2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al...2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al） matrix of 2A97 alloy processed by the heat treatment with no pre-stretch deformation. When the pre-stretch deformation is 3% and 6%, respectively, amounts of tiny T1 and a few of S＇ precipitates precipitates are observed in the microstructures of 2A97 alloy. The tensile test results show that the tensile properties of 2A97 alloys are improved via thermo-mechanical treatment. When the pre-stretch deformation is from 0, 3% to 6%, the ultimate tensile strength values of the 2A97 alloys increase gradually from 447.7, 516.5 to 534.3 MPa, and the elongations decrease from 17.6%, 12.8% to 10.2%, respectively. Moreover, with increasing pre-stretch deformation amount from 0 to 6%, the in-plane anisotropy value of 2A97 alloys becomes more obvious.展开更多
The fatigue crack initiation and early propagation behavior of 2A97 Al-Li alloy was studied. The smooth specimens were fatigued at room temperature under constant maximum stress control when stress ratio （R） is 0.1 ...The fatigue crack initiation and early propagation behavior of 2A97 Al-Li alloy was studied. The smooth specimens were fatigued at room temperature under constant maximum stress control when stress ratio （R） is 0.1 and frequency （f） is 40 Hz. Microstructure observations were examined by optical microscopy, transmission electron microscopy, scanning electron microscopy and electron back scattered diffusion, in order to investigate the relationship between microstructure and fatigue crack initiation and early propagation behavior of 2A97 alloy. The results show that the fatigue cracks are predominantly initiated at inclusions and coarsen secondary phases on the surface of 2A97 alloy. The fatigue crack early propagation behavior of 2A97 alloy is predominantly influenced by the interactions between grain structure and dislocations or persistent slip bands （PSBs）. When the misorientation of two neighbouring grains is close to the orientations of the favorable slip plane within these two grains, high-angle grain boundary severely hinders the PSBs passing through, and thus leads to crack bifurcation and deflection.展开更多
At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T （μi-T curves） of the Co66Fe4Mo2Si16B12 alloy were investigated using a sm...At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T （μi-T curves） of the Co66Fe4Mo2Si16B12 alloy were investigated using a small-angle magnetization tester and core tester. The experimental results showed that the μi-T curves had different shapes at different ranges of annealing temperature; the permeability μi of the alloy improved with the increase of the annealing temperatures below 460℃; when the alloy was annealed above 480℃, the poor magnetic properties were considered to be caused by larger saturation magnetostriction.展开更多
The behavior of growth and coarsening of T-1(Al2CuLi) precipitates was comparatively studied by means of TEM technique in two Al-Li alloys 2090 and 2090+Ce (with cerium content less than 0.1% in mass fraction). Statis...The behavior of growth and coarsening of T-1(Al2CuLi) precipitates was comparatively studied by means of TEM technique in two Al-Li alloys 2090 and 2090+Ce (with cerium content less than 0.1% in mass fraction). Statistical analysis results show that T-1 precipitates in alloy 2090+Ce have smaller aspect ratio, which is connected with the more intersections between different T-1 variants in this alloy. It is also found that the variation of maximum length of T-1 precipitates with aging time can be obviously divided into two stages of growth and coarsening. The diffusion coefficients of solute atoms of Cu and Li are calculated via growth kinetics curves of T-1 precipitates. The results show that the diffusion of atom Cu plays a more important role in the formation of T-1 precipitates.展开更多
2A97 Al-Li alloy was cold-rolled to 2 mm and then thermally exposed at different temperatures for 1 h and at 723 K for different time,respectively.The texture evolution behavior and the anisotropy of 2A97 Al-Li alloy ...2A97 Al-Li alloy was cold-rolled to 2 mm and then thermally exposed at different temperatures for 1 h and at 723 K for different time,respectively.The texture evolution behavior and the anisotropy of 2A97 Al-Li alloy were investigated.The result shows that the{001}<120>and{011}<233>textures are the dominant recrystallization texture.The{124}<211>texture is the final recrystallization texture.In case of low-temperature thermal exposure(473,573 K),the{011}<211>texture is aggregated to the{112}<111>and{123}<634>textures.During the recrystallization at 723 K,the{001}<110>,{111}<112>and{011}<100>textures are the intermediate transition grain orientations.The concurrent precipitation of Al_(20)Cu_(2)Mn_(3)and Al_(3)Zr results in the occurrence of unusually sharp{011}<233>and{001}<120>texture components during recrystallization.The alloy with both recrystallization and deformation texture possesses the smallest anisotropic,and the texture is the direct reason that results in the anisotropy.展开更多
文摘2A97 Al-Li alloy was processed by thermo-mechanical treatment at different pre-stretch deformations of 0, 3% and 6%. The microstrucatre observation results reveal that some δ＇ and T1 precipitates are found in a（Al） matrix of 2A97 alloy processed by the heat treatment with no pre-stretch deformation. When the pre-stretch deformation is 3% and 6%, respectively, amounts of tiny T1 and a few of S＇ precipitates precipitates are observed in the microstructures of 2A97 alloy. The tensile test results show that the tensile properties of 2A97 alloys are improved via thermo-mechanical treatment. When the pre-stretch deformation is from 0, 3% to 6%, the ultimate tensile strength values of the 2A97 alloys increase gradually from 447.7, 516.5 to 534.3 MPa, and the elongations decrease from 17.6%, 12.8% to 10.2%, respectively. Moreover, with increasing pre-stretch deformation amount from 0 to 6%, the in-plane anisotropy value of 2A97 alloys becomes more obvious.
文摘The fatigue crack initiation and early propagation behavior of 2A97 Al-Li alloy was studied. The smooth specimens were fatigued at room temperature under constant maximum stress control when stress ratio （R） is 0.1 and frequency （f） is 40 Hz. Microstructure observations were examined by optical microscopy, transmission electron microscopy, scanning electron microscopy and electron back scattered diffusion, in order to investigate the relationship between microstructure and fatigue crack initiation and early propagation behavior of 2A97 alloy. The results show that the fatigue cracks are predominantly initiated at inclusions and coarsen secondary phases on the surface of 2A97 alloy. The fatigue crack early propagation behavior of 2A97 alloy is predominantly influenced by the interactions between grain structure and dislocations or persistent slip bands （PSBs）. When the misorientation of two neighbouring grains is close to the orientations of the favorable slip plane within these two grains, high-angle grain boundary severely hinders the PSBs passing through, and thus leads to crack bifurcation and deflection.
文摘At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T （μi-T curves） of the Co66Fe4Mo2Si16B12 alloy were investigated using a small-angle magnetization tester and core tester. The experimental results showed that the μi-T curves had different shapes at different ranges of annealing temperature; the permeability μi of the alloy improved with the increase of the annealing temperatures below 460℃; when the alloy was annealed above 480℃, the poor magnetic properties were considered to be caused by larger saturation magnetostriction.
文摘The behavior of growth and coarsening of T-1(Al2CuLi) precipitates was comparatively studied by means of TEM technique in two Al-Li alloys 2090 and 2090+Ce (with cerium content less than 0.1% in mass fraction). Statistical analysis results show that T-1 precipitates in alloy 2090+Ce have smaller aspect ratio, which is connected with the more intersections between different T-1 variants in this alloy. It is also found that the variation of maximum length of T-1 precipitates with aging time can be obviously divided into two stages of growth and coarsening. The diffusion coefficients of solute atoms of Cu and Li are calculated via growth kinetics curves of T-1 precipitates. The results show that the diffusion of atom Cu plays a more important role in the formation of T-1 precipitates.
基金financially supported by the National Natural Science Foundation of China(Nos.U1537212,51471019 and 51271011)the National Key Research and Development Program of China(No.2016YFB0300901)。
文摘2A97 Al-Li alloy was cold-rolled to 2 mm and then thermally exposed at different temperatures for 1 h and at 723 K for different time,respectively.The texture evolution behavior and the anisotropy of 2A97 Al-Li alloy were investigated.The result shows that the{001}<120>and{011}<233>textures are the dominant recrystallization texture.The{124}<211>texture is the final recrystallization texture.In case of low-temperature thermal exposure(473,573 K),the{011}<211>texture is aggregated to the{112}<111>and{123}<634>textures.During the recrystallization at 723 K,the{001}<110>,{111}<112>and{011}<100>textures are the intermediate transition grain orientations.The concurrent precipitation of Al_(20)Cu_(2)Mn_(3)and Al_(3)Zr results in the occurrence of unusually sharp{011}<233>and{001}<120>texture components during recrystallization.The alloy with both recrystallization and deformation texture possesses the smallest anisotropic,and the texture is the direct reason that results in the anisotropy.
