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Deliang Zhang - One of the best experts on this subject based on the ideXlab platform.
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a feasible ultrafine grained cu matrix composite microstructure for achieving high strength and high electrical conductivity
Journal of Alloys and Compounds, 2016Co-Authors: Dengshan Zhou, Wei Zeng, Deliang ZhangAbstract:Abstract An ultrafine grained Cu-5vol.%Al 2 O 3 composite with a microstructure consisting of bimodal Al 2 O 3 particles distributing at the boundaries of ultrafine Cu grains was fabricated by a combination of high energy mechanical milling and Powder Compact extrusion. The material showed a high tensile yield strength of 486 MPa and high electrical conductivity of 80% of the international annealed copper standard (IACS). Analysis of the findings shows that such microstructure can be further tailored to achieve high strength and high electrical conductivity with ultrafine grained or nanocrystalline Cu matrix composites.
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effects of holding time during pre sintering and post forging annealing on the microstructure and mechanical properties of ti parts fabricated by Powder Compact forging
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016Co-Authors: Mingtu Jia, Charlie Kong, Deliang Zhang, Jiamiao Liang, Brian GabbitasAbstract:Abstract Hydride-dehydride (HDH) Ti Powder was consolidated into fully dense parts of rocker arms for internal combustion engines by Powder Compact forging at 1350 °C. The microstructure, tensile mechanical properties and fracture behavior of forged Ti parts were studied. It was found that fully dense forged Ti parts had a fine α lamellar structure, and increasing the holding time of the Powder Compact at 1350 °C from zero to 5 min and post-forging annealing at 550 °C for 6 h are two effective ways to improve the level of consolidation of the Ti parts by removing weakly bonded interparticle boundaries (IPBs), leading to a significant increase of their ductility. The former approach is a better way of improving the level of consolidation due to the fact that it does not cause significant microstructure coarsening and clear decrease of tensile strength of the Ti parts. The correlation between the yield strength of the forged Ti parts without and with annealing and their average α-Ti lamellar thickness shows that it follows the Hall–Petch relationship, and the sensitivity of the yield strength of α-Ti to the average lamellar thickness is clearly higher than its sensitivity to the average size of equiaxed grains.
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microstructures and tensile mechanical properties of ti 6al 4v bar disk fabricated by Powder Compact extrusion forging
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: C Liang, M X, M T Jia, S Raynova, J Q Yan, Deliang ZhangAbstract:Ti–6Al–4V (wt%) bar and disk with a density close to 100%, a lamellar structure and oxygen content of 0.44 and 0.51 wt%, respectively, have been made by Powder Compact extrusion and Powder Compact forging of HDH Ti–6Al–4V Powder respectively. Their microstructure, tensile mechanical properties at different strain rates in the range of 10−4–10−1 s−1 and the fracture surfaces and longitudinal sections of the tensile test specimens have been studied. It was found that the level of consolidation of the PE/Ti–6Al–4V bar and PF/Ti–6Al–4V disk was very high, as reflected by their high strength and good ductility, small untransformed interparticle boundaries (smaller than 3 μm in sizes), and low volume fraction of cavities (<1.5%) formed by separation of Powder particles at the untransformed interparticle boundaries in the specimens tensile tested at a high strain rate of 10−2 s−1. The high level of consolidation achieved within a short time through induction heating and extrusion/forging of the Ti–6Al–4V Powder Compacts suggests that the rate of transforming interparticle boundaries to grain boundaries is very high, and the reasons for this might be formation of new Powder particle surfaces through plastic deformation and rapid dissolution of the Powder particle surface oxide films. The formation of cavities from the untransformed interparticle boundaries in the PE/Ti–6Al–4V bar and PF/Ti–6Al–4V disk is highly strain rate sensitive with the number and volume fraction of the cavities formed increases significantly with increasing the strain rate.
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synthesis of a tibw ti6al4v composite by Powder Compact extrusion using a blended Powder mixture
Journal of Alloys and Compounds, 2014Co-Authors: Deliang Zhang, Brian Gabbitas, Fei Yang, S MatthewsAbstract:Abstract A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by Powder Compact extrusion using a blended Powder mixture. The microstructural characterization of the various extruded samples showed that the different starting Powders, pre-alloyed Powder plus boron Powder or titanium plus Al–40V master alloy Powder plus boron Powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study.
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factors controlling the tensile properties of ultrafine structured cu 5vol al2o3 nanocomposite prepared by high energy mechanical milling and Powder Compact extrusion
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Dengshan Zhou, Charlie Kong, Deliang Zhang, Paul MunroeAbstract:Abstract The microstructures and tensile properties of two ultrafine structured Cu–5vol%Al2O3 nanocomposite samples made by a combination of high energy mechanical milling of a mixture of Cu Powder and gamma Al2O3 nanoPowder and Powder Compact extrusion were studied. The sample extruded at 750 °C exhibited a microstructure consisting of Cu grains with sizes in the range of 100–500 nm and a dispersion of Al2O3 nanoparticles with sizes in the range of 20–345 nm. With the extrusion temperature increasing to 900 °C, the Cu grain sizes remained almost unchanged, but a large fraction of the Al2O3 nanoparticles were dissolved, leading to possible formation of nanometer sized Al3+/O2− clusters. This microstructural difference of the two samples causes an interesting difference in tensile properties, with the sample extruded at 900 °C showing approximately 150 MPa higher yield strength and ultimate tensile strength and also better ductility than the sample extruded at 750 °C. It appears that this significant beneficial effect of dissolution of Al2O3 nanoparticles is mainly caused by the significant strengthening effect of the nanometer sized Al3+/O2− clusters through Orowan mechanism.
Rui Yang - One of the best experts on this subject based on the ideXlab platform.
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electron beam welding of a novel near α high temperature titanium alloy Powder Compact effect of post welding heat treatment on tensile properties
Journal of materials research and technology, 2021Co-Authors: Min Cheng, Ruipeng Guo, Xiaohui Shi, Junwei Qiao, Rui YangAbstract:Abstract A novel near α high temperature titanium alloy (Ti55) was produced from Powder Compact through hot isostatic pressing. Electron beam welding (EBW) was used to join the Ti55 alloy Powder Compact and effects of annealing treatment on the microstructure and mechanical properties of EBW joints were investigated. The residual stress distribution of as-welded joint was calculated using finite element method (FEM). The results show that the microstructure and microhardness profiles are non-uniform across the EBW joints. The tensile residual stresses are confirmed across the as-welded joints based on FEM analysis. All of tensile specimens failed at the base metal, indicating that the mechanical properties of EBW joints are equal to those of base metal, or better. The tensile strength of as-welded and as-annealed joints increases slightly compared with base metal. An obvious reduction on the reduction of area of EBW joints was obtained after annealing at 500 °C. Related mechanisms were discussed based on the residual stress, tensile deformation and the strain rate sensitivity.
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Effect of Powder Size on Fatigue Properties of Ti-6Al-4V Powder Compact Using Hot Isostatic Pressing
JOM, 2019Co-Authors: Ruipeng Guo, Bingbing Yu, Lei Xu, Xiaohui Shi, Rui YangAbstract:Ti-6Al-4V Powder Compacts were prepared using hot isostatic pressing (HIP), and the effect of Powder size on microstructure and fatigue properties of HIPed Powder Compacts was investigated. The results show that the microstructure of Powder Compacts is fine and homogeneous. The volume fraction of equiaxed α phase in the Powder Compact decreases with the increase of Powder size. The Powder Compact HIPed from Powder with a full size range (5–250 μ m) achieves excellent tensile properties and the best fatigue strength compared with the HIPed fine and coarse Powders. The relevant mechanisms are discussed based on the Powder surface quality and as-HIPed microstructure.
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microstructural evolution and mechanical properties of Powder metallurgy ti 6al 4v alloy based on heat response
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Ruipeng Guo, Rui Yang, Bernie Y. ZongAbstract:In present work, Powder metallurgy (PM) Ti-6Al-4V alloy was produced by hot isostatic pressing (HIPing) from gas atomized Powder. Various HIPing conditions and heat treatments were used to investigate the heat response of PM Ti-6Al-4V alloy. The results show that the optimization of HIPing parameters is temperature from 920 to 940 degrees C, pressure over 120 MPa and holding for 3 h. The microstructure of Powder Compact changes significantly after different heat treatments, while there was no obvious difference in tensile properties. Temperature induced porosity (TIP) in Powder Compact occurred after annealing at 930 degrees C for 1 h plus aging. The TIP has no obvious effects on tensile, impact, and fracture toughness properties of Powder Compact, but the TIP has an adverse effect on fatigue property, especially at shorter fatigue lives. In order to eliminate the TIP in Powder Compact, several probable solutions were suggested for the application of titanium Powder components. (C) 2015 Elsevier B.V. All rights reserved.
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influences of hot isostatic pressing temperature on microstructure tensile properties and tensile fracture mode of inconel 718 Powder Compact
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Litao Chang, Rui YangAbstract:Abstract Inconel 718 Powders have been hot-isostatic-pressed (HIPed) at representative temperatures to investigate the variations in microstructure, tensile properties and tensile fracture mode of the Powder Compact. Microstructure of the Powder Compacts were characterized by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The results showed that the interdendritic precipitates inherited from the Powders were partially retained in the Powder Compacts when the Powders were HIPed at or below 1210 °C but were eliminated when HIPed at and above 1260 °C. The grain size uniformity of the Powder Compacts first increases and then decreases with increasing HIPing temperature. Prior particle boundaries (PPBs) were observed in the Powder Compacts HIPed at and below 1260 °C but was eliminated when HIPed at 1275 °C. The PPBs were decorated with carbide particles, the amount of the carbide particles at the PPBs decreases with increasing HIPing temperature. Most of the PPBs were pinned by the carbide particles in the Compacts HIPed at 1140 °C. When the HIPing temperature was increased to 1210 °C and 1260 °C, a large number of PPBs de-pinned and moved beyond the pinning carbide particles, leading to grain growth and leaving carbide particles at the site of the original PPBs within the new grains. With increasing HIPing temperature, the 0.2% yield strength of the Powder Compacts at 650 °C decreases, the tensile elongation increases, and the tensile fracture mode changed from inter-particle dominant fracture to fully dimple ductile fracture.
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effect of heat treatment on microstructure and mechanical properties of the hot isostatic pressed inconel 718 Powder Compact
Journal of Alloys and Compounds, 2014Co-Authors: Litao Chang, Faqiang Zhang, Rui YangAbstract:Abstract The present study deals with the optimization of the mechanical properties of the hot-isostatic-pressed Inconel 718 Powder Compact. Several heat treatments, including the solution plus aging with different solution temperature and the direct aging scheme, have been designed based on the phase relations of Inconel 718 and been employed for the optimization. The results indicate that the direct aging heat treatment is the best one, because it ensures a good balance of the strength and ductility of the Powder Compact. The tensile and stress rupture properties of the direct aged alloy have all met the specifications for Inconel 718. Solution process leads to a decrease of grain boundary strength and poor ductility because of the precipitation of carbide and δ phase at the prior particle boundaries or formation of thermal induced porosities at the triple junctions, and is then not appropriate for the Powder Compact. Yield strength of the direct aged alloy is a little lower than the solution treated alloy because of over aging of the γ′′ precipitates.
Brian Gabbitas - One of the best experts on this subject based on the ideXlab platform.
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solution treatment of ti 6al 4v alloy produced by consolidating blended Powder mixture using a Powder Compact extrusion route
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Ajit Pal Singh, Rob Torrens, Fei Yang, Brian GabbitasAbstract:Abstract Titanium alloys are very sensitive to thermal history and different microstructures are obtained depending on their chemistry, processing route and post-processing heat treatment. The objective of this paper is to characterise solution-treated Ti-6Al-4V alloy rods from microstructural investigations using optical and transmission electron microscopy (TEM) in addition to measurements of chemical composition and levels of impurity oxygen. From the results, it is clear that the compositions and oxygen concentration of the different rods, which varied between 0.34–0.36 wt%, was consistent from one extrusion to another. TEM analysis of the as-extruded material with a fine lamellar microstructure indicates that the severe deformation and attendant dynamic recrystallization during and after hot extrusion did not give rise to any undesirable features that can degrade the ductility. Solution treatment above the β transus and subsequent ageing causes grain growth with grains containing a metastable martensitic structure (only α’ phase was present), some retained β and a limited formation of acicular secondary α. The α+β quenched and aged treatment gives a lamellar type morphology, but at the α interfaces there is retained β with some secondary α and potentially some α’ phase. In terms of mechanical behaviour, the data from v-notch Charpy impact tests and non-standard micro-tensile testing suggests that both water quenched and aged microstructures give a higher yield strength (~1022–1033 MPa) and micro-hardness (388 HV), while the fracture-related properties such as estimated plastic strain and impact toughness were between 5–6% and 13.7 J respectively. Overall, the level of mechanical properties reported here is better than that for typical values reported in the literature for as-cast material after similar solution treatments.
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feasibility of producing ti 6al 4v alloy for engineering application by Powder Compact extrusion of blended elemental Powder mixtures
Journal of Alloys and Compounds, 2017Co-Authors: Fei Yang, Brian GabbitasAbstract:Abstract In this paper, two different Powder Compact extrusion processes were explored to rapidly produce Ti-6Al-4V alloys from the Powder mixture of hydride-dehydride titanium Powder, Al-V master alloy Powder and elemental Al Powder. The mechanical properties of the as-extruded Ti-6Al-4V alloys could achieve the yield strength of 1180–1200 MPa, the ultimate strength of 1215–1272 MPa and an elongation to fracture of about 10%, which could meet the requirements of most engineering applications.
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effects of holding time during pre sintering and post forging annealing on the microstructure and mechanical properties of ti parts fabricated by Powder Compact forging
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016Co-Authors: Mingtu Jia, Charlie Kong, Deliang Zhang, Jiamiao Liang, Brian GabbitasAbstract:Abstract Hydride-dehydride (HDH) Ti Powder was consolidated into fully dense parts of rocker arms for internal combustion engines by Powder Compact forging at 1350 °C. The microstructure, tensile mechanical properties and fracture behavior of forged Ti parts were studied. It was found that fully dense forged Ti parts had a fine α lamellar structure, and increasing the holding time of the Powder Compact at 1350 °C from zero to 5 min and post-forging annealing at 550 °C for 6 h are two effective ways to improve the level of consolidation of the Ti parts by removing weakly bonded interparticle boundaries (IPBs), leading to a significant increase of their ductility. The former approach is a better way of improving the level of consolidation due to the fact that it does not cause significant microstructure coarsening and clear decrease of tensile strength of the Ti parts. The correlation between the yield strength of the forged Ti parts without and with annealing and their average α-Ti lamellar thickness shows that it follows the Hall–Petch relationship, and the sensitivity of the yield strength of α-Ti to the average lamellar thickness is clearly higher than its sensitivity to the average size of equiaxed grains.
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synthesis of a tibw ti6al4v composite by Powder Compact extrusion using a blended Powder mixture
Journal of Alloys and Compounds, 2014Co-Authors: Deliang Zhang, Brian Gabbitas, Fei Yang, S MatthewsAbstract:Abstract A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by Powder Compact extrusion using a blended Powder mixture. The microstructural characterization of the various extruded samples showed that the different starting Powders, pre-alloyed Powder plus boron Powder or titanium plus Al–40V master alloy Powder plus boron Powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study.
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Consolidation of Titanium, and Ti-6Al-4V Alloy Powders by Powder Compact Forging
Materials Science Forum, 2009Co-Authors: Deliang Zhang, Brian Gabbitas, Stiliana Rousseva Raynova, Vijay Navaratna Nadakuduru, Barry RobinsonAbstract:Consolidation of titanium and titanium alloy Powders using thermomechanical Powder metallurgy (TPM) processes (Powder Compact forging, extrusion and rolling) is one way that can lead to cost-effective production of high value-added consolidated titanium and titanium alloy products such as near-net shaped components, tubes and plates. This paper provides an overview of the quality, microstructure (to limited depth), porosity level and mechanical properties of disks produced using open die forging of Powder Compacts of CP titanium and Ti-6Al-4V alloy Powders. The general materials science principles underlying the relationships between processing conditions, microstructure and the mechanical properties of the disks made by using the Powder Compact forging are discussed.
Dengshan Zhou - One of the best experts on this subject based on the ideXlab platform.
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effect of extrusion temperature on microstructure and properties of an ultrafine grained cu matrix nanocomposite fabricated by Powder Compact extrusion
Journal of Materials Science, 2018Co-Authors: Dengshan Zhou, Hongwei Geng, Wei Zeng, Gang Sha, Charlie Kong, Zakaria Quadir, Paul Munroe, Rob Torrens, Patrick TrimbyAbstract:Ultrafine-grained Cu–5 vol%Al2O3 nanocomposite rods were fabricated by a combination of high-energy mechanical milling of Cu and Al2O3 Powders and Powder Compact extrusion at 300, 500, 700 and 900 °C. The extruded rods were investigated to evaluate microstructures, mechanical properties, fracture behavior and electrical resistivity. It was found that the extrusion temperature has a pronounced effect on Cu grain growth, Al2O3 particle coarsening and particle distribution. High-temperature extrusion leads to directional coarsening of certain grains. As such, a heterogeneous matrix structure of large elongated and equiaxed grains is created, and this unique matrix structure brings beneficial effects in tensile ductility and electrical resistivity. While Al2O3 dispersions in the matrix improve the overall performance of the nanocomposite, an incorrect selection of the extrusion temperature may have detrimental effects on yield strength and resistivity. Tensile fractography investigation shows that the presence of Al2O3 results in failures along grain boundaries. This study also provides a framework for modeling the mechanical and electrical properties of such complex matrix structures. Modeling tools/formulae can be used to predict mechanical/electrical properties via microscopic characteristics and hence can also be used to understand the effect of processing variables.
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a feasible ultrafine grained cu matrix composite microstructure for achieving high strength and high electrical conductivity
Journal of Alloys and Compounds, 2016Co-Authors: Dengshan Zhou, Wei Zeng, Deliang ZhangAbstract:Abstract An ultrafine grained Cu-5vol.%Al 2 O 3 composite with a microstructure consisting of bimodal Al 2 O 3 particles distributing at the boundaries of ultrafine Cu grains was fabricated by a combination of high energy mechanical milling and Powder Compact extrusion. The material showed a high tensile yield strength of 486 MPa and high electrical conductivity of 80% of the international annealed copper standard (IACS). Analysis of the findings shows that such microstructure can be further tailored to achieve high strength and high electrical conductivity with ultrafine grained or nanocrystalline Cu matrix composites.
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factors controlling the tensile properties of ultrafine structured cu 5vol al2o3 nanocomposite prepared by high energy mechanical milling and Powder Compact extrusion
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Dengshan Zhou, Charlie Kong, Deliang Zhang, Paul MunroeAbstract:Abstract The microstructures and tensile properties of two ultrafine structured Cu–5vol%Al2O3 nanocomposite samples made by a combination of high energy mechanical milling of a mixture of Cu Powder and gamma Al2O3 nanoPowder and Powder Compact extrusion were studied. The sample extruded at 750 °C exhibited a microstructure consisting of Cu grains with sizes in the range of 100–500 nm and a dispersion of Al2O3 nanoparticles with sizes in the range of 20–345 nm. With the extrusion temperature increasing to 900 °C, the Cu grain sizes remained almost unchanged, but a large fraction of the Al2O3 nanoparticles were dissolved, leading to possible formation of nanometer sized Al3+/O2− clusters. This microstructural difference of the two samples causes an interesting difference in tensile properties, with the sample extruded at 900 °C showing approximately 150 MPa higher yield strength and ultimate tensile strength and also better ductility than the sample extruded at 750 °C. It appears that this significant beneficial effect of dissolution of Al2O3 nanoparticles is mainly caused by the significant strengthening effect of the nanometer sized Al3+/O2− clusters through Orowan mechanism.
J M F Ferreira - One of the best experts on this subject based on the ideXlab platform.
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manufacturing and bending behaviour of in situ foam filled aluminium alloy tubes
Materials & Design, 2015Co-Authors: Isabel Duarte, Matej Vesenjak, Lovre Krstulovicopara, Ivan Anžel, J M F FerreiraAbstract:The manuscript focuses on manufacturing of new in situ foam-filled tubes (in situ FFTs) of Al-alloys including the foaming stage and studying their mechanical behaviour under quasi-static and dynamic bending loadings. The composite structures were manufactured by the Powder Compact foaming technique. These structures are fabricated by heating foamable precursor material pieces above their solid temperature inside thin-walled tubes. Different manufacturing parameters were appropriately adjusted based on preliminary experiments. The mechanical crushing behaviour and failure mechanisms were assessed by three-point bending experiments supported by infrared thermography. The bending performance of in situ FFTs and ex situ foam-filled heat treated tubes (ex situ FFTTs) were compared with that of empty tubes subjected to heat treatment. The observed results have been explained in terms of the structural changes in the thermally treated tubes, the surface roughness derived from oxidation, and the dimensions of the interface gap between the two components in the composite structures. The in situ FFTs composite structures confirmed stable and controllable deformation and a promising energy absorption capability.
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sintering and devitrification of glass Powder Compacts in the akermanite gehlenite system
Journal of Materials Science, 2013Co-Authors: Allu Amarnath Reddy, Dilshat U Tulyaganov, Ashutosh Goel, Saurabh Kapoor, M J Pascual, J M F FerreiraAbstract:The sintering and devitrification behavior of glass-Powder Compacts with four compositions, Ca2Mg0.5Al1.0Si1.5O7, Ca2Mg0.6Al0.8Si1.6O7, Ca2Mg0.7Al0.6Si1.7O7, and Ca2Mg0.8Al0.4Si1.8O7, corresponding to akermanite–gehlenite ratios (mol%) of 50/50, 60/40, 70/30, and 80/20 were investigated. Glass frits were prepared by the classical melt quenching technique in water. The structure of the glasses was investigated using FTIR and NMR, whereas the sintering behavior was studied by DTA and HSM. Sintering precedes crystallization only in Ca2Mg0.5Al1.0Si1.5O7 glass while in the remaining glass compositions maximum densification was achieved slight after the onset of crystallization. However, the ratios of final area/initial area (A/A0) of the glass-Powder Compact ranging from 0.63 to 0.66 imply towards good densification levels (95–98 %) achieved in the investigated glasses. Qualitative and quantitative XRD analyzes were performed in glass-Powder Compacts heat treated at 900 and 1000 °C. Merwinite was found to crystallize first followed by decomposition at higher temperatures to form akermanite-like phase.