The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Bandar Almangour - One of the best experts on this subject based on the ideXlab platform.
-
Strengthening of stainless steel by titanium carbide addition and Grain refinement during selective laser melting
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Bandar Almangour, Dariusz Grzesiak, Minseok Baek, Keeahn LeeAbstract:Abstract This study clarifies the role of micro- and nano-TiC added to 316L stainless steel fabricated by the selective laser melting (SLM) process, an emerging additive manufacturing technology, in the microstructural evolution and mechanical properties. Directionally fine cellular dendrites and columnar Grains formed during the fast solidification in SLM-processed stainless steel. Interestingly, the addition of TiC particles in the steel matrix significantly reduced the cellular and Grain sizes after solidification and also disrupted the established directional structures, particularly for nanoscale TiC. The composite, particularly with nanoscale TiC, also exhibited greater room- and high-temperature compressive yield strengths than unreinforced steel, mainly because of the combined effects of Grain-Boundary Strengthening and Orowan Strengthening. The Strengthening effect was well described by the Zener pinning model. The compressed surfaces suggest that TiC particles hinder crack propagation, and the TiC distribution was critical in improving the mechanical properties. The SLM process can tailor the microstructure across a rather limited length scale; hence, to better control the mechanical properties of the resulting products, compositing the relevant feedstock powder is a highly attractive strategy for developing components with novel structures and unique properties.
-
rapid fabrication of bulk form tib2 316l stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting
Journal of Alloys and Compounds, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB 2 /316L stainless steel nanocomposites with varying nanoscale TiB 2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB 2 content. The optimal TiB 2 content was determined to be 10 vol.%. Further, the TiB 2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the Grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB 2 /316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests.
-
rapid fabrication of bulk form tib2 316l stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting
Journal of Alloys and Compounds, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB 2 /316L stainless steel nanocomposites with varying nanoscale TiB 2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB 2 content. The optimal TiB 2 content was determined to be 10 vol.%. Further, the TiB 2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the Grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB 2 /316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests.
-
selective laser melting of tic reinforced 316l stainless steel matrix nanocomposites influence of starting tic particle size and volume content
Materials & Design, 2016Co-Authors: Bandar Almangour, Dariusz GrzesiakAbstract:Abstract Selective laser melting (SLM), an additive manufacturing technology, was utilized to process TiC/316L nanocomposite systems with different starting TiC particle sizes and volume contents. The influence of the starting TiC particle size and volume content on the constitutional phases, microstructural features, and mechanical properties of the SLM-processed nanocomposite parts was investigated. The densification behavior was controlled by both the starting TiC content and the particle size; the densification level was enhanced with the use of fine starting TiC particles owing to the improvement of the reinforcement–matrix wettability. In general, by increasing the volume content of the TiC, the hardness increased and the coefficient of friction (COF) and wear rate deceased owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. However, in contrast to the starting coarse TiC particles, the SLM-part processed with the starting fine TiC particles shows better wear resistance, in particular at a 10–15% TiC content, owing to improved TiC dispersion throughout the matrix and increased density.
-
nanocrystalline tic reinforced h13 steel matrix nanocomposites fabricated by selective laser melting
Materials & Design, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Additive manufacturing (AM) has a strong potential for the formation of a new class of multifunctional nanocomposites. In this study, nanocomposite feedstock powders were prepared by a mechanical alloying method based on high-energy ball milling. The evolution of constitutional phases and microstructural features of the milled powders was investigated as a function of milling time. The results showed that the milled powder particles experienced significant cold-welding during the entire milling time, with a wide size distribution. Selective laser melting (SLM), a promising AM fabrication technique, was applied to produce nanoscale 15% (by volume) TiC-reinforced H13 steel matrix nanocomposites. After SLM, uniformly dispersed nanoscale TiC particles with a mean particle size of 50 nm were obtained and a fine heterogeneous structure was observed. Relative to the unreinforced H13 steel part, the TiC/H13 steel nanocomposite parts exhibited higher hardness and elastic modulus, along with lower friction and a lower wear rate; these improvements are attributed to the combined effects of Grain refinement and Grain Boundary Strengthening.
Dariusz Grzesiak - One of the best experts on this subject based on the ideXlab platform.
-
Strengthening of stainless steel by titanium carbide addition and Grain refinement during selective laser melting
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Bandar Almangour, Dariusz Grzesiak, Minseok Baek, Keeahn LeeAbstract:Abstract This study clarifies the role of micro- and nano-TiC added to 316L stainless steel fabricated by the selective laser melting (SLM) process, an emerging additive manufacturing technology, in the microstructural evolution and mechanical properties. Directionally fine cellular dendrites and columnar Grains formed during the fast solidification in SLM-processed stainless steel. Interestingly, the addition of TiC particles in the steel matrix significantly reduced the cellular and Grain sizes after solidification and also disrupted the established directional structures, particularly for nanoscale TiC. The composite, particularly with nanoscale TiC, also exhibited greater room- and high-temperature compressive yield strengths than unreinforced steel, mainly because of the combined effects of Grain-Boundary Strengthening and Orowan Strengthening. The Strengthening effect was well described by the Zener pinning model. The compressed surfaces suggest that TiC particles hinder crack propagation, and the TiC distribution was critical in improving the mechanical properties. The SLM process can tailor the microstructure across a rather limited length scale; hence, to better control the mechanical properties of the resulting products, compositing the relevant feedstock powder is a highly attractive strategy for developing components with novel structures and unique properties.
-
rapid fabrication of bulk form tib2 316l stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting
Journal of Alloys and Compounds, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB 2 /316L stainless steel nanocomposites with varying nanoscale TiB 2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB 2 content. The optimal TiB 2 content was determined to be 10 vol.%. Further, the TiB 2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the Grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB 2 /316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests.
-
rapid fabrication of bulk form tib2 316l stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting
Journal of Alloys and Compounds, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB 2 /316L stainless steel nanocomposites with varying nanoscale TiB 2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB 2 content. The optimal TiB 2 content was determined to be 10 vol.%. Further, the TiB 2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the Grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB 2 /316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests.
-
selective laser melting of tic reinforced 316l stainless steel matrix nanocomposites influence of starting tic particle size and volume content
Materials & Design, 2016Co-Authors: Bandar Almangour, Dariusz GrzesiakAbstract:Abstract Selective laser melting (SLM), an additive manufacturing technology, was utilized to process TiC/316L nanocomposite systems with different starting TiC particle sizes and volume contents. The influence of the starting TiC particle size and volume content on the constitutional phases, microstructural features, and mechanical properties of the SLM-processed nanocomposite parts was investigated. The densification behavior was controlled by both the starting TiC content and the particle size; the densification level was enhanced with the use of fine starting TiC particles owing to the improvement of the reinforcement–matrix wettability. In general, by increasing the volume content of the TiC, the hardness increased and the coefficient of friction (COF) and wear rate deceased owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. However, in contrast to the starting coarse TiC particles, the SLM-part processed with the starting fine TiC particles shows better wear resistance, in particular at a 10–15% TiC content, owing to improved TiC dispersion throughout the matrix and increased density.
-
nanocrystalline tic reinforced h13 steel matrix nanocomposites fabricated by selective laser melting
Materials & Design, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Additive manufacturing (AM) has a strong potential for the formation of a new class of multifunctional nanocomposites. In this study, nanocomposite feedstock powders were prepared by a mechanical alloying method based on high-energy ball milling. The evolution of constitutional phases and microstructural features of the milled powders was investigated as a function of milling time. The results showed that the milled powder particles experienced significant cold-welding during the entire milling time, with a wide size distribution. Selective laser melting (SLM), a promising AM fabrication technique, was applied to produce nanoscale 15% (by volume) TiC-reinforced H13 steel matrix nanocomposites. After SLM, uniformly dispersed nanoscale TiC particles with a mean particle size of 50 nm were obtained and a fine heterogeneous structure was observed. Relative to the unreinforced H13 steel part, the TiC/H13 steel nanocomposite parts exhibited higher hardness and elastic modulus, along with lower friction and a lower wear rate; these improvements are attributed to the combined effects of Grain refinement and Grain Boundary Strengthening.
Jennming Yang - One of the best experts on this subject based on the ideXlab platform.
-
rapid fabrication of bulk form tib2 316l stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting
Journal of Alloys and Compounds, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB 2 /316L stainless steel nanocomposites with varying nanoscale TiB 2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB 2 content. The optimal TiB 2 content was determined to be 10 vol.%. Further, the TiB 2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the Grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB 2 /316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests.
-
rapid fabrication of bulk form tib2 316l stainless steel nanocomposites with novel reinforcement architecture and improved performance by selective laser melting
Journal of Alloys and Compounds, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Selective laser melting (SLM), a novel additive manufacturing technology, was employed to fabricate nanostructured TiB 2 /316L stainless steel nanocomposites with varying nanoscale TiB 2 content (vol.%). The resulting microstructure of the SLM-processed nanocomposites was characterized by SEM, EBSD, and TEM, while the mechanical properties were characterized using microhardness, compression tests, and wear tests. It was found that the microstructure and mechanical properties of the SLM-processed nanocomposites were sensitive to the TiB 2 content. The optimal TiB 2 content was determined to be 10 vol.%. Further, the TiB 2 particles were homogeneously dispersed and they formed nanoscale ring-like structures along the Grain boundaries. In contrast to the SLM-processed unreinforced 316L stainless steel sample, the TiB 2 /316L nanocomposites exhibited higher microhardnesses and yield strengths while showing low coefficients of friction and wear rates; this was owing to the combined effects of Grain refinement and Grain-Boundary Strengthening. The nanocomposites showed good combination of compression yield strength and ductility during microcompression tests.
-
nanocrystalline tic reinforced h13 steel matrix nanocomposites fabricated by selective laser melting
Materials & Design, 2016Co-Authors: Bandar Almangour, Dariusz Grzesiak, Jennming YangAbstract:Abstract Additive manufacturing (AM) has a strong potential for the formation of a new class of multifunctional nanocomposites. In this study, nanocomposite feedstock powders were prepared by a mechanical alloying method based on high-energy ball milling. The evolution of constitutional phases and microstructural features of the milled powders was investigated as a function of milling time. The results showed that the milled powder particles experienced significant cold-welding during the entire milling time, with a wide size distribution. Selective laser melting (SLM), a promising AM fabrication technique, was applied to produce nanoscale 15% (by volume) TiC-reinforced H13 steel matrix nanocomposites. After SLM, uniformly dispersed nanoscale TiC particles with a mean particle size of 50 nm were obtained and a fine heterogeneous structure was observed. Relative to the unreinforced H13 steel part, the TiC/H13 steel nanocomposite parts exhibited higher hardness and elastic modulus, along with lower friction and a lower wear rate; these improvements are attributed to the combined effects of Grain refinement and Grain Boundary Strengthening.
U Ramamurty - One of the best experts on this subject based on the ideXlab platform.
-
nano Graining a particle strengthened high entropy alloy
Scripta Materialia, 2019Co-Authors: Dong Hyun Lee, Jeong Min Park, Guanghui Yang, Jinyoo Suh, Megumi Kawasaki, U Ramamurty, Jaeil JangAbstract:Abstract The possibility of further enhancing the strength of a (CoCrFeNi)94Ti2Al4 high-entropy alloy (HEA), which is already strengthened by Ni3(Ti,Al) second-phase particles, by Grain refinement through high-pressure torsion (HPT) is examined. Concomitant with nanoGrain formation, HPT was found to induce particle dissolution and structural transformation of the remnant particles. Nanoindentation experiments of nanocrystalline HEA, with and without particles in the pre-HPT microstructure, suggests that Grain Boundary Strengthening is the dominant Strengthening mechanism.
-
enhancing the high temperature plasticity of a cu containing austenitic stainless steel through Grain Boundary Strengthening
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Gaurav Singh, U Ramamurty, Sungmin Hong, K Ohishi, K Hono, Eric FleuryAbstract:Abstract The addition of 3 wt% Cu to heat-resistant SUS 304H austenitic steel enhances its high temperature mechanical properties. To further improve the properties, particularly the creep resistance and ductility at high temperatures, a post-solutionizing heat-treatment method that involves an intermediated annealing either at 700 or 800 °C after solutionizing for durations up to 180 min was employed. The purpose this heat-treatment is to precipitate planar Cr 23 C 6 at the Grain boundaries, which results in the boundaries getting serrated. Detailed microstructural analyses of these ‘Grain Boundary engineered’ alloys was conducted and their mechanical performance, both at room temperature and at 750 °C, was evaluated. While the Grain size and texture are unaffected due to the high temperature hold, the volume fraction of Ʃ3 twin boundaries was found to increase significantly. While the strength enhancement was only marginal, the ductility was found to increase significantly, especially at high temperature. A marked increase in the creep resistance was also noted, which is attributed to the reduction of the Grain Boundary sliding by the Grain Boundary serrations and the suppression of Grain Boundary cavitation through the optimization of the volume fraction and spacing of the Cr 23 C 6 precipitates. The special heat-treatment performed with holding time of 3 h at 700 °C resulted in the optimum combination of strength, ductility and creep resistance at high temperature.
Keeahn Lee - One of the best experts on this subject based on the ideXlab platform.
-
Strengthening of stainless steel by titanium carbide addition and Grain refinement during selective laser melting
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Bandar Almangour, Dariusz Grzesiak, Minseok Baek, Keeahn LeeAbstract:Abstract This study clarifies the role of micro- and nano-TiC added to 316L stainless steel fabricated by the selective laser melting (SLM) process, an emerging additive manufacturing technology, in the microstructural evolution and mechanical properties. Directionally fine cellular dendrites and columnar Grains formed during the fast solidification in SLM-processed stainless steel. Interestingly, the addition of TiC particles in the steel matrix significantly reduced the cellular and Grain sizes after solidification and also disrupted the established directional structures, particularly for nanoscale TiC. The composite, particularly with nanoscale TiC, also exhibited greater room- and high-temperature compressive yield strengths than unreinforced steel, mainly because of the combined effects of Grain-Boundary Strengthening and Orowan Strengthening. The Strengthening effect was well described by the Zener pinning model. The compressed surfaces suggest that TiC particles hinder crack propagation, and the TiC distribution was critical in improving the mechanical properties. The SLM process can tailor the microstructure across a rather limited length scale; hence, to better control the mechanical properties of the resulting products, compositing the relevant feedstock powder is a highly attractive strategy for developing components with novel structures and unique properties.
