On the basis of the thermodynamic analysis and fundamental study in the laboratory, the equilibrium of the Ti A10 system was investigated. The results showed that the equilibrium titanium content in the steel increase...On the basis of the thermodynamic analysis and fundamental study in the laboratory, the equilibrium of the Ti A10 system was investigated. The results showed that the equilibrium titanium content in the steel increased with the increase in the soluble aluminum content in the steel and the TiO2 content in the slag. Although the slag basicity decreased and Al2O3 content in the slag increased, the titanium content increased. Based on these results, the BOF smelting process of low titanium bearing steel was put forward.展开更多
A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer. The electrolyzing results show that producing Al based alloys wi...A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer. The electrolyzing results show that producing Al based alloys with titanium contents of less than 0.30% without great loss of electrolysis efficiency is possible. The quantitative analysis shows that this method has a great refining effect on transiting the coarse columnar grains in pure Al to equiaxed grains. The grain sizes decrease with the increase of titanium content and tend to a low limit at about 130 μm. During the solidification, the non equilibrium distribution of titanium leads to a great growth restricting effect and a constitutional under cooling zone in front of the growing liquid /solid interface.展开更多
Two linear regression models based on absorption features extracted from CE-1 IIM image data are presented to discuss the relationship between absorption features and titanium content. We computed five absorption para...Two linear regression models based on absorption features extracted from CE-1 IIM image data are presented to discuss the relationship between absorption features and titanium content. We computed five absorption parameters (Full Wave at Half Maximum (FWHM), absorption position, absorption area, absorption depth and absorption asymmetry) of the spectra collected at Apollo 17 landing sites to build two regression models, one with FWHM and the other without FWHM due to the low relation coefficient between FWHM and Ti content. Finally Ti content measured from Apollo 17 samples and Apollo 16 samples was used to test the accuracy. The results show that the predicted values of the model with FWHM have many singular values and the result of model without FWHM is more stable. The two models are relatively accurate for high-Ti districts, while seem inexact and disable for low-Ti districts.展开更多
A series of Ti–Al–V titanium alloy bars with nominal composition Ti–7Al–5V ELI,Ti–5Al–3V ELI,commercial Ti–6Al–4V ELI and commercial Ti–6Al–4V were prepared.These alloys were then heat treated to obtain bimo...A series of Ti–Al–V titanium alloy bars with nominal composition Ti–7Al–5V ELI,Ti–5Al–3V ELI,commercial Ti–6Al–4V ELI and commercial Ti–6Al–4V were prepared.These alloys were then heat treated to obtain bimodal or equiaxed microstructures with various contents of primary a phase.Dynamic compression properties of the alloys above were studied by split Hopkinson pressure bar system at strain rates from 2,000 to 4,000 s-1.The results show that Ti–6Al–4V alloy with equiaxed primary a(ap)volume fraction of 45 vol%or 67 vol%exhibits good dynamic properties with high dynamic strength and absorbed energy,as well as an acceptable dynamic plasticity.However,all the Ti53ELI specimens and Ti64ELI specimens with ap of 65 vol%were not fractured at a strain rate of4,000 s-1.It appears that the undamaged specimens still have load-bearing capability.Dynamic strength of Ti–Al–V alloy can be improved as the contents of elements Al,V,Fe,and O increase,while dynamic strain is not sensitive to the composition in the appropriate range.The effects of primary alpha volume fraction on the dynamic properties are dependent on the compositions of Ti–Al–V alloys.展开更多
The sintering of chromium-containing vanadium-titanium magnetite using different coke contents was studied through the sintering pot tests, X-ray diffraction analysis and mineralogical phase analysis. Results showed t...The sintering of chromium-containing vanadium-titanium magnetite using different coke contents was studied through the sintering pot tests, X-ray diffraction analysis and mineralogical phase analysis. Results showed that, as the coke content increased from 3.2% to 4.4%, the liquid phase and combustion zone thickness increased while the vertical sintering rate and ratio of sintered product decreased. In addition, the combustion ratio of exhaust gas also increased with increasing the coke content, indicating that combustion zone temperature also increased, and the excessive the coke content in the sintering process of vanadiumtitanium magnetite is harmful. As the coke content increased, the magnetite, silicates, and perovskite contents of the sintered ore increased while the contents of hematite and calcium ferrite of sintered ore decreased; drum strength decreased, and reduction degradation properties increased while reduction ability decreased. We found that the appropriate coke content for the sintering process is 3.6 wt%.展开更多
The influence of interstitial content on mechanical properties of a new type of near α titanium alloy(Ti-Zr-Mo-Nb-Sn) at cryogenic temperature was studied. The results show that interstitial content affects the mecha...The influence of interstitial content on mechanical properties of a new type of near α titanium alloy(Ti-Zr-Mo-Nb-Sn) at cryogenic temperature was studied. The results show that interstitial content affects the mechanical properties of the alloy at cryogenic temperature. Interstitial element atoms solving into lattice causes the increasing of degree of distortion,which limits the sliding and twinning of dislocations. Reducing interstitial content is beneficial to generation of dislocation sliding and deformation twins. With interstitial element content reducing,the impact toughness and the elongation of the alloy decrease rapidly while the strength decreases weakly. To obtain good over-all properties at cryogenic temperature,the interstitial element content in this alloy must be controlled to extra low grade.展开更多
The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring casting.After extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyz...The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring casting.After extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyzed compared with the ZX60(Mg-6Zn-0.2Ca)alloy.The results showed that the addition of Ti_(p) could not only promote the nucleation of dynamic recrystallized(DRXed)grains,but also be propitious to the refinement of DRXed grains.With increasing Ti_(p) content,the size of DRXed grains decreased accompanied with increasing volume fraction of DRXed grains.As the Ti_(p) content increased to 15 vol.%,the average size and volume fraction of DRXed grains reached to~0.32μm and 93.2%,respectively.Besides,both the strength and elongation were improved by the addition of Ti_(p).With increasing content of Ti_(p),a substantial increase in the strength was achieved with little change in the elongation.However,the elongation decreased sharply when the Ti_(p) content further increased to 15 vol.%.The addition of Ti_(p) led to an increase in the work hardening rate,which gradually increased with increasing Ti_(p) content.However,the softening rate did not demonstrate the same tendency with increasing Ti_(p) content.Unlike the conventional ceramic particles,the Ti_(p) can be deformed in coordination with the matrix alloy,which imparted a higher softening rate to the matrix alloy.Even though the softening rate improved as the Ti_(p) content increased from 5 to 10 vol.%,it dropped deeply as the Ti_(p) content increased to 15 vol.%owing to the fracture of Ti_(p) during extrusion.展开更多
Electron beam welding experiments of titanium alloys with different vanadium content to stainless steel,as well as alpha titanium to stainless steel using vanadium sheets as filler metal and transition portion were ca...Electron beam welding experiments of titanium alloys with different vanadium content to stainless steel,as well as alpha titanium to stainless steel using vanadium sheets as filler metal and transition portion were carried out.Microstructures of the joints were examined by scanning electron microscope.The properties were evaluated by microhardness and tensile strength.It was shown that electron beam welding is not feasible due to the brittle Ti-Fe intermetallics with high hardness.Increase of vanadium content in base metal can restrain but can't avoid the formation of cracks.When vanadium content was too large,the joint was embrittled by FeTi compound with supersaturated V and also cracked after welding.Crack free joint was achieved by using vanadium transition portion which can prevent the contact of Ti and Fe elements.However,the formation of brittle σ intermetallics reduced the tensile strength of the joint,only up to 134MPa.展开更多
To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentall...To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α stabilizing or β stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as cast samples. The content profiles of nitrogen and alloying elements around N containing solid in α Ti region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.展开更多
Metallic titanium film was deposited on H-13 steel substrate at 470°C - 530°C using plasma enhanced chemical vapor deposition (PECVD) method. In this paper, the effects of manufacturing parameters were inves...Metallic titanium film was deposited on H-13 steel substrate at 470°C - 530°C using plasma enhanced chemical vapor deposition (PECVD) method. In this paper, the effects of manufacturing parameters were investigated on deposited titanium coating characteristics. XRD, FESEM, XPS and AFM were used in order to study coating characteristics. Increasing hydrogen flow rate from 200 to 360 sccm, resulted in a 72% decrease in oxygen content and 38% decrease in chlorine content of the film. Applied plasma voltage has a severe effect on nanohardness of coating. Pressure of the deposition chamber has a negative effect on titanium characteristics.展开更多
采用氧含量分别为0.05%、0.10%、0.15%、0.20%、0.25%的5种TA2板材开展试验,对比分析氧含量对室温、150℃、200℃时TA2板材拉伸性能的影响。试验结果表明:随着氧含量的增加,TA2板材的抗拉强度和屈服强度大幅提升,伸长率逐步下降。在200...采用氧含量分别为0.05%、0.10%、0.15%、0.20%、0.25%的5种TA2板材开展试验,对比分析氧含量对室温、150℃、200℃时TA2板材拉伸性能的影响。试验结果表明:随着氧含量的增加,TA2板材的抗拉强度和屈服强度大幅提升,伸长率逐步下降。在200℃时,拉伸断口形貌均为等轴状的韧窝,并随着氧含量的增加,韧窝形貌由大而深逐渐变为小而浅。当氧含量为0.20%时,TA2板材在室温、150℃、200℃时的抗拉强度、屈服强度和伸长率可同时满足ASTM B 265-20规定的性能指标要求。展开更多
文摘On the basis of the thermodynamic analysis and fundamental study in the laboratory, the equilibrium of the Ti A10 system was investigated. The results showed that the equilibrium titanium content in the steel increased with the increase in the soluble aluminum content in the steel and the TiO2 content in the slag. Although the slag basicity decreased and Al2O3 content in the slag increased, the titanium content increased. Based on these results, the BOF smelting process of low titanium bearing steel was put forward.
文摘A series of Al based alloys with low titanium contents (mass fraction) from 0.178% to 0.526% were directly produced in ordinary industrial electrolyzer. The electrolyzing results show that producing Al based alloys with titanium contents of less than 0.30% without great loss of electrolysis efficiency is possible. The quantitative analysis shows that this method has a great refining effect on transiting the coarse columnar grains in pure Al to equiaxed grains. The grain sizes decrease with the increase of titanium content and tend to a low limit at about 130 μm. During the solidification, the non equilibrium distribution of titanium leads to a great growth restricting effect and a constitutional under cooling zone in front of the growing liquid /solid interface.
基金supported by the Research Foundation of Science and Technology, China University of Geosciences (Wuhan) (Grant No. CUGXGF0901),the Special Fund for Basic Scientific Research of Central Colleges, China University of Geosciences (Wuhan) (Grant No. CUGL090228)the National College Students Innovation Foundation of China (Grant No. 091049130)
文摘Two linear regression models based on absorption features extracted from CE-1 IIM image data are presented to discuss the relationship between absorption features and titanium content. We computed five absorption parameters (Full Wave at Half Maximum (FWHM), absorption position, absorption area, absorption depth and absorption asymmetry) of the spectra collected at Apollo 17 landing sites to build two regression models, one with FWHM and the other without FWHM due to the low relation coefficient between FWHM and Ti content. Finally Ti content measured from Apollo 17 samples and Apollo 16 samples was used to test the accuracy. The results show that the predicted values of the model with FWHM have many singular values and the result of model without FWHM is more stable. The two models are relatively accurate for high-Ti districts, while seem inexact and disable for low-Ti districts.
基金supported by the China–Korea Joint Research Program of Ministry of Science and Technology of China (No. 2012DFG51540)
文摘A series of Ti–Al–V titanium alloy bars with nominal composition Ti–7Al–5V ELI,Ti–5Al–3V ELI,commercial Ti–6Al–4V ELI and commercial Ti–6Al–4V were prepared.These alloys were then heat treated to obtain bimodal or equiaxed microstructures with various contents of primary a phase.Dynamic compression properties of the alloys above were studied by split Hopkinson pressure bar system at strain rates from 2,000 to 4,000 s-1.The results show that Ti–6Al–4V alloy with equiaxed primary a(ap)volume fraction of 45 vol%or 67 vol%exhibits good dynamic properties with high dynamic strength and absorbed energy,as well as an acceptable dynamic plasticity.However,all the Ti53ELI specimens and Ti64ELI specimens with ap of 65 vol%were not fractured at a strain rate of4,000 s-1.It appears that the undamaged specimens still have load-bearing capability.Dynamic strength of Ti–Al–V alloy can be improved as the contents of elements Al,V,Fe,and O increase,while dynamic strain is not sensitive to the composition in the appropriate range.The effects of primary alpha volume fraction on the dynamic properties are dependent on the compositions of Ti–Al–V alloys.
基金Funded by the National Natural Science Foundation of China(Nos.51604065,51674084)the Fundamental Funds for the Program of the Science Foundation of Liaoning Province(No.20170540316)
文摘The sintering of chromium-containing vanadium-titanium magnetite using different coke contents was studied through the sintering pot tests, X-ray diffraction analysis and mineralogical phase analysis. Results showed that, as the coke content increased from 3.2% to 4.4%, the liquid phase and combustion zone thickness increased while the vertical sintering rate and ratio of sintered product decreased. In addition, the combustion ratio of exhaust gas also increased with increasing the coke content, indicating that combustion zone temperature also increased, and the excessive the coke content in the sintering process of vanadiumtitanium magnetite is harmful. As the coke content increased, the magnetite, silicates, and perovskite contents of the sintered ore increased while the contents of hematite and calcium ferrite of sintered ore decreased; drum strength decreased, and reduction degradation properties increased while reduction ability decreased. We found that the appropriate coke content for the sintering process is 3.6 wt%.
基金Project(2007CB613807) supported by National Basic Research Program of China
文摘The influence of interstitial content on mechanical properties of a new type of near α titanium alloy(Ti-Zr-Mo-Nb-Sn) at cryogenic temperature was studied. The results show that interstitial content affects the mechanical properties of the alloy at cryogenic temperature. Interstitial element atoms solving into lattice causes the increasing of degree of distortion,which limits the sliding and twinning of dislocations. Reducing interstitial content is beneficial to generation of dislocation sliding and deformation twins. With interstitial element content reducing,the impact toughness and the elongation of the alloy decrease rapidly while the strength decreases weakly. To obtain good over-all properties at cryogenic temperature,the interstitial element content in this alloy must be controlled to extra low grade.
基金supported financially by the National Natural Science Foundation of China (Nos.52271109 and 52001223)the authors also thank the Support from the"the National Key Research and Development Program for Young Scientists" (No.2021YFB3703300)the Special Fund Project for Guiding Local Science and Technology Development by the Central Government (No.YDZJSX2021B019).
文摘The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring casting.After extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyzed compared with the ZX60(Mg-6Zn-0.2Ca)alloy.The results showed that the addition of Ti_(p) could not only promote the nucleation of dynamic recrystallized(DRXed)grains,but also be propitious to the refinement of DRXed grains.With increasing Ti_(p) content,the size of DRXed grains decreased accompanied with increasing volume fraction of DRXed grains.As the Ti_(p) content increased to 15 vol.%,the average size and volume fraction of DRXed grains reached to~0.32μm and 93.2%,respectively.Besides,both the strength and elongation were improved by the addition of Ti_(p).With increasing content of Ti_(p),a substantial increase in the strength was achieved with little change in the elongation.However,the elongation decreased sharply when the Ti_(p) content further increased to 15 vol.%.The addition of Ti_(p) led to an increase in the work hardening rate,which gradually increased with increasing Ti_(p) content.However,the softening rate did not demonstrate the same tendency with increasing Ti_(p) content.Unlike the conventional ceramic particles,the Ti_(p) can be deformed in coordination with the matrix alloy,which imparted a higher softening rate to the matrix alloy.Even though the softening rate improved as the Ti_(p) content increased from 5 to 10 vol.%,it dropped deeply as the Ti_(p) content increased to 15 vol.%owing to the fracture of Ti_(p) during extrusion.
文摘Electron beam welding experiments of titanium alloys with different vanadium content to stainless steel,as well as alpha titanium to stainless steel using vanadium sheets as filler metal and transition portion were carried out.Microstructures of the joints were examined by scanning electron microscope.The properties were evaluated by microhardness and tensile strength.It was shown that electron beam welding is not feasible due to the brittle Ti-Fe intermetallics with high hardness.Increase of vanadium content in base metal can restrain but can't avoid the formation of cracks.When vanadium content was too large,the joint was embrittled by FeTi compound with supersaturated V and also cracked after welding.Crack free joint was achieved by using vanadium transition portion which can prevent the contact of Ti and Fe elements.However,the formation of brittle σ intermetallics reduced the tensile strength of the joint,only up to 134MPa.
文摘To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α stabilizing or β stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as cast samples. The content profiles of nitrogen and alloying elements around N containing solid in α Ti region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.
文摘Metallic titanium film was deposited on H-13 steel substrate at 470°C - 530°C using plasma enhanced chemical vapor deposition (PECVD) method. In this paper, the effects of manufacturing parameters were investigated on deposited titanium coating characteristics. XRD, FESEM, XPS and AFM were used in order to study coating characteristics. Increasing hydrogen flow rate from 200 to 360 sccm, resulted in a 72% decrease in oxygen content and 38% decrease in chlorine content of the film. Applied plasma voltage has a severe effect on nanohardness of coating. Pressure of the deposition chamber has a negative effect on titanium characteristics.
文摘采用氧含量分别为0.05%、0.10%、0.15%、0.20%、0.25%的5种TA2板材开展试验,对比分析氧含量对室温、150℃、200℃时TA2板材拉伸性能的影响。试验结果表明:随着氧含量的增加,TA2板材的抗拉强度和屈服强度大幅提升,伸长率逐步下降。在200℃时,拉伸断口形貌均为等轴状的韧窝,并随着氧含量的增加,韧窝形貌由大而深逐渐变为小而浅。当氧含量为0.20%时,TA2板材在室温、150℃、200℃时的抗拉强度、屈服强度和伸长率可同时满足ASTM B 265-20规定的性能指标要求。
