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Effect of heating time on bonding interface, atom diffusion and mechanical properties of dissimilar titanium joints produced by thermal self-compressing bonding 被引量:7
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作者 Yun-hua DENG Qiao GUAN Jun TAO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第4期662-668,共7页
Solid-state bonding between pure titanium and Ti6Al4V(TC4)alloy was conducted by a new bonding method named as rigid restraint thermal self-compressing bonding.Effects of heating time on bonding interface,atom diffusi... Solid-state bonding between pure titanium and Ti6Al4V(TC4)alloy was conducted by a new bonding method named as rigid restraint thermal self-compressing bonding.Effects of heating time on bonding interface,atom diffusion and mechanical properties of the joints were studied.Results show that atom diffusion between pure titanium and TC4 alloy significantly takes place during bonding.The diffusion depths of Al and V in pure titanium side are increased with increasing heating time.Due to the enhancement of atom diffusion,bond quality of the bonding interface is improved along with the increase of heating time.The heating time seems to have little effect on microhardness distribution across the joint.However,the tensile strength and ductility of the joint have close relation to heating time.Prolonging heating time can improve the tensile strength and ductility of the joint,especially the latter.When the heating time increases to 450 s,solid-state joint with good combination of strength and ductility is attained. 展开更多
关键词 dissimilar titanium alloys joining rigid restraint thermal self-compressing bonding atom diffusion mechanical properties
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Effect of Back Diffusion of Mg Dopants on Optoelectronic Properties of InGaN-Based Green Light-Emitting Diodes
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作者 张宁 魏学成 +6 位作者 路坤熠 冯梁森 杨杰 薛斌 刘喆 李晋闽 王军喜 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第11期96-98,共3页
The effect of back-diffusion of Mg dopants on optoelectronic characteristics of InGaN-based green light-emitting diodes (LEDs) is investigated. The LEDs with less Mg back-diffusion show blue shifts of longer wavelen... The effect of back-diffusion of Mg dopants on optoelectronic characteristics of InGaN-based green light-emitting diodes (LEDs) is investigated. The LEDs with less Mg back-diffusion show blue shifts of longer wavelengths and larger wavelengths with the increasing current, which results from the Mg-dopant-related polarization screening. The LEDs show enhanced efficiency with the decreasing Mg back-diffusion in the lower current region. Light outputs follow the power law L α I^m, with smaller parameter m in the LEDs with less Mg back-diffusion, indicating a lower density of trap states. The trap-assisted tunneling current is also suppressed by reducing Mg- defect-related nonradiative centers in the active region. Furthermore, the forward current-voltage characteristics are improved. 展开更多
关键词 LEDs in it as InGaN Effect of Back diffusion of Mg Dopants on Optoelectronic Properties of InGaN-Based Green Light-Emitting Diodes of on
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Structure,room-temperature magnetic and optical properties of Mn-doped TiO_2 nano powders prepared by the sol-gel process
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作者 丁芃 刘发民 +4 位作者 周传仓 钟文武 张嬛 蔡鲁刚 曾乐贵 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期667-672,共6页
TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO... TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 ℃ are of pure anatase and rutile, respectively. The scanning electron microscope (SEM) observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy (HRTEM) investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron (BMP) theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 ℃ is stronger than that of the sample treated at 800 ℃. The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping. 展开更多
关键词 Mn-doped TiO2 nano powders sol-gel process room-temperature magnetic properties diffuse reflectance spectra
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Detailed Evolution Mechanism of Interfacial Void Morphology in Diffusion Bonding 被引量:6
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作者 Chao Zhang Hong Li Miaoquan Li 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第3期259-264,共6页
Similar diffusion bonding of 1Cr11Ni2W2MoV stainless steel was conducted at different bonding tem- peratures. The interface characteristics and mechanical properties of joints were examined, and the evolution of inter... Similar diffusion bonding of 1Cr11Ni2W2MoV stainless steel was conducted at different bonding tem- peratures. The interface characteristics and mechanical properties of joints were examined, and the evolution of interracial void morphology was analyzed in detail The results showed that there were four typical interfacial void shapes generating sequentially: the large scraggly voids, penny-shaped voids, ellipse voids and rounded voids. The variation of interracial void shape was dominated by surface diffusion, while the reduction of void volume was ascribed to the combined effects of plastic flow of materials around voids, interface diffusion and volume diffusion. Owing to the elimination of void from the bonding interface, the sound joint obtained could exhibit nearly full interracial contact, and present excellent mechanical properties, in which the microhardness and shear strength of joint matched those of base material. 展开更多
关键词 Stainless steel diffusion bonding Void morphology Mechanical property
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Diffusion and sound absorption properties of the quadratic residue diffuser structure with perforated panel 被引量:3
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作者 CAI Jun BAO Fei +1 位作者 WANG Yachen WANG Yanqin 《Chinese Journal of Acoustics》 CSCD 2016年第3期255-264,共10页
Acoustic structure study always is the academic research interest. Diffusion ab?sorbing structure(DiflFsorber) has good research value because it has both diflFusion property and sound absorption property. Quadrati... Acoustic structure study always is the academic research interest. Diffusion ab?sorbing structure(DiflFsorber) has good research value because it has both diflFusion property and sound absorption property. Quadratic residue diffusers(QRD) structure which had good diffusion property was combined with the perforated panel which had good sound absorption property in this study. According to standard AES-4id-2001, the diffusion experiments were carried out to study QRD structure and ones composited with perforated-panels which had1 mm-thickness and perforated percentage of 3%, 5%, 8% respectively. The polar coordinate diagrams of different structure were analyzed to derive the diffusion coefficients. Results showed that the composite structure still had good diffusion performance in the frequency range from100 Hz to 800 Hz. The reflection sound energy of composite structure reduced obviously in the perforated panel resonance frequency range where there was about 2 dB reduction averagely.The study result can provide the reference for the design and development of diifsorber. 展开更多
关键词 RATE diffusion and sound absorption properties of the quadratic residue diffuser structure with perforated panel
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