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Dynamic globularization kinetics during hot working of TA15 titanium alloy with colony microstructure 被引量:20
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作者 吴成宝 杨合 +1 位作者 樊晓光 孙志超 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第9期1963-1969,共7页
The dynamic globularization kinetics of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy with a colony α microstructure during deformation at temperature range of 860-940 ℃ and strain rate range of 0.01-10 s-1 was quantitat... The dynamic globularization kinetics of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy with a colony α microstructure during deformation at temperature range of 860-940 ℃ and strain rate range of 0.01-10 s-1 was quantitatively studied through isothermal compression tests.It is found that the dynamic globularization kinetics and the kinetics rate of TA15 are sensitive to deformation parameters.The dynamic globularized fraction increases with increasing strain,temperature but decreasing strain rate.The variation of globularized fraction with strain approximately follows an Avrami type equation.Using the Avrami type equation,the initiation and completion strains for dynamic globularization of TA15 were predicted to be 0.34-0.59 and 3.40-6.80.The kinetics rate of dynamic globularization increases with strain at first,then decreases.The peak value of kinetics rate,which corresponds to 20%-33% globularization fraction,increases with increasing temperature and decreasing strain rate. 展开更多
关键词 ta15 titanium alloy dynamic globularization KINETICS STRAIN kinetics rate
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Residual elastic stress strain field and geometrically necessary dislocation density distribution around nano-indentation in TA15 titanium alloy 被引量:7
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作者 何东 朱景川 +3 位作者 来忠红 刘勇 杨夏炜 农智升 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期7-13,共7页
Nanoindentation and high resolution electron backscatter diffraction(EBSD) were combined to examine the elastic modulus and hardness of α and β phases,anisotropy in residual elastic stress strain fields and distri... Nanoindentation and high resolution electron backscatter diffraction(EBSD) were combined to examine the elastic modulus and hardness of α and β phases,anisotropy in residual elastic stress strain fields and distributions of geometrically necessary dislocation(GND) density around the indentations within TA15 titanium alloy.The nano-indention tests were conducted on α and β phases,respectively.The residual stress strain fields surrounding the indentation were calculated through crosscorrelation method from recorded patterns.The GND density distribution around the indentation was calculated based on the strain gradient theories to reveal the micro-mechanism of plastic deformation.The results indicate that the elastic modulus and hardness for α p hase are 129.05 GPas and 6.44 GPa,while for β phase,their values are 109.80 GPa and 4.29 GPa,respectively.The residual Mises stress distribution around the indentation is relatively heterogeneous and significantly influenced by neighboring soft β phase.The region with low residual stress around the indentation is accompanied with markedly high a type and prismatic-GND density. 展开更多
关键词 nano-hardness stress strain fields geometrically necessary dislocation NANOINDENTATION electron backscatter diffraction ta15 titanium alloy
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Simulated and experimental investigation on discontinuous dynamic recrystallization of a near-α TA15 titanium alloy during isothermal hot compression in βsingle-phase field 被引量:5
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作者 武川 杨合 李宏伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1819-1829,共11页
A cellular automaton(CA) modeling of discontinuous dynamic recrystallization(DDRX) of a near-α Ti-6Al-2Zr-1Mo-1V(TA15) isothermally compressed in the β single phase field was presented.In the CA model,nucleati... A cellular automaton(CA) modeling of discontinuous dynamic recrystallization(DDRX) of a near-α Ti-6Al-2Zr-1Mo-1V(TA15) isothermally compressed in the β single phase field was presented.In the CA model,nucleation of the β-DDRX and the growth of recrystallized grains(re-grains) were considered and visibly simulated by the CA model.The driving force of re-grain growth was provided by dislocation density accumulating around the grain boundaries.To verify the CA model,the predicted flow stress by the CA model was compared with the experimental data.The comparison showed that the average relative errors were10.2%,10.1%and 6%,respectively,at 1.0,0.1 and 0.01 s^-1 of 1020 ℃,and were 10.2%,11.35%and 7.5%,respectively,at 1.0,0.1and 0.01 s^-1 of 1050 ℃.The CA model was further applied to predicting the average growth rate,average re-grain size and recrystallization kinetics.The simulated results showed that the average growth rate increases with the increasing strain rate or temperature,while the re-grain size increases with the decreasing strain rate;the volume fraction of recrystallization decreases with the increasing strain rate or decreasing temperature. 展开更多
关键词 discontinuous dynamic recrystallization cellular automaton dislocation density evolution recrystallization kinetics ta15 titanium alloy
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Deformation banding in β working of two-phase TA15 titanium alloy 被引量:3
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作者 Xiao-guang FAN Xiang ZENG +4 位作者 He YANG Peng-fei GAO Miao MENG Rui ZUO Peng-hui LEI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第11期2390-2399,共10页
To study deformation banding inβworking of TA15titanium alloy,hot simulation compression experiments were carried out on a Gleeble3500thermal simulator,and the microstructure was investigated by optical microscopy(OM... To study deformation banding inβworking of TA15titanium alloy,hot simulation compression experiments were carried out on a Gleeble3500thermal simulator,and the microstructure was investigated by optical microscopy(OM)and electron backscattered diffraction(EBSD).It is found that inβworking of TA15titanium alloy,deformation banding is still an important grain refinement mechanism up to temperature as high as0.7Tm(Tm is the melting temperature).Boundaries of deformation bands(DBBs)may be sharp or diffusive.Sharp DBBs retard discontinuous dynamic recrystallization(DDRX)by prohibiting nucleation,while the diffusive ones are sources of continuous dynamic recrystallization(CDRX).Deformation banding is more significant at high strain rate and large initial grain size.The average width of grain subdivisions is sensitive to strain rate but less affected by temperature and initial grain size.Multi-directional forging which produces crossing DDBs is potential to refine microstructure of small-size forgings. 展开更多
关键词 ta15 titanium alloy β working deformation banding grain refinement dynamic recrystallization
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Hot spinning of cylindrical workpieces of TA15 titanium alloy 被引量:1
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作者 XU Wenchen,SHAN Debin,YANG Guoping,CHEN Yu,LU Yan,and KANG Dachang School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China 《Rare Metals》 SCIE EI CAS CSCD 2007年第S1期255-261,共7页
In order to form large-diameter thin-wall cylindrical workpieces of TA15 titanium alloy,tube hot spinning experiments of the alloy were conducted on a CNC hot spinning machine.The causes of some forming defects occuri... In order to form large-diameter thin-wall cylindrical workpieces of TA15 titanium alloy,tube hot spinning experiments of the alloy were conducted on a CNC hot spinning machine.The causes of some forming defects occuring in hot spinning,such as crack,pileup,bulge and corrugation,were analyzed and the corresponding measures were put forward to avoid spinning defects,based on which a proper process scheme of hot spinning of TA15 alloy was obtained and the large-diameter and thin-walled cylindrical workpieces were formed with good quality.The results show that spinning temperature has distinct influence on forming quality of spun workpieces.The range of spinning temperature determines the spinnability of titanium alloy and the ununiformity of temperature distribution near the deformation zone leads to the formation of bulge.The reasonable heating method is that the deforming region is heated to the optimum temperature range of 600-700 ℃,the deformed region is heated continuously and a certain length of undeformed region is preheated.With the thickness-to-diameter ratio(t/D) of spun workpiece reducing to certain value(t/D<1%),surface bulge and corrugation is rather easier to come into being,which could be controlled through restraining diameter growth and employing smaller reduction rate and lower temperature in the optimum spinning temperature range. 展开更多
关键词 ta15 titanium alloy hot spinning cylindrical workpiece forming defect thickness-to-diameter ratio
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Microstructure and defect of titanium alloy electron beam deep penetration welded joint 被引量:8
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作者 张秉刚 石铭霄 +1 位作者 陈国庆 冯吉才 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第11期2633-2637,共5页
The microstructure, phase composition and cold shut defect of thick titanium alloy electron beam welded joint were studied. The results showed that the microstructure of weld zone was composed of α′ phase; the heat ... The microstructure, phase composition and cold shut defect of thick titanium alloy electron beam welded joint were studied. The results showed that the microstructure of weld zone was composed of α′ phase; the heat affected zone was divided into fine-grained zone and coarse-grained zone, the microstructure of fine-grained zone was primary α phase + β phase + equiaxed α phase, and the microstructure of coarse-grained zone was primary α phase + acicular α′ phase; the microstructure of base metal zone basically consisted of primary α phase, and a small amount of residual β phase sprinkled. The forming. reason of cold shut was analyzed, and the precaution of cold shut was proposed. 展开更多
关键词 ta15 titanium alloy electron beam welding MICROSTRUCTURE phase composition cold shut defect weld zone heataffected zone
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Morphology development of elongated α phases in hot working of large-scale titanium alloy plate 被引量:3
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作者 樊晓光 杨合 +1 位作者 高鹏飞 严思梁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3508-3516,共9页
The role of subtransus hot working on microstructure morphology of TA15 titanium alloy plate with elongatedαphases was studied by quantitative metallography on different sections. The results show that the microstruc... The role of subtransus hot working on microstructure morphology of TA15 titanium alloy plate with elongatedαphases was studied by quantitative metallography on different sections. The results show that the microstructure morphology is mainly affected by loading direction. When the sample is compressed along normal direction, microstructure on the section vertical to normal direction has equiaxed primaryαphase but microstructure on the section vertical to rolling direction has strip primaryαphase with long axis along tangential direction. When the sample is compressed along rolling direction, microstructure on the section vertical to normal direction has strip primaryαphase elongated along tangential direction but microstructure on the section vertical to rolling direction consists of strip and irregular broad-band primaryαphase. The strip primaryαphase aspect ratio is smaller at lower temperature due to the dynamic break-down ofαphase. The difference on primaryαphase aspect ratio between different sections decreases after compression along distinct directions in two loading passes, suggesting the improvement of equiaxity of primaryαphase. 展开更多
关键词 microstructure morphology ta15 titanium alloy elongatedαphases subtransus hot working
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Microstructures and microhardness for sheets and TIG welded joints of TA15 alloy using friction stir spot processing
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作者 Xia-wei YANG Wen-ya LI +4 位作者 Hong-yu LI Shuo-tian YAO Yi-xuan SUN Yi-xian SUN Lu MEI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第1期55-65,共11页
Effects of friction stir spot processing(FSSP)on the microstructures and microhardness of tungsten inert gas(TIG)welded TA15titanium alloy joints were investigated.The macro/micro structural observation and microhardn... Effects of friction stir spot processing(FSSP)on the microstructures and microhardness of tungsten inert gas(TIG)welded TA15titanium alloy joints were investigated.The macro/micro structural observation and microhardness evaluation of the TA15alloy sheets and TA15TIG welded joints were carried out using optical microscope and microhardness tests.The results show that FSSP effectively improves the microstructure and increases the microhardness of the TA15sheets.As for the TIG welded joints,FSSP also effectively improves the microstructure of joints.And the average microhardness value in weld nugget zone is improved significantly,while a small increase of this value in heat affected zone is observed.The hardness in stirring zone is significantly higher than that in the base metal.Two peak values of hardness appear along the width direction in stirring zone.After FSSP,the average hardness of the weld zone of TA15TIG welded joint is significantly higher than that before FSSP.Under the present process parameters,both the surface oxidation in TA15sheets and in TIG welded joints after FSSP are not evident,while the surface forms the bright white layer,which is composed of a great multitude of fine grains. 展开更多
关键词 friction stir spot processing ta15 titanium alloy TIG welded joint microstructure MICROHARDNESS
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Burning products of TA15 titanium alloy by friction oxygen concentration method 被引量:3
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作者 Nan Sui Guang-Bao Mi +2 位作者 Meng-Qi Yan Jing-Xia Cao Xu Huang 《Rare Metals》 SCIE EI CAS CSCD 2018年第11期952-960,共9页
The microstructural characteristics, elemental distribution law and microscopic formation mechanism of the burning products of TA15 titanium alloy were investigated by friction oxygen concentration method, associated ... The microstructural characteristics, elemental distribution law and microscopic formation mechanism of the burning products of TA15 titanium alloy were investigated by friction oxygen concentration method, associated with in situ observation, X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy-dispersive spectroscopy(EDS) analyses, providing the thoughts to improve fireproof property. The results show that, when the friction contact pressure(p) is 0.20 MPa and oxygen concentration of premixed air flow(c) is 60 vol%, TA15 titanium alloy produces violent sparks and presents dazzling white light during combustion. The generated products after burning are mainly TiOand small amount of AlOoxides. Four distinct zones form from the combustion surface to the alloy matrix, and they are in the sequence of combustion zone, fusion zone, heat-affected zone and transition zone. Further, combustion zone is composed of TiOand A1203 compounds, containing obvious cracks. In the fusion zone, discontinuous oxygenrich Al-based solid solution forms, and the elemental distribution has strong volatility. In the heat-affected zone,there are abundant of Ti-based solid solution and small amount of Al-and Mo-based solid solution. Transition zone is made of lamellar structure. Two technical approaches are given to prevent oxygen diffusion inside the reaction zone and reaction-affected zone. On the one hand,the content of Al is designed as the upper limit of alloy composition; on the other hand, fireproof coatings are deposited on the surface of the alloy. 展开更多
关键词 Friction oxygen concentration method ta15 titanium alloy Burning products Microstructure titanium fire
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Anodic dissolution mechanism of TA15 titanium alloy during counter-rotating electrochemical machining 被引量:3
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作者 CAO WenJian WANG DengYong +1 位作者 CUI GuoWei ZHU Di 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2022年第6期1253-1262,共10页
Counter-rotating electrochemical machining(CRECM)is a novel shaping method with advantages in processing revolving parts,especially engine casings.However,few researchers have studied the anodic behaviour of the count... Counter-rotating electrochemical machining(CRECM)is a novel shaping method with advantages in processing revolving parts,especially engine casings.However,few researchers have studied the anodic behaviour of the counter-rotating state.This paper aims to analyse the anode dissolution behaviour of TA15 and obtain desired surface qualities in CRECM.The anodic characteristics were measured by polarization and cyclic voltammetry curves,and the passive-trans passive behaviour of TA15 was revealed.The electrode surface structures at different stages were analysed using electrochemical impedance spectroscopy(EIS),and a quantitative dissolution model was established to illustrate the electrochemical dissolution and structural evolution of the revolving surfaces.A series of CRECM experiments were conducted,and three stages(pitting corrosion,pitting expansion,and smoothing)were detected according to the current signals.In the first stage,an oxide film with small pores was formed initially on the metal surface when exposed to air.This air-formed oxide film was broken down locally during the electrochemical reaction process,resulting in the occurrence of pitting.With the increase of electricity,the oxide layer became thinner,and the pitting areas expanded and began to connect with each other.In this stage,the surface quality was poor owing to the uneven material dissolution.When the amount of electricity approximately reached a constant,the oxide layer was completely removed,and a very thin salt film was generated at the metal-electrolyte interface.In this stage,the material was dissolved uniformly,and the surface was smooth without pitting corrosion.Based on the obtained results,anode workpieces with grid-like convex structures were fabricated using CRECM.Both the revolving surface and the sidewalls of the convex structures can be controlled from pitting to smoothness. 展开更多
关键词 counter-rotating electrochemical machining(CRECM) anode dissolution behaviour current signal quantitative model ta15 titanium alloy
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Quantitative analysis of microstructure evolution induced by temperature rise during(α+β) deformation of TA15 titanium alloy 被引量:2
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作者 Liang-Gang Guo Shuai Zhu +2 位作者 He Yang Xiao-Guang Fan Fu-Long Chen 《Rare Metals》 SCIE EI CAS CSCD 2016年第3期223-229,共7页
Temperature rise is a significant factor influencing microstructure during(α+β) deformation of TA15 titanium alloy.An experiment was designed to explore microstructure evolution induced by temperature rise due to... Temperature rise is a significant factor influencing microstructure during(α+β) deformation of TA15 titanium alloy.An experiment was designed to explore microstructure evolution induced by temperature rise due to deformation heat.The experiment was carried out in(α+β) phase field at typical temperature rise rates.The microstructures of the alloy under different temperature rise rates were observed by scanning electron microscopy(SEM).It is found that the dissolution rate of primary equiaxed a phase increases with the increase in both temperature and temperature rise rate.In the same temperature range,the higher the temperature rise rate is,the larger the final content and grain size of primary equiaxed a phase are due to less dissolution time.To quantitatively depict the evolution behavior of primary equiaxed a phase under any temperature rise rates,the dissolution kinetics of primary equiaxed a phase were well described by a diffusion model.The model predictions,including content and grain size of primary equiaxed a phase,are in good agreement with experimental observations.The work provides an important basis for the prediction and control of microstructure during hot working of titanium alloy. 展开更多
关键词 ta15 titanium alloy Temperature rise Deformation heat Microstructure evolution model
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