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Full-Text Articles in Social and Behavioral Sciences
Response Of The Al Σ5 〈001〉 Left {310} Symmetric Tilt Grain Boundary To The Shear Deformation Simulated By Molecular Dynamics, Kuiyu Cheng, Cheng Lu, A Kiet Tieu
Response Of The Al Σ5 〈001〉 Left {310} Symmetric Tilt Grain Boundary To The Shear Deformation Simulated By Molecular Dynamics, Kuiyu Cheng, Cheng Lu, A Kiet Tieu
Faculty of Engineering and Information Sciences - Papers: Part A
In the present study, shear response of the Al [001] symmetrical tilting Σ5 (310) grain boundary (GB) was investigated by a three dimensional bicrystal at 500~750 K. It was found that the GB gradually rotated around the [001] tilt axis during the shear deformation due to the combination of surface strain, GB sliding and GB coupled motion. These rotated grain boundaries were Σ5 asymmetrical or symmetrical tilt grain boundaries and led to the normal stress σxx in the bicrystal system. It was also found that the response of the grain boundary to the shear deformation was closely related to the …
Vacancy-Type Defects Study On Ultra-Fine Grained Aluminium Processed By Severe Plastic Deformation, Li-Jun Su, C Lu, Guanyu Deng, A Kiet Tieu, L C. Zhang, P Guagliardo, S N. Samarin, J F. Williams
Vacancy-Type Defects Study On Ultra-Fine Grained Aluminium Processed By Severe Plastic Deformation, Li-Jun Su, C Lu, Guanyu Deng, A Kiet Tieu, L C. Zhang, P Guagliardo, S N. Samarin, J F. Williams
Faculty of Engineering and Information Sciences - Papers: Part A
Vacancy-type defects play an important role in the metal materials deformed by severe plastic deformation (SPD). The present work use positron annihilation lifetime spectroscopy (PALS) to test the vacancy-type defects in aluminium alloys processed by equal channel angular pressing (ECAP) and accumulative roll bonding (ARB). ECAP at room temperature and cryogenic temperature was conducted to AA1050 and ARB with 200 C preheating was conducted to AA1050 and AA6061 to produce laminated AA1050 sheets, AA6061 sheets and AA1050/AA6061 composites. High fraction of vacancy-type defects were detected in all the deformed samples. Vacancies associated with dislocations and bulk mono-vacancies have been identified …
Deformation Characterization Of Micro Rolling For Stainless Steel Foil, Haibo Xie, Kenichi Manabe, Tsuyoshi Furushima, Kazuo Tada, Zhengyi Jiang
Deformation Characterization Of Micro Rolling For Stainless Steel Foil, Haibo Xie, Kenichi Manabe, Tsuyoshi Furushima, Kazuo Tada, Zhengyi Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
Physical parameters such as microscopic roughness become very important in micro forming process due to increasing surface to volume ratio. As a very important phenomenon in metal forming process, friction size effects are becoming more attracting for researchers because traditional models are not reliable. In this study, the micro rolling deformation characterization has been investigated with SUS 304 stainless steel considering the effect of lubricant, and there exists a sticking area in the contact zone. The evolution of surface roughness and oil film thickness are analyzed. The foil thickness plays an important role in the tribological features of rolling. All …
Molecular Dynamics Simulation On Σ5 Grain Boundaries Of Copper Bicrystal Under Tensile And Shear Deformation, Liang Zhang, Cheng Lu, A Kiet Tieu
Molecular Dynamics Simulation On Σ5 Grain Boundaries Of Copper Bicrystal Under Tensile And Shear Deformation, Liang Zhang, Cheng Lu, A Kiet Tieu
Faculty of Engineering and Information Sciences - Papers: Part A
Molecular Dynamics simulation are employed to investigate the structures and mechanical behavior of both symmetric and asymmetric Σ5[0 0 1] tilt grain boundaries (GBs) of copper bicrystal under uniaxial tension and shear deformation. Simulation results indicate that the Σ5 asymmetric GBs can facet into their corresponding symmetric GB structures. The maximum tensile stress of symmetric GBs is higher than the asymmetric ones at both 10 K and 300 K, which suggests the symmetric GBs may have a more stable boundary structures. All the Σ5 GBs investigate in this study can migrate under the shear deformation with different velocity. The migration …
The Formation Of Complex Microstructures After Different Deformation Modes In Advanced High-Strength Steels, Ilana Timokhina, Elena V. Pereloma, Peter Hodgson
The Formation Of Complex Microstructures After Different Deformation Modes In Advanced High-Strength Steels, Ilana Timokhina, Elena V. Pereloma, Peter Hodgson
Faculty of Engineering and Information Sciences - Papers: Part A
The microstructure of transformation induced plasticity (TRIP) and dual phase (DP) multiphase steels after stamping of an industrial component at different strain levels was investigated using transmission electron microscopy. The TRIP steel microstructure showed a more complex dislocation substructure of ferrite at different strain levels than DP steel. The deformation microstructure of the stamped parts was compared to the deformation microstructure in these complex steels for different "equivalent" tensile strains. It was found that the microstructures are similar only at high levels of strain (>10 pct) for both steels.
Analysis Of Internal Crack Healing Mechanism Under Rolling Deformation, Haitao Gao, Zhengrong Ai, Hailiang Yu, Hongyan Wu, Xianghua Liu
Analysis Of Internal Crack Healing Mechanism Under Rolling Deformation, Haitao Gao, Zhengrong Ai, Hailiang Yu, Hongyan Wu, Xianghua Liu
Faculty of Engineering and Information Sciences - Papers: Part A
A new experimental method, called the 'hole filling method', is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing mechanism. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic deformation, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic deformation followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from …
A Study Of Plastic Deformation Behavior During High Pressure Torsion Process By Crystal Plasticity Finite Element Simulation, Peitang Wei, Cheng Lu, A K. Tieu, Guanyu Deng
A Study Of Plastic Deformation Behavior During High Pressure Torsion Process By Crystal Plasticity Finite Element Simulation, Peitang Wei, Cheng Lu, A K. Tieu, Guanyu Deng
Faculty of Engineering and Information Sciences - Papers: Part A
High pressure torsion (HPT) is an efficient technique of producing ultrafine grained materials with exceptional small grain size. In this study, a crystal plasticity finite element method (CPFEM) model has been developed to investigate the plastic deformation behavior of pure aluminum single crystal during the HPT process. The simulation results show that, the distribution and evolution of the macroscopic plastic strain and the accumulative shear strain are similar. The value increases with the increase of the distance from the center as well as the number of revolution. The simulation is capable of reflecting the anisotropic characteristics of HPT deformation, a …
Constitutive Analysis For Hot Deformation Behaviour Of Novel Bimetal Consisting Of Pearlitic Steel And Low Carbon Steel, Xingjian Gao, Zhengyi Jiang, Dongbin Wei, Huijun Li, Sihai Jiao, Jianzhong Xu, Xiaoming Zhang, Jingtao Han, Dengfu Chen
Constitutive Analysis For Hot Deformation Behaviour Of Novel Bimetal Consisting Of Pearlitic Steel And Low Carbon Steel, Xingjian Gao, Zhengyi Jiang, Dongbin Wei, Huijun Li, Sihai Jiao, Jianzhong Xu, Xiaoming Zhang, Jingtao Han, Dengfu Chen
Faculty of Engineering and Information Sciences - Papers: Part A
To understand the high temperature flow behaviour of a novel pearlitic steel (PS) and low carbon steel (LCS) bimetal, hot compression tests in a wide range of temperature and strain rate were conducted on a Gleeble 3500 thermo mechanical simulator, and the constitutive model was developed based on the experimental data. The measured true stress-strain curves exhibited three types of variation patterns, which are (i) a plateau type, (ii) single peak type and (iii) multi peaks type. These patterns well displayed the effects of the deformation temperature, strain rate and plastic strain on the flow behaviour of the bimetal. By …
Crack Healing In A Low-Carbon Steel Under Hot Plastic Deformation, Hailiang Yu, Xianghua Liu, Xinwen Li, Ajit R. Godbole
Crack Healing In A Low-Carbon Steel Under Hot Plastic Deformation, Hailiang Yu, Xianghua Liu, Xinwen Li, Ajit R. Godbole
Faculty of Engineering and Information Sciences - Papers: Part A
The behavior of internal crack healing in low-carbon steel samples undergoing hot plastic deformation was investigated using the MMS 200 thermo-mechanical simulator. The characterization of cracks after plastic deformation was analyzed using scanning electron microscopy under different heating temperatures, reduction ratios, numbers of deformation passes, strain rates, and holding time durations. It was found that the degree of crack healing increases with increasing heating temperature, reduction ratio, and holding time duration, and with decreasing number of deformation passes and strain rate.
Atomistic Simulation Of Tensile Deformation Behavior Of Σ5 Tilt Grain Boundaries In Copper Bicrystal, Liang Zhang, Cheng Lu, A Kiet Tieu
Atomistic Simulation Of Tensile Deformation Behavior Of Σ5 Tilt Grain Boundaries In Copper Bicrystal, Liang Zhang, Cheng Lu, A Kiet Tieu
Faculty of Engineering and Information Sciences - Papers: Part A
Experiments on polycrystalline metallic samples have indicated that Grain boundary (GB) structure can affect many material properties related to fracture and plasticity. In this study, atomistic simulations are employed to investigate the structures and mechanical behavior of both symmetric and asymmetric ∑5[0 0 1] tilt GBs of copper bicrystal. First, the equilibrium GB structures are generated by molecular statics simulation at 0K. The results show that the ∑5 asymmetric GBs with different inclination angles (φ) are composed of only two structural units corresponding to the two ∑5 symmetric GBs. Molecular dynamics simulations are then conducted to investigate the mechanical response …
Effects Of Hydrogen On The Critical Conditions For Dynamic Recrystallization Of Titanium Alloy During Hot Deformation, Jingwei Zhao, Hua Ding, Zhengyi Jiang, Dongbin Wei, Kezhi Linghu
Effects Of Hydrogen On The Critical Conditions For Dynamic Recrystallization Of Titanium Alloy During Hot Deformation, Jingwei Zhao, Hua Ding, Zhengyi Jiang, Dongbin Wei, Kezhi Linghu
Faculty of Engineering and Information Sciences - Papers: Part A
Hot deformation tests were performed to study the flow behavior and microstructural evolution of a Ti600 titanium alloy with different hydrogen contents. The effects of hydrogen on the critical conditions for the initiation of dynamic recrystallization (DRX) were investigated. The DRX kinetics models of hydrogenated Ti600 alloy were developed, and the DRX volume fractions were quantified under different deformation conditions. The results indicate that the addition of proper hydrogen (no greater than 0.3 pct) benefits the decrease of both the critical stress and critical strain for the initiation of DRX. The critical stress and critical strain are dependent linearly on …
Cellular Automaton Simulation Of Hot Deformation Of Trip Steel, Ying Zhi, Xianghua Liu, Hailiang Yu
Cellular Automaton Simulation Of Hot Deformation Of Trip Steel, Ying Zhi, Xianghua Liu, Hailiang Yu
Faculty of Engineering and Information Sciences - Papers: Part A
The recrystallization process of hot deformed austenite of TRIP steel was predicted using Cellular Automaton (CA) combined with the principles of physical metallurgy. A model was developed for prediction of the dynamic and static recrystallization microstructure evolution and properties of hot deformed austenite for TRIP steel. The theoretical modeling of recrystallization was based on dislocation density. The microstructure evolution of austenite recrystallization of TRIP steel (such as the grain shape and size, volume fraction, kinetics curve of recrystallization) was predicted both visually and quantitatively. The distribution and variation of the dislocation density and flow stress were also obtained, and the …
An Experimental Investigation On The Deformation And Degradation Behaviour Of Geogrid-Reinforced Ballast, Sd. K Karimullah Hussaini, B Indraratna, J S. Vinod
An Experimental Investigation On The Deformation And Degradation Behaviour Of Geogrid-Reinforced Ballast, Sd. K Karimullah Hussaini, B Indraratna, J S. Vinod
Faculty of Engineering and Information Sciences - Papers: Part A
Railroad ballast, owing to its unbounded granular nature, spreads laterally when subjected to large vertical axle loads, which influences the track stability. In this view, large-scale cyclic tests have been conducted on ballast to explore the role of geogrid in controlling the lateral deformation of ballast and hence improving the track performance. Fresh latite ballast having a mean particle size of 35 mm and geogrids with different aperture sizes was used for the investigations. Tests were conducted using a modified process simulation test (MPST) apparatus at a loading frequency of 20 Hz, with geogrid placed at the subballast-ballast interface and …
A Deformation Mechanism Of Hard Metal Surrounded By Soft Metal During Roll Forming, Hailiang Yu, A Kiet Tieu, Cheng Lu, Xiong Liu, Ajit Godbole, Huijun Li, Charlie Kong, Q Qin
A Deformation Mechanism Of Hard Metal Surrounded By Soft Metal During Roll Forming, Hailiang Yu, A Kiet Tieu, Cheng Lu, Xiong Liu, Ajit Godbole, Huijun Li, Charlie Kong, Q Qin
Faculty of Engineering and Information Sciences - Papers: Part A
It is interesting to imagine what would happen when a mixture of soft-boiled eggs and stones is deformed together. A foil made of pure Ti is stronger than that made of Cu. When a composite Cu/Ti foil deforms, the harder Ti will penetrate into the softer Cu in the convex shapes according to previously reported results. In this paper, we describe the fabrication of multilayer Cu/Ti foils by the roll bonding technique and report our observations. The experimental results lead us to propose a new deformation mechanism for a hard metal surrounded by a soft metal during rolling of a …
Effect Of Austenite Deformation Temperature On Nb Clustering And Precipitation In Microalloyed Steel, E V Pereloma, A G Kostryzhev, A Alshahrani, C Zhu, J M. Cairney, C R. Killmore, S P. Ringer
Effect Of Austenite Deformation Temperature On Nb Clustering And Precipitation In Microalloyed Steel, E V Pereloma, A G Kostryzhev, A Alshahrani, C Zhu, J M. Cairney, C R. Killmore, S P. Ringer
Faculty of Engineering and Information Sciences - Papers: Part A
The effect of thermomechanical processing conditions on Nb clustering and precipitation in both austenite and ferrite in a Nb-Ti microalloyed steel was studied using electron microscopy and atom probe tomography. A decrease in the deformation temperature increased the Nb-rich precipitation in austenite and decreased the extent of precipitation in ferrite. Microstructural mechanisms that explain this variation are discussed. 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Methods Of Vacuum Consolidation And Their Deformation Analyses, Jin-Chun Chai, John Philip Carter, M D. Liu
Methods Of Vacuum Consolidation And Their Deformation Analyses, Jin-Chun Chai, John Philip Carter, M D. Liu
Faculty of Engineering and Information Sciences - Papers: Part A
Two methods, namely the air-tight sheet method and the vacuum-drain method (sheetless), are generally used to conduct vacuum consolidation in the field. The advantages and disadvantages of both methods and the techniques for preventing vacuum leakage through a middle sand layer in a deposit, as well as the method for maintaining vacuum pressure when large settlement occurs, have been described. Vacuum pressure is an isotropic consolidation pressure applied to a soil deposit, and the deformation induced is different from that induced by a surcharge (e.g. the weight of an embankment). Two typical case histories in Japan are presented and deformation …
Effect Of Directional Solidification Rate On The Microstructure And Properties Of Deformation-Processed Cu-7cr-0.1ag In Situ Composites, Keming Liu, Zhengyi Jiang, Jingwei Zhao, Jin Zou, Zhibao Chen, Deping Lu
Effect Of Directional Solidification Rate On The Microstructure And Properties Of Deformation-Processed Cu-7cr-0.1ag In Situ Composites, Keming Liu, Zhengyi Jiang, Jingwei Zhao, Jin Zou, Zhibao Chen, Deping Lu
Faculty of Engineering and Information Sciences - Papers: Part A
The influence of directional solidification rate on the microstructure, mechanical properties and conductivity of deformation-processed Cu-7Cr-0.1Ag in situ composites produced by thermo-mechanical processing was systematically investigated. The microstructure was analyzed by optical microscopy and scanning electronic microscopy. The mechanical properties and conductivity were evaluated by tensile-testing machine and micro-ohmmeter, respectively. The results indicate that the size, shape and distribution of second-phase Cr grains are significantly different in the Cu-7Cr-0.1Ag alloys with different growth rates. At a growth rate of 200 μm s-1, the Cr grains transform into fine Cr fiber-like grains parallel to the pulling direction from the Cr dendrites. …
Closure To "Deformation Of Coal Fouled Ballast Stabilized With Geogrid Under Cyclic Load" By Buddhima Indraratna, Ngoc Trung Ngo, And Cholachat Rujikiatkamjorn, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn
Closure To "Deformation Of Coal Fouled Ballast Stabilized With Geogrid Under Cyclic Load" By Buddhima Indraratna, Ngoc Trung Ngo, And Cholachat Rujikiatkamjorn, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn
Faculty of Engineering and Information Sciences - Papers: Part A
The writers highly appreciate the keen feedback provided by the discusser and also for raising some other important aspects of the experimental program. While the writers are in general agreement with the discusser’s comments, some points warrant further clarification.