A new rhombohedral phase(termed R′)in a solution-aging-treated titanium alloy(Ti-4.5Al-6.5Mo-2Cr-2Nb-1V-1Sn-1Zr,wt.%)was identified.Its accurate Bravais lattice parameters were determined by a novel unit cell reconst...A new rhombohedral phase(termed R′)in a solution-aging-treated titanium alloy(Ti-4.5Al-6.5Mo-2Cr-2Nb-1V-1Sn-1Zr,wt.%)was identified.Its accurate Bravais lattice parameters were determined by a novel unit cell reconstruction method based on conventional selected-area electron diffraction(SAED)technique.The orientation relationship between R'phase and BCC phase was revealed.The results show that the R′phase is found to have 48crystallographically equivalent variants,resulting in rather complicated SAED patterns with high-order reflections.A series of in-situ SAED patterns were taken along both low-and high-index zone axes,and all weak and strong reflections arising from the 48 variants were properly explained and directly assigned with self-consistent Miller indices,confirming the presence of the rhombohedral phase.Additionally,some criteria were also proposed for evaluating the indexed results,which together with the Bravais lattice reconstruction method shed light on the microstructure characterization of even unknown phases in other alloys.展开更多
YBa2Cu3O7-x （YBCO） superconducting film was fabricated on {001} LaAlO3 （LAO） substrate by pulse laser deposition （PLD）, and its microstructure was examined by high resolution X-ray diffraction technology （HRXRD...YBa2Cu3O7-x （YBCO） superconducting film was fabricated on {001} LaAlO3 （LAO） substrate by pulse laser deposition （PLD）, and its microstructure was examined by high resolution X-ray diffraction technology （HRXRD）, such as pole figure, rocking curve, reciprocal space mapping. The results show that the YBCO crystalline alignment is almost {001}YBCO//{001}LAO, 100YBCO//100LAO besides 2% {001}YBCO//{001}LAO, 110YBCO//100LAO. The out-plane alignment of YBCO is some spreading （the breadth is 0.75°）. There are 90°±0.65°110 twin domains in the film, which is caused by the high local stress and stress difference between 100 and 010 during the tetragonal to orthorhombic phase transition.展开更多
The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersio...The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersion testing in exfoliation corrosion solution, and electrochemical testing. The results show that the corrosion rates of different orientations of the aged Al-Cu-Li alloy increase in the order of (001) 1 phase deteriorated the corrosion resistance of the Al-Cu-Li alloy, and the degree of deterioration differed in different crystal plane orientations. The severe localized corrosion of the aged alloy propagates along the crystallography and extends along the {111}Alplane in the form of corrosion bands.展开更多
Multiple characterization and analysis techniques including electron backscatter diffraction（EBSD）, electron channeling contrast（ECC） imaging, transmission electron microscopy（TEM） and microhardness test were jo...Multiple characterization and analysis techniques including electron backscatter diffraction（EBSD）, electron channeling contrast（ECC） imaging, transmission electron microscopy（TEM） and microhardness test were jointly employed to investigate microstructural characteristics such as local composition, morphology, grain boundary characteristics and interphase orientation relationship of a forged Zr-2.5Nb alloy before and after β-air-cooling. Results show that the as-forged specimen is composed of equiaxed and lamellar α grains and continuous net-like β-Zr films. After the β-air-cooling, the microstructure of the specimen is featured by basket-weave Widmanst？tten structure, in which the inter-α-plate second phases are nanoscale β-Zr. Analyses for crystallographic orientations reveal that the Burgers relationship has been strictly followed during the β→α cooling. Compared to the as-forged specimen, the hardness of the β-air-cooled specimen is higher, which could be attributed to the decreased structural sizes of both α and β phases, and the increased fraction of high angle boundaries as well.展开更多
基金financial supports from the National Natural Science Foundation of China(No.51071125)the Major Project of Department of Education of Jiangxi Province,China(No.GJJ210605)。
文摘A new rhombohedral phase(termed R′)in a solution-aging-treated titanium alloy(Ti-4.5Al-6.5Mo-2Cr-2Nb-1V-1Sn-1Zr,wt.%)was identified.Its accurate Bravais lattice parameters were determined by a novel unit cell reconstruction method based on conventional selected-area electron diffraction(SAED)technique.The orientation relationship between R'phase and BCC phase was revealed.The results show that the R′phase is found to have 48crystallographically equivalent variants,resulting in rather complicated SAED patterns with high-order reflections.A series of in-situ SAED patterns were taken along both low-and high-index zone axes,and all weak and strong reflections arising from the 48 variants were properly explained and directly assigned with self-consistent Miller indices,confirming the presence of the rhombohedral phase.Additionally,some criteria were also proposed for evaluating the indexed results,which together with the Bravais lattice reconstruction method shed light on the microstructure characterization of even unknown phases in other alloys.
基金Project (50972019) supported by the National Natural Science Foundation of ChinaProject (2011CBA00105) supported by the National Basic Research Program of China
文摘YBa2Cu3O7-x （YBCO） superconducting film was fabricated on {001} LaAlO3 （LAO） substrate by pulse laser deposition （PLD）, and its microstructure was examined by high resolution X-ray diffraction technology （HRXRD）, such as pole figure, rocking curve, reciprocal space mapping. The results show that the YBCO crystalline alignment is almost {001}YBCO//{001}LAO, 100YBCO//100LAO besides 2% {001}YBCO//{001}LAO, 110YBCO//100LAO. The out-plane alignment of YBCO is some spreading （the breadth is 0.75°）. There are 90°±0.65°110 twin domains in the film, which is caused by the high local stress and stress difference between 100 and 010 during the tetragonal to orthorhombic phase transition.
基金the financial support from the National Natural Science Foundation of China (No. 51961013)the Natural Science Foundation of Jiangxi Province, China (No. 20202ACBL214002)+2 种基金the China Postdoctoral Science Foundation (Nos. 2019M660159 and 2020T130093)the Postdoctoral Science Foundation of Jiangxi Province, China (No. 2019KY25)the Program of Qingjiang Excellent Young Talents of Jiangxi University of Science and Technology, China (No. JXUSTQJYX2020022)。
文摘The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersion testing in exfoliation corrosion solution, and electrochemical testing. The results show that the corrosion rates of different orientations of the aged Al-Cu-Li alloy increase in the order of (001) 1 phase deteriorated the corrosion resistance of the Al-Cu-Li alloy, and the degree of deterioration differed in different crystal plane orientations. The severe localized corrosion of the aged alloy propagates along the crystallography and extends along the {111}Alplane in the form of corrosion bands.
基金Project(51401040) supported by the National Natural Science Foundation of ChinaProject(CSTC2017JCYJAX0114) supported by the Fundamental and Cutting-edge Research Plan of Chongqing,China+1 种基金Project(E2015203250) supported by the Natural Science Foundation of Hebei Province,ChinaProject(14LGA005) supported by the Young Teachers Program of Yanshan University,China
文摘Multiple characterization and analysis techniques including electron backscatter diffraction（EBSD）, electron channeling contrast（ECC） imaging, transmission electron microscopy（TEM） and microhardness test were jointly employed to investigate microstructural characteristics such as local composition, morphology, grain boundary characteristics and interphase orientation relationship of a forged Zr-2.5Nb alloy before and after β-air-cooling. Results show that the as-forged specimen is composed of equiaxed and lamellar α grains and continuous net-like β-Zr films. After the β-air-cooling, the microstructure of the specimen is featured by basket-weave Widmanst？tten structure, in which the inter-α-plate second phases are nanoscale β-Zr. Analyses for crystallographic orientations reveal that the Burgers relationship has been strictly followed during the β→α cooling. Compared to the as-forged specimen, the hardness of the β-air-cooled specimen is higher, which could be attributed to the decreased structural sizes of both α and β phases, and the increased fraction of high angle boundaries as well.
