pp. 208-214 ◽

Cited By ~ 1

Author(s):

Hui Zhong Li ◽

Yang Jie Ou ◽

Hui Juan Liao ◽

Xiao Peng Liang ◽

Jun Jiang

Keyword(s):

Grain Boundary ◽

High Purity ◽

Optimum Parameter ◽

Energy Dispersive Spectrometry ◽

Phase Evolution ◽

Mg Alloy ◽

Dendritic Segregation ◽

Composition Distribution ◽

The Matrix ◽

Increasing Temperature

The microstructure, composition distribution and phase evolution of a high-purity Al-Cu-Mg alloy under homogenization were investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and differential scanning calorimeter (DSC). The results show that severe dendritic segregation exists in Al-Cu-Mg alloy ingot. There are a lot of eutectic phases at grain boundary and the primary phases at grain boundary are Al2Cu and Al2CuMg. The primary phases dissolve into the matrix gradually during homogenization with increasing temperature and holding time, which can be described by a constitutive equation in exponential function. The optimum parameter of homogenization is 500°C for 18 h, which is consistent with the result of homogenization kinetic analysis.

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Creep behavior of a cryomilled ultrafine-grained Al–4% Mg alloy

Journal of Materials Research ◽

10.1557/jmr.2000.0318 ◽

2000 ◽

Vol 15 (10) ◽

pp. 2215-2222 ◽

Cited By ~ 20

Author(s):

R. W. Hayes ◽

V. Tellkamp ◽

E. J. Lavernia

Keyword(s):

Activation Energy ◽

Thermal Stability ◽

Grain Size ◽

Grain Boundary ◽

Creep Behavior ◽

Boundary Region ◽

Mg Alloy ◽

Pinning Force ◽

Ultrafine Grained ◽

Boundary Deformation

The creep behavior of a cryomilled ultrafine-grained Al–Mg alloy was examined. The grain size ranged from 300 to 400 nm. The stress exponents ranged from 7.2 to 7.4. The apparent activation energy for creep, 83.7 kJ/mol at 27.5 MPa and 77 kJ/mol at 38 MPa, agreed well with the activation energy for grain boundary diffusion in aluminum. Transmission electron microscope analysis following creep at 300 °C to approximately 0.2% strain in 1411 h revealed the grain size was unchanged from its as-extruded size indicating significant thermal stability of this material at relatively high fractions of the melting temperature. The creep resistance of the Al–Mg alloy was rationalized in terms of an attractive interaction between grain boundary dislocations and incoherent particles within the boundary region, which suppressed grain boundary deformation. The grain boundary particles also led to high thermal stability by exerting a Zener pinning force on the grain boundaries, thus inhibiting grain growth at high temperatures.

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