The effect of base material(BM) on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grain...The effect of base material(BM) on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains was studied by advanced electron backscattered diffraction data processing. The inhomogeneity of microstructure within welded joint was formed due to the different microstructures of BM. By comparing microstructure details of the welded joint, including microstructure morphology and crystallographic orientation with those of the base material, it can be found that both the microstructure morphology and crystallographic orientation of the EBW joint would be controlled by BM.展开更多
The evolution of the microstructure and texture in copper has been studied during repetitive extrusionupsetting(REU) to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It i...The evolution of the microstructure and texture in copper has been studied during repetitive extrusionupsetting(REU) to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It is found that the texture is significantly altered by each deformation pass. A duplex 001 + 111 fiber texture with an increased 111 component is observed after each extrusion pass,whereas the 110 fiber component dominates the texture after each upsetting pass. During REU, the microstructure is refined by deformation-induced boundaries. The average cell size after a total strain of 4.7 is measured to be ~0.3 μm. This refined microstructure is unstable at room temperature as is evident from the presence of a small number of recrystallized grains in the deformed matrix. Pronounced recrystallization took place during annealing at 200?C for 1 h with recrystallized grains developing predominantly in high misorientation regions. At 350?C the microstructure is fully recrystallized with an average grain size of only 2.3 μm and a very weak crystallographic texture. This REU-processed and subsequently annealed material is considered to be potentially suitable for using as a material for sputtering targets.展开更多
How to manufacture the high magnetic induction grain-oriented silicon steel(Hi-B steel)by the process featured with the primary recrystallization annealing was demonstrated,during which nitriding and decarburizing w...How to manufacture the high magnetic induction grain-oriented silicon steel(Hi-B steel)by the process featured with the primary recrystallization annealing was demonstrated,during which nitriding and decarburizing were simultaneously realized in laboratory.By the techniques of optical microscope,scanning electronic microscope and electron backscattered diffraction,both the microstructure and the texture in the samples were characterized.The samples had been subjected to nitriding to different nitrogen contents at two specified temperatures using the two defined microstructural parameters:the grain size inhomogeneity factorσ*and the texture factor AR.The former is the ratio of the mean value to standard deviation of grain sizes;the latter is the ratio of the total volume fraction of the harmful textures to that of beneficial textures including {110}〈001〉.When the N content increased from 0.0055%to 0.0330%after the annealing at both 835 and 875°C,the resultant recrystallized grain size decreased butσ*changed little;whilst the rise of annealing temperature from 835 to 875°C resulted in the increase in both grain size andσ*.Moreover,either the injected N content or temperature had insignificant influence on the components of primary recrystallization texture developed during annealing.However,the increase of temperature led to the decreases in both intensity and volume fraction of{001}〈120〉and{110}〈001〉textures but increases in the{114}〈481〉andγfiber textures and the resultant decrease of AR.展开更多
A liquid-assisted shear exfoliation (LASE) as a new powder metallurgy method coupled with spark plasmasintering (SPS) was applied for n-type Bi_(2)Te_(2.7)Se_(0.3) and the effects on microstructure and anisotropictran...A liquid-assisted shear exfoliation (LASE) as a new powder metallurgy method coupled with spark plasmasintering (SPS) was applied for n-type Bi_(2)Te_(2.7)Se_(0.3) and the effects on microstructure and anisotropictransport properties were investigated. Results revealed an effective reduction of average grain size dueto LASE and a high texturing in the bulks. Moreover, along the in-plane direction, electrical conductivitywas increased noticeably due to an enhanced carrier concentration, leading to a significantly improvedpower factor of 25 μW cm^(–1) K^(–2) at 303 K. Meanwhile, the total thermal conductivity was reduced effectively owing to reduction both in lattice component due to enhanced phonon scattering with the grainsize reduction, and in the bipolar component inhibited by the increased carrier concentration. Ultimately,a peak thermoelectric figure of merit (ZT) value of 0.83 was obtained at 448 K along the in-plane direction, increased by 95% compared with the pristine one. These results demonstrate the LASE process as auseful assistant method for enhancing the TE performance of layered materials.展开更多
文摘The effect of base material(BM) on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains was studied by advanced electron backscattered diffraction data processing. The inhomogeneity of microstructure within welded joint was formed due to the different microstructures of BM. By comparing microstructure details of the welded joint, including microstructure morphology and crystallographic orientation with those of the base material, it can be found that both the microstructure morphology and crystallographic orientation of the EBW joint would be controlled by BM.
基金supported by the Chongqing Research Program of Basic Research and Frontier Technology (No. cstc2015jcyj BX0115)support of the “111” Project (B16007) by the Ministry of Education and the State Administration of Foreign Experts Affairs of Chinathe National Natural Science Foundation of China (Nos. 51471039, 51421001)
文摘The evolution of the microstructure and texture in copper has been studied during repetitive extrusionupsetting(REU) to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It is found that the texture is significantly altered by each deformation pass. A duplex 001 + 111 fiber texture with an increased 111 component is observed after each extrusion pass,whereas the 110 fiber component dominates the texture after each upsetting pass. During REU, the microstructure is refined by deformation-induced boundaries. The average cell size after a total strain of 4.7 is measured to be ~0.3 μm. This refined microstructure is unstable at room temperature as is evident from the presence of a small number of recrystallized grains in the deformed matrix. Pronounced recrystallization took place during annealing at 200?C for 1 h with recrystallized grains developing predominantly in high misorientation regions. At 350?C the microstructure is fully recrystallized with an average grain size of only 2.3 μm and a very weak crystallographic texture. This REU-processed and subsequently annealed material is considered to be potentially suitable for using as a material for sputtering targets.
基金financially sponsored by the State Key Special Project of Key Basic Material Technical Promotion and Industrialization(2016YFB0300305)
文摘How to manufacture the high magnetic induction grain-oriented silicon steel(Hi-B steel)by the process featured with the primary recrystallization annealing was demonstrated,during which nitriding and decarburizing were simultaneously realized in laboratory.By the techniques of optical microscope,scanning electronic microscope and electron backscattered diffraction,both the microstructure and the texture in the samples were characterized.The samples had been subjected to nitriding to different nitrogen contents at two specified temperatures using the two defined microstructural parameters:the grain size inhomogeneity factorσ*and the texture factor AR.The former is the ratio of the mean value to standard deviation of grain sizes;the latter is the ratio of the total volume fraction of the harmful textures to that of beneficial textures including {110}〈001〉.When the N content increased from 0.0055%to 0.0330%after the annealing at both 835 and 875°C,the resultant recrystallized grain size decreased butσ*changed little;whilst the rise of annealing temperature from 835 to 875°C resulted in the increase in both grain size andσ*.Moreover,either the injected N content or temperature had insignificant influence on the components of primary recrystallization texture developed during annealing.However,the increase of temperature led to the decreases in both intensity and volume fraction of{001}〈120〉and{110}〈001〉textures but increases in the{114}〈481〉andγfiber textures and the resultant decrease of AR.
基金This work was financially supported by the National Natural Science Foundation of China(No.51672127)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘A liquid-assisted shear exfoliation (LASE) as a new powder metallurgy method coupled with spark plasmasintering (SPS) was applied for n-type Bi_(2)Te_(2.7)Se_(0.3) and the effects on microstructure and anisotropictransport properties were investigated. Results revealed an effective reduction of average grain size dueto LASE and a high texturing in the bulks. Moreover, along the in-plane direction, electrical conductivitywas increased noticeably due to an enhanced carrier concentration, leading to a significantly improvedpower factor of 25 μW cm^(–1) K^(–2) at 303 K. Meanwhile, the total thermal conductivity was reduced effectively owing to reduction both in lattice component due to enhanced phonon scattering with the grainsize reduction, and in the bipolar component inhibited by the increased carrier concentration. Ultimately,a peak thermoelectric figure of merit (ZT) value of 0.83 was obtained at 448 K along the in-plane direction, increased by 95% compared with the pristine one. These results demonstrate the LASE process as auseful assistant method for enhancing the TE performance of layered materials.