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Kevin P. Plucknett - One of the best experts on this subject based on the ideXlab platform.
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reciprocating wear behaviour of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC based cermets have been prepared with three different grades of stainless steel binder (304L, 316L and 410L). The cermets were densified by vacuum melt infiltration, at 1500 °C, which allows the steel binder content to be readily varied from 5 to 30 vol%. The cermets were assessed for their hardness and indentation fracture resistance using Vickers testing. The reciprocating wear response was evaluated using a ball on Flat Geometry, with a WC-Co counter face sphere. It was shown that the coefficient of friction increases with increasing steel binder content, and also with increasing load and wear time. Similarly, the specific wear rate increases with both steel binder content and applied load, but was largely independent of the steel grade used.
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microstructural damage following reciprocating wear of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract High density TiC-based cermets were fabricated using a simple melt-infiltration/sintering method, with three different grades of stainless steel binder. Reciprocating wear tests were conducted using a ball-on-Flat Geometry, with the test material sliding against a WC-Co counter face. The morphology of the worn surface and wear debris were investigated using SEM and EDS chemical analysis. FIB microscopy was applied to study sub-surface damage within the wear tracks, to aid explanation of the operative wear mechanism(s). The wear behaviour is moderately complex, transitioning from two- to three-body abrasive wear, with both steel binder extrusion and TiC fragmentation observed to contribute towards third-body formation. A further transition to adhesive wear is also observed, with tribolayer generation on both tribo pair surfaces.
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the reciprocating wear behaviour of tic 304l stainless steel composites prepared by melt infiltration
Wear, 2013Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC-based ceramic–metal composites, or cermets, are widely used in applications requiring wear and corrosion resistance. In the present work, a family of novel TiC–stainless steel (grade 304L) cermets has been developed using vacuum melt infiltration (1500 °C/1 h), with steel binder contents varied from 5 to 30 vol%. Microstructural analysis showed a homogenous distribution of TiC within the steel binder, with mean TiC grain sizes of ∼6 μm. Increasing the steel content resulted in an increase in the indentation fracture resistance and a decrease in the hardness. The reciprocating wear resistance of the cermets was assessed using a ball-on-Flat Geometry, using a WC–Co sphere dry sliding on the polished cermet surface. It was shown that there is an increase in the specific wear rate with both increasing load and binder content. Similarly, a higher coefficient of friction was observed with higher steel binder contents. The morphology of the worn surface was investigated using scanning electron microscopy, and associated energy dispersive X-ray spectroscopy, to more fully understand the operative wear mechanisms. Evidence of a transition from two- to three-body abrasive wear was observed, together with the formation of a tribolayer, indicating that adhesive wear was also occurring.
Chukwuma C Onuoha - One of the best experts on this subject based on the ideXlab platform.
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reciprocating wear behaviour of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC based cermets have been prepared with three different grades of stainless steel binder (304L, 316L and 410L). The cermets were densified by vacuum melt infiltration, at 1500 °C, which allows the steel binder content to be readily varied from 5 to 30 vol%. The cermets were assessed for their hardness and indentation fracture resistance using Vickers testing. The reciprocating wear response was evaluated using a ball on Flat Geometry, with a WC-Co counter face sphere. It was shown that the coefficient of friction increases with increasing steel binder content, and also with increasing load and wear time. Similarly, the specific wear rate increases with both steel binder content and applied load, but was largely independent of the steel grade used.
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microstructural damage following reciprocating wear of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract High density TiC-based cermets were fabricated using a simple melt-infiltration/sintering method, with three different grades of stainless steel binder. Reciprocating wear tests were conducted using a ball-on-Flat Geometry, with the test material sliding against a WC-Co counter face. The morphology of the worn surface and wear debris were investigated using SEM and EDS chemical analysis. FIB microscopy was applied to study sub-surface damage within the wear tracks, to aid explanation of the operative wear mechanism(s). The wear behaviour is moderately complex, transitioning from two- to three-body abrasive wear, with both steel binder extrusion and TiC fragmentation observed to contribute towards third-body formation. A further transition to adhesive wear is also observed, with tribolayer generation on both tribo pair surfaces.
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the reciprocating wear behaviour of tic 304l stainless steel composites prepared by melt infiltration
Wear, 2013Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC-based ceramic–metal composites, or cermets, are widely used in applications requiring wear and corrosion resistance. In the present work, a family of novel TiC–stainless steel (grade 304L) cermets has been developed using vacuum melt infiltration (1500 °C/1 h), with steel binder contents varied from 5 to 30 vol%. Microstructural analysis showed a homogenous distribution of TiC within the steel binder, with mean TiC grain sizes of ∼6 μm. Increasing the steel content resulted in an increase in the indentation fracture resistance and a decrease in the hardness. The reciprocating wear resistance of the cermets was assessed using a ball-on-Flat Geometry, using a WC–Co sphere dry sliding on the polished cermet surface. It was shown that there is an increase in the specific wear rate with both increasing load and binder content. Similarly, a higher coefficient of friction was observed with higher steel binder contents. The morphology of the worn surface was investigated using scanning electron microscopy, and associated energy dispersive X-ray spectroscopy, to more fully understand the operative wear mechanisms. Evidence of a transition from two- to three-body abrasive wear was observed, together with the formation of a tribolayer, indicating that adhesive wear was also occurring.
Eugen Radu - One of the best experts on this subject based on the ideXlab platform.
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proca stars gravitating bose einstein condensates of massive spin 1 particles
Physics Letters B, 2016Co-Authors: Richard Brito, Vitor Cardoso, Carlos A R Herdeiro, Eugen RaduAbstract:Abstract We establish that massive complex Abelian vector fields (mass μ) can form gravitating solitons, when minimally coupled to Einstein's gravity. Such Proca stars (PSs) have a stationary, everywhere regular and asymptotically Flat Geometry. The Proca field, however, possesses a harmonic time dependence (frequency w), realizing Wheeler's concept of geons for an Abelian spin 1 field. We obtain PSs with both a spherically symmetric (static) and an axially symmetric (stationary) line element. The latter form a countable number of families labelled by an integer m ∈ Z + . PSs, like (scalar) boson stars, carry a conserved Noether charge, and are akin to the latter in many ways. In particular, both types of stars exist for a limited range of frequencies and there is a maximal ADM mass, M max , attained for an intermediate frequency. For spherically symmetric PSs (rotating PSs with m = 1 , 2 , 3 ), M max ≃ 1.058 M Pl 2 / μ ( M max ≃ 1.568 , 2.337 , 3.247 M Pl 2 / μ ), slightly larger values than those for (mini-)boson stars. We establish perturbative stability for a subset of solutions in the spherical case and anticipate a similar conclusion for fundamental modes in the rotating case. The discovery of PSs opens many avenues of research, reconsidering five decades of work on (scalar) boson stars, in particular as possible dark matter candidates.
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Proca stars: Gravitating Bose–Einstein condensates of massive spin 1 particles
Physics Letters B, 2016Co-Authors: Richard Brito, Vitor Cardoso, Carlos A R Herdeiro, Eugen RaduAbstract:Abstract We establish that massive complex Abelian vector fields (mass μ) can form gravitating solitons, when minimally coupled to Einstein's gravity. Such Proca stars (PSs) have a stationary, everywhere regular and asymptotically Flat Geometry. The Proca field, however, possesses a harmonic time dependence (frequency w), realizing Wheeler's concept of geons for an Abelian spin 1 field. We obtain PSs with both a spherically symmetric (static) and an axially symmetric (stationary) line element. The latter form a countable number of families labelled by an integer m ∈ Z + . PSs, like (scalar) boson stars, carry a conserved Noether charge, and are akin to the latter in many ways. In particular, both types of stars exist for a limited range of frequencies and there is a maximal ADM mass, M max , attained for an intermediate frequency. For spherically symmetric PSs (rotating PSs with m = 1 , 2 , 3 ), M max ≃ 1.058 M Pl 2 / μ ( M max ≃ 1.568 , 2.337 , 3.247 M Pl 2 / μ ), slightly larger values than those for (mini-)boson stars. We establish perturbative stability for a subset of solutions in the spherical case and anticipate a similar conclusion for fundamental modes in the rotating case. The discovery of PSs opens many avenues of research, reconsidering five decades of work on (scalar) boson stars, in particular as possible dark matter candidates.
Georges J. Kipouros - One of the best experts on this subject based on the ideXlab platform.
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reciprocating wear behaviour of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC based cermets have been prepared with three different grades of stainless steel binder (304L, 316L and 410L). The cermets were densified by vacuum melt infiltration, at 1500 °C, which allows the steel binder content to be readily varied from 5 to 30 vol%. The cermets were assessed for their hardness and indentation fracture resistance using Vickers testing. The reciprocating wear response was evaluated using a ball on Flat Geometry, with a WC-Co counter face sphere. It was shown that the coefficient of friction increases with increasing steel binder content, and also with increasing load and wear time. Similarly, the specific wear rate increases with both steel binder content and applied load, but was largely independent of the steel grade used.
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microstructural damage following reciprocating wear of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract High density TiC-based cermets were fabricated using a simple melt-infiltration/sintering method, with three different grades of stainless steel binder. Reciprocating wear tests were conducted using a ball-on-Flat Geometry, with the test material sliding against a WC-Co counter face. The morphology of the worn surface and wear debris were investigated using SEM and EDS chemical analysis. FIB microscopy was applied to study sub-surface damage within the wear tracks, to aid explanation of the operative wear mechanism(s). The wear behaviour is moderately complex, transitioning from two- to three-body abrasive wear, with both steel binder extrusion and TiC fragmentation observed to contribute towards third-body formation. A further transition to adhesive wear is also observed, with tribolayer generation on both tribo pair surfaces.
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the reciprocating wear behaviour of tic 304l stainless steel composites prepared by melt infiltration
Wear, 2013Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC-based ceramic–metal composites, or cermets, are widely used in applications requiring wear and corrosion resistance. In the present work, a family of novel TiC–stainless steel (grade 304L) cermets has been developed using vacuum melt infiltration (1500 °C/1 h), with steel binder contents varied from 5 to 30 vol%. Microstructural analysis showed a homogenous distribution of TiC within the steel binder, with mean TiC grain sizes of ∼6 μm. Increasing the steel content resulted in an increase in the indentation fracture resistance and a decrease in the hardness. The reciprocating wear resistance of the cermets was assessed using a ball-on-Flat Geometry, using a WC–Co sphere dry sliding on the polished cermet surface. It was shown that there is an increase in the specific wear rate with both increasing load and binder content. Similarly, a higher coefficient of friction was observed with higher steel binder contents. The morphology of the worn surface was investigated using scanning electron microscopy, and associated energy dispersive X-ray spectroscopy, to more fully understand the operative wear mechanisms. Evidence of a transition from two- to three-body abrasive wear was observed, together with the formation of a tribolayer, indicating that adhesive wear was also occurring.
Zoheir Farhat - One of the best experts on this subject based on the ideXlab platform.
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reciprocating wear behaviour of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC based cermets have been prepared with three different grades of stainless steel binder (304L, 316L and 410L). The cermets were densified by vacuum melt infiltration, at 1500 °C, which allows the steel binder content to be readily varied from 5 to 30 vol%. The cermets were assessed for their hardness and indentation fracture resistance using Vickers testing. The reciprocating wear response was evaluated using a ball on Flat Geometry, with a WC-Co counter face sphere. It was shown that the coefficient of friction increases with increasing steel binder content, and also with increasing load and wear time. Similarly, the specific wear rate increases with both steel binder content and applied load, but was largely independent of the steel grade used.
-
microstructural damage following reciprocating wear of tic stainless steel cermets
Tribology International, 2017Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract High density TiC-based cermets were fabricated using a simple melt-infiltration/sintering method, with three different grades of stainless steel binder. Reciprocating wear tests were conducted using a ball-on-Flat Geometry, with the test material sliding against a WC-Co counter face. The morphology of the worn surface and wear debris were investigated using SEM and EDS chemical analysis. FIB microscopy was applied to study sub-surface damage within the wear tracks, to aid explanation of the operative wear mechanism(s). The wear behaviour is moderately complex, transitioning from two- to three-body abrasive wear, with both steel binder extrusion and TiC fragmentation observed to contribute towards third-body formation. A further transition to adhesive wear is also observed, with tribolayer generation on both tribo pair surfaces.
-
the reciprocating wear behaviour of tic 304l stainless steel composites prepared by melt infiltration
Wear, 2013Co-Authors: Chukwuma C Onuoha, Zoheir Farhat, Georges J. Kipouros, Kevin P. PlucknettAbstract:Abstract TiC-based ceramic–metal composites, or cermets, are widely used in applications requiring wear and corrosion resistance. In the present work, a family of novel TiC–stainless steel (grade 304L) cermets has been developed using vacuum melt infiltration (1500 °C/1 h), with steel binder contents varied from 5 to 30 vol%. Microstructural analysis showed a homogenous distribution of TiC within the steel binder, with mean TiC grain sizes of ∼6 μm. Increasing the steel content resulted in an increase in the indentation fracture resistance and a decrease in the hardness. The reciprocating wear resistance of the cermets was assessed using a ball-on-Flat Geometry, using a WC–Co sphere dry sliding on the polished cermet surface. It was shown that there is an increase in the specific wear rate with both increasing load and binder content. Similarly, a higher coefficient of friction was observed with higher steel binder contents. The morphology of the worn surface was investigated using scanning electron microscopy, and associated energy dispersive X-ray spectroscopy, to more fully understand the operative wear mechanisms. Evidence of a transition from two- to three-body abrasive wear was observed, together with the formation of a tribolayer, indicating that adhesive wear was also occurring.