Beta Ti−35Nb sandwich-structured composites with various reinforcing layers were designed and produced using additive manufacturing(AM)to achieve a balance between light weight and high strength.The impact of reinforc...Beta Ti−35Nb sandwich-structured composites with various reinforcing layers were designed and produced using additive manufacturing(AM)to achieve a balance between light weight and high strength.The impact of reinforcing layers on the compressive deformation behavior of porous composites was investigated through micro-computed tomography(Micro-CT)and finite element method(FEM)analyses.The results indicate that the addition of reinforcement layers to sandwich structures can significantly enhance the compressive yield strength and energy absorption capacity of porous metal structures;Micro-CT in-situ observation shows that the strain of the porous structure without the reinforcing layer is concentrated in the middle region,while the strain of the porous structure with the reinforcing layer is uniformly distributed;FEM analysis reveals that the reinforcing layers can alter stress distribution and reduce stress concentration,thereby promoting uniform deformation of the porous structure.The addition of reinforcing layer increases the compressive yield strength of sandwich-structured composite materials by 124%under the condition of limited reduction of porosity,and the yield strength increases from 4.6 to 10.3 MPa.展开更多
Ti-2 Al-9.2 Mo-2 Fe is a low-cost β titanium alloy with well-balanced strength and ductility, but hot working of this alloy is complex and unfamiliar. Understanding the nonlinear relationships among the strain,strain...Ti-2 Al-9.2 Mo-2 Fe is a low-cost β titanium alloy with well-balanced strength and ductility, but hot working of this alloy is complex and unfamiliar. Understanding the nonlinear relationships among the strain,strain rate, temperature, and flow stress of this alloy is essential to optimize the hot working process.In this study, a deep neural network(DNN) model was developed to correlate flow stress with a wide range of strains(0.025–0.6), strain rates(0.01–10 s^-1) and temperatures(750–1000℃). The model, which was tested with 96 unseen datasets, showed better performance than existing models, with a correlation coefficient of 0.999. The processing map constructed using the DNN model was effective in predicting the microstructural evolution of the alloy. Moreover, it led to the optimization of hot-working conditions to avoid the formation of brittle precipitates(temperatures of 820–1000℃ and strain rates of 0.01-0.1 s^-1).展开更多
The development of microstructure during the aging of Ti-10V-2Fe-3A1 alloy in the 13 and （α＋β） solution-treated and quenched conditions was investigated. The results showed that the isothermal holding below 400℃...The development of microstructure during the aging of Ti-10V-2Fe-3A1 alloy in the 13 and （α＋β） solution-treated and quenched conditions was investigated. The results showed that the isothermal holding below 400℃ yielded homogeneously distributed, spherical ω-phase particles. Fine α aggregates are formed uniformly within 13 grains by nucleating at at particles or β/ω interfaces. At higher temperatures, thin martensite plates decomposed in water-quenched condition. The formation of ω phase was avoided and coarse coarse α-phase plates directly precipitated from the 13 matrix. The highest hardness values were found when the alloys were aged at 400℃ for 8 h. The significance of the observations was discussed in terms of the effect of aging on the precipitations and property.展开更多
A new metastable beta titanium alloy of Ti-Al-Mo-V-Cr-Fe-Zr-Sn system was designed and named Ti-B20. In order to investigate the aging properties and microstructures of the new alloy subjected to different solution tr...A new metastable beta titanium alloy of Ti-Al-Mo-V-Cr-Fe-Zr-Sn system was designed and named Ti-B20. In order to investigate the aging properties and microstructures of the new alloy subjected to different solution treatments, the tensile and Vickers hardness tests were carried out and the optical microscope and scanning electron microscope analysis were performed. The results show that the new alloy displays rapid aging response, high age strengthening effect and fine deposition. In addition, beta solution results in ultra high age hardening effect with low tensile ductility, whereas excellent combination of aging strength and ductility can be obtained after solution treated below beta transus temperature.展开更多
Titanium and its alloys possess excellent comprehensive properties, and they are widely used in many fields. China pays great attentions to the research on new titanium alloys. This paper mainly reviews the research o...Titanium and its alloys possess excellent comprehensive properties, and they are widely used in many fields. China pays great attentions to the research on new titanium alloys. This paper mainly reviews the research on new Ti alloys in China, for example, high strength and high toughness Ti alloys, burn resistant Ti alloys, high temperature Ti alloys, low cost Ti alloys and so on. New basic theories on Ti alloys developed in China in recent years are also reviewed.展开更多
基金the Hunan Young Scientific Innovative Talents Program,China(No.2020RC3040)Outstanding Youth Fund of Hunan Natural Science Foundation,China(Nos.2021JJ20011,2021JJ40600,2021JJ40590)the National Natural Science Foundation of China(Nos.52001030,52204371)..
文摘Beta Ti−35Nb sandwich-structured composites with various reinforcing layers were designed and produced using additive manufacturing(AM)to achieve a balance between light weight and high strength.The impact of reinforcing layers on the compressive deformation behavior of porous composites was investigated through micro-computed tomography(Micro-CT)and finite element method(FEM)analyses.The results indicate that the addition of reinforcement layers to sandwich structures can significantly enhance the compressive yield strength and energy absorption capacity of porous metal structures;Micro-CT in-situ observation shows that the strain of the porous structure without the reinforcing layer is concentrated in the middle region,while the strain of the porous structure with the reinforcing layer is uniformly distributed;FEM analysis reveals that the reinforcing layers can alter stress distribution and reduce stress concentration,thereby promoting uniform deformation of the porous structure.The addition of reinforcing layer increases the compressive yield strength of sandwich-structured composite materials by 124%under the condition of limited reduction of porosity,and the yield strength increases from 4.6 to 10.3 MPa.
基金supported by grants from the Civil–Military Technology Cooperation Program (16-CM-MA-10) of the Defense Acquisition Program Administrationfrom the Core Material Program (10062485) of the Ministry of Trade, Industry and Energy, Republic of Korea
文摘Ti-2 Al-9.2 Mo-2 Fe is a low-cost β titanium alloy with well-balanced strength and ductility, but hot working of this alloy is complex and unfamiliar. Understanding the nonlinear relationships among the strain,strain rate, temperature, and flow stress of this alloy is essential to optimize the hot working process.In this study, a deep neural network(DNN) model was developed to correlate flow stress with a wide range of strains(0.025–0.6), strain rates(0.01–10 s^-1) and temperatures(750–1000℃). The model, which was tested with 96 unseen datasets, showed better performance than existing models, with a correlation coefficient of 0.999. The processing map constructed using the DNN model was effective in predicting the microstructural evolution of the alloy. Moreover, it led to the optimization of hot-working conditions to avoid the formation of brittle precipitates(temperatures of 820–1000℃ and strain rates of 0.01-0.1 s^-1).
文摘The development of microstructure during the aging of Ti-10V-2Fe-3A1 alloy in the 13 and （α＋β） solution-treated and quenched conditions was investigated. The results showed that the isothermal holding below 400℃ yielded homogeneously distributed, spherical ω-phase particles. Fine α aggregates are formed uniformly within 13 grains by nucleating at at particles or β/ω interfaces. At higher temperatures, thin martensite plates decomposed in water-quenched condition. The formation of ω phase was avoided and coarse coarse α-phase plates directly precipitated from the 13 matrix. The highest hardness values were found when the alloys were aged at 400℃ for 8 h. The significance of the observations was discussed in terms of the effect of aging on the precipitations and property.
文摘A new metastable beta titanium alloy of Ti-Al-Mo-V-Cr-Fe-Zr-Sn system was designed and named Ti-B20. In order to investigate the aging properties and microstructures of the new alloy subjected to different solution treatments, the tensile and Vickers hardness tests were carried out and the optical microscope and scanning electron microscope analysis were performed. The results show that the new alloy displays rapid aging response, high age strengthening effect and fine deposition. In addition, beta solution results in ultra high age hardening effect with low tensile ductility, whereas excellent combination of aging strength and ductility can be obtained after solution treated below beta transus temperature.
文摘Titanium and its alloys possess excellent comprehensive properties, and they are widely used in many fields. China pays great attentions to the research on new titanium alloys. This paper mainly reviews the research on new Ti alloys in China, for example, high strength and high toughness Ti alloys, burn resistant Ti alloys, high temperature Ti alloys, low cost Ti alloys and so on. New basic theories on Ti alloys developed in China in recent years are also reviewed.
