Flow behaviors of spray forming low solvus high refractory (LSHR) alloy were investigated using hot compression tests performed on a Gleeble?3500 thermal mechanical simulator at temperatures of 1020?1150 °C and s...Flow behaviors of spray forming low solvus high refractory (LSHR) alloy were investigated using hot compression tests performed on a Gleeble?3500 thermal mechanical simulator at temperatures of 1020?1150 °C and strain rates of 0.0003?1.0 s?1. The constitutive equation was established, power dissipation (η) maps and hot processing maps were plotted. The microstructure evolution and dislocation distribution of domains with different values of η in power dissipation maps were also observed. The results show that the flow stress increases with decreasing temperature and increasing strain rate. The activation energy of the spray forming LSHR alloy is 1243.86 kJ/mol. When the value of η is 0.36 at the strain of 0.5, the domain in the processing map shows characteristics of typical dynamic recrystallization (DRX) and low dislocation density. According to the microstructure evolution and processing maps, the optimum processing condition for good hot workability of spray forming LSHR alloy can be summed up as:temperature range 1110?1150 °C; strain rate range 0.01?0.3 s?1.展开更多
Low melting point metals（Ga, In, Sn） as alloy elements were used to prepare Al-In-Sn and Al-Ga-In-Sn alloys through mechanical ball milling method. The effects of mass ratio of In to Sn and Ga content on the hydroly...Low melting point metals（Ga, In, Sn） as alloy elements were used to prepare Al-In-Sn and Al-Ga-In-Sn alloys through mechanical ball milling method. The effects of mass ratio of In to Sn and Ga content on the hydrolysis properties of aluminum alloys were investigated. X-ray diffraction（XRD） and scanning electron microscopy（SEM） with energy disperse spectroscopy（EDS） were used to analyze the compositions and morphologies of the obtained Al alloys. The results show that the phase compositions of Al-In-Sn ternary alloys are Al and two intermetallic compounds, In3 Sn and In Sn4. All Al-In-Sn ternary alloys exhibit poor hydrolysis activity at room temperature. Al-In-Sn alloy with the mass ratio of In to Sn equaling 1：4 has the highest hydrogen yield. After Ga is introduced to the ternary alloys, the hydrolysis activity of aluminum alloys at room temperature is greatly improved. It is speculated that the addition of Ga element promotes the formation of defects inside the Al alloys and Ga-In3Sn-In Sn4 eutectic alloys on the alloys surface. Al atoms can be dissolved in this eutectic phase and become the active spots during the hydrolysis process. The small size and uniform distribution of this eutectic phase may be responsible for the enhancement of hydrolysis activity.展开更多
Low cycle fatigue （LCF） behavior of laser melting deposited （LMD） TC18 titanium alloy was studied at room temperature. Microstructure consisting of fine lamella-like primary α phase and transformed β matrix was ...Low cycle fatigue （LCF） behavior of laser melting deposited （LMD） TC18 titanium alloy was studied at room temperature. Microstructure consisting of fine lamella-like primary α phase and transformed β matrix was obtained by double annealed treatment, and inhomogeneous grain boundaryαphase was detected. Fatigue fracture surfaces and longitudinal sections of LCF specimens were examined by optical microscopy and scanning electron microscopy. Results indicate that more than one crack initiation site can be detected on the LCF fracture surface. The fracture morphology of the secondary crack initiation site is different from that of the primary crack initiation site. When the crack grows along the grain boundaryαphase, continuous grain boundaryαphase leads to a straight propagating manner while discontinuous grain boundaryαphase gives rise to flexural propagating mode.展开更多
The currently available 3D printing still cannot simultaneously deal with the metal and nonmetal inks together due to their huge difference in the melting points and poor compatible printability between each other. He...The currently available 3D printing still cannot simultaneously deal with the metal and nonmetal inks together due to their huge difference in the melting points and poor compatible printability between each other. Here through introducing the low melting point alloy Bi35In48.6Sn16Zno.4 and silicone rubber as functional inks, we proposed a compatible hybrid 3D printing method for manufacturing the desired device, the supporting substrate and the allied package structure together. The principle of pneumatic-typed 3D printing of multiple inks was described and typical physical properties of the ink Bi35In48.6Sn16Zno.4 were measured. Several key factors dominating the printing quality such as the temperature of the printing head, the air pressure exerted upon the liquid metal ink in the syringe, the moving velocity and the height of the printing head etc. were clarified. A general way of directly printing out 3D structured electronic devices consisting of both metal and nonmetal materials was demonstrated. Such hybrid objects were patterned and formed up layer by layer with Bi35In48.6Sn16Zno.4 alloy and silicone rub- ber which would become solidified after standing for a period of time under room temperature. To illustrate the compatible printability of these printing inks, a three-layer tricolor LED stereo circuit with controlled lighting capability was further man- ufactured and evaluated. The present study opens an important hybrid 3D printing way for directly manufacturing functional and structural end devices in an easy and low cost way.展开更多
Conventional 3D metal printings are generally time-consuming as well as lacking of high performance printable inks.From an alternative way,here we proposed the method of liquid phase 3D printing for quickly making con...Conventional 3D metal printings are generally time-consuming as well as lacking of high performance printable inks.From an alternative way,here we proposed the method of liquid phase 3D printing for quickly making conductive metal objects.Through introducing metal alloys whose melting point is slightly above room temperature as printing inks,several representative structures spanning from one,two and three dimension to more complex patterns were demonstrated to be quickly fabricated.Compared with the air-cooling in a conventional 3D printing,the liquid-phase-manufacturing offers a much higher cooling rate and thus significantly improves the speed in fabricating the target metal objects.This unique strategy also efficiently prevents the liquid metal inks from air oxidation,which is hard to avoid otherwise in an ordinary 3D printing.The key physical factors(such as properties of the cooling fluid,air pressure within the syringe barrel and needle diameter,types and properties of the printing ink)and several interesting intermediate fluids interaction phenomena between liquid metal and conventional cooling fluids such as water or ethanol,which evidently affecting the printing quality,were disclosed.In addition,a basic route to make future liquid phase 3D printer incorporated with both syringe pump and needle arrays was also suggested.The liquid phase 3D printing,which owns potential values not available in a conventional method,opens an efficient way for quickly making conductive metal objects in the coming time.展开更多
文摘制约可控核聚变堆商业化运用的关键问题之一是面向等离子体材料(plasma facing materials,PFMs),难熔多主元合金因其高温高强度、高熔点及良好的耐辐照性有望满足PFMs的需求。本工作设计并采用电弧熔炼制备了(TiVTa)_(95)X_(5)(X=Cr,Zr,W)低活化多主元合金,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及能量色散X射线谱仪(EDS)研究了Cr,Zr和W的添加对铸态、匀质TiVTa系合金的微观结构及900℃下相稳定性的影响。结果表明,铸态合金均为具有体心立方(BCC)结构的简单固溶体,经1200℃匀质化处理后(TiVTa)_(95)Cr_(5)合金发生相分解,基体内出现少量C15_Laves第二相。900℃下TiVTa系合金相稳定性不佳,均分解为一个BCC主相和沿晶界分布的C15_Laves第二相,TiVTa和(TiVTa)95 W 5合金中第二相体积分数较小,Cr,Zr的添加加剧相分解。经相结构及元素分析发现,(TiVTa)_(95)X_(5)(X=Cr,Zr,W)合金中析出的C15_Laves相晶格常数及元素组成均与二元合金体系中可能存在的Laves相不一致,差异主要来源于Laves相的元素组成。
基金Project(51301143)supported by the National Natural Science Foundation of ChinaProject(2014M560727)supported by the National Postdoctoral Foundation of China+1 种基金Project(2015GZ0228)supported by the Sichuan Province Science-Technology Support Plan,ChinaProject(2682014CX001)supported by the Science and Technology Innovation Project of SWJTU University,China
文摘Flow behaviors of spray forming low solvus high refractory (LSHR) alloy were investigated using hot compression tests performed on a Gleeble?3500 thermal mechanical simulator at temperatures of 1020?1150 °C and strain rates of 0.0003?1.0 s?1. The constitutive equation was established, power dissipation (η) maps and hot processing maps were plotted. The microstructure evolution and dislocation distribution of domains with different values of η in power dissipation maps were also observed. The results show that the flow stress increases with decreasing temperature and increasing strain rate. The activation energy of the spray forming LSHR alloy is 1243.86 kJ/mol. When the value of η is 0.36 at the strain of 0.5, the domain in the processing map shows characteristics of typical dynamic recrystallization (DRX) and low dislocation density. According to the microstructure evolution and processing maps, the optimum processing condition for good hot workability of spray forming LSHR alloy can be summed up as:temperature range 1110?1150 °C; strain rate range 0.01?0.3 s?1.
基金Project(2010CB635107) supported by the Major State Basic Research Development Program of ChinaProjects(51202064,51472081) supported by the National Natural Science Foundation of China+2 种基金Project(2013CFA085) supported by the Natural Science Foundation of Hubei Province,ChinaProject(2013070104010016) supported by Wuhan Youth Chenguang Program of Science and Technology,ChinaProject([2013]2-22) supported by the Open Fund of Key Laboratory of Green Materials for Light Industry of Hubei Province,China
文摘Low melting point metals（Ga, In, Sn） as alloy elements were used to prepare Al-In-Sn and Al-Ga-In-Sn alloys through mechanical ball milling method. The effects of mass ratio of In to Sn and Ga content on the hydrolysis properties of aluminum alloys were investigated. X-ray diffraction（XRD） and scanning electron microscopy（SEM） with energy disperse spectroscopy（EDS） were used to analyze the compositions and morphologies of the obtained Al alloys. The results show that the phase compositions of Al-In-Sn ternary alloys are Al and two intermetallic compounds, In3 Sn and In Sn4. All Al-In-Sn ternary alloys exhibit poor hydrolysis activity at room temperature. Al-In-Sn alloy with the mass ratio of In to Sn equaling 1：4 has the highest hydrogen yield. After Ga is introduced to the ternary alloys, the hydrolysis activity of aluminum alloys at room temperature is greatly improved. It is speculated that the addition of Ga element promotes the formation of defects inside the Al alloys and Ga-In3Sn-In Sn4 eutectic alloys on the alloys surface. Al atoms can be dissolved in this eutectic phase and become the active spots during the hydrolysis process. The small size and uniform distribution of this eutectic phase may be responsible for the enhancement of hydrolysis activity.
基金Project(2011CB606305)supported by the National Basic Research Program of ChinaProject(IRT0805)supported by the Cheung Kong Scholars Innovation Research Team Program of Ministry of Education,China
文摘Low cycle fatigue （LCF） behavior of laser melting deposited （LMD） TC18 titanium alloy was studied at room temperature. Microstructure consisting of fine lamella-like primary α phase and transformed β matrix was obtained by double annealed treatment, and inhomogeneous grain boundaryαphase was detected. Fatigue fracture surfaces and longitudinal sections of LCF specimens were examined by optical microscopy and scanning electron microscopy. Results indicate that more than one crack initiation site can be detected on the LCF fracture surface. The fracture morphology of the secondary crack initiation site is different from that of the primary crack initiation site. When the crack grows along the grain boundaryαphase, continuous grain boundaryαphase leads to a straight propagating manner while discontinuous grain boundaryαphase gives rise to flexural propagating mode.
基金supported by the Research Funding of the Chinese Academy of Sciences(Grant No.KGZD-EW-T04-4)
文摘The currently available 3D printing still cannot simultaneously deal with the metal and nonmetal inks together due to their huge difference in the melting points and poor compatible printability between each other. Here through introducing the low melting point alloy Bi35In48.6Sn16Zno.4 and silicone rubber as functional inks, we proposed a compatible hybrid 3D printing method for manufacturing the desired device, the supporting substrate and the allied package structure together. The principle of pneumatic-typed 3D printing of multiple inks was described and typical physical properties of the ink Bi35In48.6Sn16Zno.4 were measured. Several key factors dominating the printing quality such as the temperature of the printing head, the air pressure exerted upon the liquid metal ink in the syringe, the moving velocity and the height of the printing head etc. were clarified. A general way of directly printing out 3D structured electronic devices consisting of both metal and nonmetal materials was demonstrated. Such hybrid objects were patterned and formed up layer by layer with Bi35In48.6Sn16Zno.4 alloy and silicone rub- ber which would become solidified after standing for a period of time under room temperature. To illustrate the compatible printability of these printing inks, a three-layer tricolor LED stereo circuit with controlled lighting capability was further man- ufactured and evaluated. The present study opens an important hybrid 3D printing way for directly manufacturing functional and structural end devices in an easy and low cost way.
基金supported by the Key Research Program of the Chinese Academy of Sciences(Grant No.KGZD-EW-T04)
文摘Conventional 3D metal printings are generally time-consuming as well as lacking of high performance printable inks.From an alternative way,here we proposed the method of liquid phase 3D printing for quickly making conductive metal objects.Through introducing metal alloys whose melting point is slightly above room temperature as printing inks,several representative structures spanning from one,two and three dimension to more complex patterns were demonstrated to be quickly fabricated.Compared with the air-cooling in a conventional 3D printing,the liquid-phase-manufacturing offers a much higher cooling rate and thus significantly improves the speed in fabricating the target metal objects.This unique strategy also efficiently prevents the liquid metal inks from air oxidation,which is hard to avoid otherwise in an ordinary 3D printing.The key physical factors(such as properties of the cooling fluid,air pressure within the syringe barrel and needle diameter,types and properties of the printing ink)and several interesting intermediate fluids interaction phenomena between liquid metal and conventional cooling fluids such as water or ethanol,which evidently affecting the printing quality,were disclosed.In addition,a basic route to make future liquid phase 3D printer incorporated with both syringe pump and needle arrays was also suggested.The liquid phase 3D printing,which owns potential values not available in a conventional method,opens an efficient way for quickly making conductive metal objects in the coming time.
