Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 h...Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.展开更多
The reaction between high purity nickel (99.999%) and high purity tin (99.999%) was investigated in the temperature range of 232℃ - 330℃, at short periods of annealing (1 - 60 s). The reaction kinetic was studied us...The reaction between high purity nickel (99.999%) and high purity tin (99.999%) was investigated in the temperature range of 232℃ - 330℃, at short periods of annealing (1 - 60 s). The reaction kinetic was studied using cross-sectional scanning electron microscope (SEM) images. The intermetallic compound (IMC) growth was analyzed using the empirical power law and a time dependence in the range of 0.26 to 0.33 was found. The morphology of the IMC was investigated by SEM in the temperature range of 235℃ - 290℃, at annealing periods of 10 s, 30 s, and 60 s by selectively etching away the remaining elementary tin. The exposed IMC displays a change in morphology with increasing annealing temperature, demonstrating that the growth velocity of certain crystallographic orientations of the IMC is strongly influenced by the annealing temperature. Additionally, coarsening and crumbling of the IMC grains is observed, and will be discussed with respect to the responsible mechanisms.展开更多
Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still rare.Herein,we report the epitaxi...Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still rare.Herein,we report the epitaxial growth of quasi-two-dimensional(Q-2D)perovskites on methylammonium lead iodide(MAPbI_(3))single crystals to form perovskite heterojunctions with interfacial bonding.The MAPbI_(3)adjacent to epitaxial Q-2D perovskite shows blue shifted photoluminescence with shortened lifetime,which becomes significant with the reduced layer number of the Q-2D perovskites.Our findings suggest the presence of an interfacial strain gradient leading to enhanced photocarrier separation.Accordingly,compared to the MAPbI_(3)single crystal detector,the BA_(2)MAPb_(2)I_(7)/MAPbI_(3)(BA:n-butylamine)heterojunction-based photodetector demonstrates a bandpass detecting property and exhibits 5 times enhanced external quantum efficiency and 83 times enhanced specific detectivity(D*=3.26×10^(11)Jones).Remarkably,the unencapsulated BA_(2)MAPb_(2)I_(7)/MAPbI_(3)heterojunction is stable in ambient condition for>300 days.The Q-2D/3D heterojunction shows suppressed ion inter-diffusion due to the presence of Q-2D phase.展开更多
γ’+β Binary-phase Ni-Al coatings were prepared on second-generation single-crystal superalloy Rene N5(N5) substrates by electron beam physical vapor deposition.Inter-diffusion behavior between coatings and substrat...γ’+β Binary-phase Ni-Al coatings were prepared on second-generation single-crystal superalloy Rene N5(N5) substrates by electron beam physical vapor deposition.Inter-diffusion behavior between coatings and substrates at 1100℃ and its effects on microstructure stability of the substrates were investigated.A 3-μm-thick substrate diffusion zone(SDZ) layer forms beneath the coating/substrate interface after 5-h heat treatment.The SDZ layer is composed of γ’-Ni_(3) Al phases and needle-like precipitates growing along(100)(110) or(100) <■> direction.After100-h annealing,the thickness of the SDZ layer increases to~17 μm,much lower than that of the single β-NiAl-coated substrate,while keeping single-crystal microstructure.展开更多
基金This work was financially supported by National Nature Science Foundation of China (No.50075026)and Education Ministry of China (No.[2000]65)and research funding from Guangdong Provincial High Education Department (Thousand, Hundred Ten Project).]
文摘Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.
文摘The reaction between high purity nickel (99.999%) and high purity tin (99.999%) was investigated in the temperature range of 232℃ - 330℃, at short periods of annealing (1 - 60 s). The reaction kinetic was studied using cross-sectional scanning electron microscope (SEM) images. The intermetallic compound (IMC) growth was analyzed using the empirical power law and a time dependence in the range of 0.26 to 0.33 was found. The morphology of the IMC was investigated by SEM in the temperature range of 235℃ - 290℃, at annealing periods of 10 s, 30 s, and 60 s by selectively etching away the remaining elementary tin. The exposed IMC displays a change in morphology with increasing annealing temperature, demonstrating that the growth velocity of certain crystallographic orientations of the IMC is strongly influenced by the annealing temperature. Additionally, coarsening and crumbling of the IMC grains is observed, and will be discussed with respect to the responsible mechanisms.
基金the National Natural Science Foundation of China(Nos.52273202,62104261,51673218,and 62004066)the National Key Research and Development Program of China(No.2022YFB3803300)+4 种基金the Natural Science Program of Xinjiang Uygur Autonomous Region(No.2023D01D03)the Major Scientific and Technological Project of Changsha(No.kq2301002)the Program of Hundreds of Talents of Hunan Province and Changsha Municipal Natural Science Foundation(No.KQ2007027)the National Key Research and Development Program of China(No.2023YFE0116800)the Beijing Natural Science Foundation(No.IS23037).
文摘Although numerous metal halide perovskite materials have been investigated in the field of optoelectronic,the development of perovskite heterojunctions with exotic structures is still rare.Herein,we report the epitaxial growth of quasi-two-dimensional(Q-2D)perovskites on methylammonium lead iodide(MAPbI_(3))single crystals to form perovskite heterojunctions with interfacial bonding.The MAPbI_(3)adjacent to epitaxial Q-2D perovskite shows blue shifted photoluminescence with shortened lifetime,which becomes significant with the reduced layer number of the Q-2D perovskites.Our findings suggest the presence of an interfacial strain gradient leading to enhanced photocarrier separation.Accordingly,compared to the MAPbI_(3)single crystal detector,the BA_(2)MAPb_(2)I_(7)/MAPbI_(3)(BA:n-butylamine)heterojunction-based photodetector demonstrates a bandpass detecting property and exhibits 5 times enhanced external quantum efficiency and 83 times enhanced specific detectivity(D*=3.26×10^(11)Jones).Remarkably,the unencapsulated BA_(2)MAPb_(2)I_(7)/MAPbI_(3)heterojunction is stable in ambient condition for>300 days.The Q-2D/3D heterojunction shows suppressed ion inter-diffusion due to the presence of Q-2D phase.
基金financially supported by the National Natural Science Foundation of China(Nos.51590894,51425102 and 51231001)。
文摘γ’+β Binary-phase Ni-Al coatings were prepared on second-generation single-crystal superalloy Rene N5(N5) substrates by electron beam physical vapor deposition.Inter-diffusion behavior between coatings and substrates at 1100℃ and its effects on microstructure stability of the substrates were investigated.A 3-μm-thick substrate diffusion zone(SDZ) layer forms beneath the coating/substrate interface after 5-h heat treatment.The SDZ layer is composed of γ’-Ni_(3) Al phases and needle-like precipitates growing along(100)(110) or(100) <■> direction.After100-h annealing,the thickness of the SDZ layer increases to~17 μm,much lower than that of the single β-NiAl-coated substrate,while keeping single-crystal microstructure.
