- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Radiation hardness and post irradiation regeneration behavior of GaInAsP solar cells
摘要： Recent developments have renewed the demand for solar cells with increased tolerance to radiation damage. To investigate the specific irradiation damage of 1 MeV electron irradiation in GaInAsP lattice matched to InP for varying In and P contents, a simulation based analysis is employed: by fitting the quantum efficiency and open-circuit voltage simultaneously before and after irradiation, the induced changes in lifetime are detected. Furthermore, the reduction of irradiation damage during regeneration under typical satellite operating conditions for GEO missions (60°C and AM0 illumination) is investigated. A clear decrease of the radiation damage is observed after post irradiation regeneration. This regeneration effect is stronger for increasing InP-fraction. It is demonstrated that the irradiation induced defect recombination coefficient for irradiation with 1 MeV electrons after regeneration for 216 h can be described with a linear function of InP-fraction between 1?10?5 cm2/s for GaAs and 7?10?7 cm2/s for InP. The results show that GaInAsP is a promising material for radiation hard space solar cells.
关键词： Radiation hardness,Annealing,MOVPE,GaInAsP,Space solar cells,Irradiation
更新于2025-09-19 17:13:59
-
Matrix effect impact on measuring hardness of metals bombarded by accelerated ions using laser induced breakdown spectroscopy
摘要： For safety reasons, the need of a fast in situ technique for measuring change in surface hardness of nuclear reactor vessel walls due to ion bombardment has great importance. Material hardness measurement using laser induced breakdown spectroscopy has been demonstrated as a new promising technique. The effect of the material matrix is one of the challenges that this technique for hardness measurement may face. In this work, the plasma excitation temperature Te has been used to measure the relative hardness of some pure Ti and Ti alloy samples with different hardnesses. The hardness of these samples was changed by irradiating the samples with 1 MeV carbon (C) ions with different doses. On studying the average crystallite size of these samples using x-ray diffraction and its relation with hardness, it was found that pure Ti samples and Ti alloys show different behaviors. On the other hand, it was found that although there is a good linear relation between Te and the Vickers hardness, the sample matrices have a strong influence on the measurements, especially for samples with small hardness value differences, irrespective of their average crystallite size.
关键词： titanium,matrix effect,hardness,LIBS
更新于2025-09-19 17:13:59
-
In-situ Monitoring on Micro-hardness of Laser Molten Zone on AISI4140 Steel by Spectral Analysis
摘要： The real-time monitoring technology plays a significant role in the field of laser aided manufacturing. It not only ensures the product quality, but also saves time and expenditure on the subsequent testing. To develop a method to monitor the properties of laser molten zone, in this paper, the AISI4140 steel samples were melted by laser with different parameters. At the same time, the plasma spectra were detected during real-time laser processing. The evolutions for both emission spectra and hardness of molten zone were researched in this work. To correlate the intensity of spectral line with the hardness of molten zone, the method of dimensionless analysis was used in this experiment. As the results shown, in a dimensionless system, there was a linear correlation between dimensionless micro-hardness of molten zone (H*) and dimensionless laser energy density(ln(δ*)); the dimensionless micro-hardness could be expressed by a piecewise function using dimensionless intensity of Fe I spectral lines(I*), dimensionless velocity(v*) and dimensionless laser energy density as variables; depending on the quantitative relation among all dimensionless, a monitoring system of hardness of molten zone was established; by testing under different parameters of laser processing, the mean error of prediction is lower than 3.1%. It means the emission spectroscopy can be a potential way to monitor the properties of parts prepared by laser processing.
关键词： AISI4140 steel,plasma spectra,laser aided manufacturing,micro-hardness,dimensionless analysis,real-time monitoring
更新于2025-09-19 17:13:59
-
Optimization of welding parameters in laser welding of Ti6Al4V using VIKOR optimization method
摘要： Ti6Al4V alloys are widely preferred in the biomedical industries owing to its higher corrosion resistance in human body environment. Welding plays a critical role in the manufacture of complicated biomedical components. Hence, the necessity to identify suitable joining process for joining Ti6Al4V is very important. In this work, an attempt is made to study the CO2 laser welding of titanium sheets (Ti6Al4V) having dimensions of 100 (cid:1) 60 (cid:1) 3 mm. Laser welding was done based on L9 Taguchi array with welding speed (v), laser power(P), and shielding gas ?ow rate(f) as input parameters. The weld quality was analysed by measuring the depth of penetration (DOP), bead width (BW), and hardness values. Full penetration was observed only in two welding trials. The optimized parameters were identi?ed by using the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) multi-objective optimization technique. Analytic Hierarchy Process (AHP) is used for determining the weights of the relative importance of the output factors. VIKOR method identi?ed that the 7th experimental run (power = 1.3 kW, speed = 0.3 m/min, shielding gas ?ow rate = 20 L/min) as the optimized parameter for getting the weld with full depth of penetration, lesser bead width, higher microhardness values in the fusion zone (FZ) and heat affected zone (HAZ). The metallurgical characterization of the optimized weld is also dicussed with the aid of microstructures taken from Scanning Electron Microscope (SEM).
关键词： CO2 laser welding,Hardness values,Bead geometry,VIKOR multi-objective optimization technique,Ti6Al4V
更新于2025-09-19 17:13:59
-
Radiation hardness investigation of heterojunction solar cell structures with TCO antireflection films
摘要： Phosphorus doped silicon carbide film as emitter in heterojunction structure was deposited on p-type Si(100) wafers at various deposition conditions by means of PECVD technology using silane (SiH4), methane (CH4), hydrogen (H2) and phosphine (PH3, 2 vol.% in H2) gas as precursors. ITO or IZO film was RF magnetron sputtered on top of the different P doped a-SiC:H(n) film. Irradiation of structures with Xe ions to total fluency 5x1011 cm-2 was performed at room temperature. Influence of phosphorus concentration and type of transparent conducting oxide was investigated. A deeper insight on the impact of irradiation on the electrophysical properties of sample was obtained by the analysis of complex impedance spectra.
关键词： Xe ions irradiation,RF magnetron sputtering,TCO antireflection films,radiation hardness,impedance spectra,heterojunction solar cell,PECVD
更新于2025-09-19 17:13:59
-
Prediction of Preheating Temperatures for S690QL High Strength Steel Using FEM-Simulation for High Power Laser Welding
摘要： This study investigates a method for predicting the effect of preheating temperatures on the resulting hardness for high power laser welding of high strength steel. An FEM model is introduced containing a hardness calculation based on an existing model. Moreover, the hardness values of experimental results have been measured in order to show the performance of the model. The hardness calculation requires the chemical composition and the t8/5-time at the point of measurement. It is claimed that a calibration of the melt pool width and depth at room temperature only is enough to get reasonable results from the FEM-model for higher preheating temperatures. From the experimental result of a single experiment the width of a weld seam and the depth was deducted. In this study experiments have been done at various preheating temperatures in order to show the correlation between the model and the experimental results at various temperatures. The hardness equation provides suitable results in the verification with the measurements. The prediction of preheating temperature can be done with the resulting t8/5-time of the FEM-model. This method can decrease the amount of time and costs within a production according to testing and analyzing a matrix of process parameters. Moreover it is concluded that this methodology might be used for single item production.
关键词： Deep penetration laser welding,FEM-welding simulation,High strength steel,Preheating,Predicting hardness
更新于2025-09-19 17:13:59
-
Study on laser cladding and properties of AZ63-Er alloy for automobile engine
摘要： Aiming at the problem of the poor corrosion resistance of magnesium alloys for automobiles, Al-TiC and Al-TiC-Y2O3 cladding layers were prepared on the AZ63-Er alloy by laser cladding technology, studied the effects of Al:TiC mass ratio and Y2O3 addition on the microstructure, phase composition, hardness and corrosion resistance of the cladding layer. The results show that the Al-TiC laser cladding layer with different mass ratios has metallurgical bonding with AZ63-Er alloy substrate, and there are no pores or cracks at the interface. The main phases of the Al-TiC laser cladding layer are Ti3AlC, TiC, Mg2Al3, Al3Mg2, Al, Mg, AlMg and Ti6O. The hardness of laser cladding layer with the mass ratios of Al:TiC are 8:1, 4:1 and 2:1 are about 2.75, 3.24 and 3.94 times of the substrate. The corrosion resistance of Al-TiC cladding layer is higher than that of the AZ63-Er alloy substrate, and the corrosion resistance of the Al:TiC cladding layer with the mass ratio of 8:1 is the best. Al3Y and Al4MgY phases are formed in the Al-TiC-Y2O3 cladding layer after Y2O3 addition. The hardness of the Al-TiC-Y2O3 cladding layer is significantly higher than that of the Al-TiC cladding layer. The Al-TiC-Y2O3 composite cladding layer has the best hardness and corrosion resistance when the Y2O3 content is 0.6%.
关键词： surface modification,laser cladding,hardness,AZ63-Er alloy,corrosion resistance
更新于2025-09-19 17:13:59
-
Theoretical Study of the Effect of Different π Bridges Including an Azomethine Group in Triphenylamine-Based Dye for Dye-Sensitized Solar Cells
摘要： Ten molecules were theoretically calculated and studied through density functional theory with the M06 density functional and the 6-31G(d) basis set. The molecular systems have potential applications as sensitizers for dye-sensitized solar cells. Three molecules were taken from the literature, and seven are proposals inspired in the above, including the azomethine group in the π-bridge expecting a better charge transfer. These molecular structures are composed of triphenylamine (donor part); di?erent combinations of azomethine, thiophene, and benzene derivatives (π-bridge); and cyanoacrylic acid (acceptor part). This study focused on the e?ect that the azomethine group caused on the π-bridge. Ground-state geometry optimization, the highest occupied molecular orbital, the lowest unoccupied molecular orbital, and their energy levels were obtained and analyzed. Absorption wavelengths, oscillator strengths, and electron transitions were obtained via time-dependent density functional theory using the M06-2X density functional and the 6-31G(d) basis set. The free energy of electron injection (?Ginj) was calculated and analyzed. As an important part of this study, chemical reactivity parameters are discussed, such as chemical hardness, electrodonating power, electroaccepting power, and electrophilicity index. In conclusion, the inclusion of azomethine in the π-bridge improved the charge transfer and the electronic properties of triphenylamine-based dyes.
关键词： chemical hardness,azomethine,free energy of electron injection,DSSC
更新于2025-09-16 10:30:52
-
Application of Laser Metal Deposition for a New Model of Assembled Camshaft
摘要： This work introduces the invention of an alternative camshaft manufacturing method aimed at improving the efficiency of the process and providing a more flexible product. The innovation consists in the laser metal deposition (LMD) of a profile on the shaft in order to realize a coupling stretch where the cam is fixed by interference. Alternative profile materials (1.4404 steel and Inconel 625 alloy) are deposited on a 1.0421 steel tube at different laser power levels and powder flow rate. The effect of the process parameters on the deposited profile is investigated initially through the evaluation of indirect quality attributes, such as deposit dimensions, hardness values, and microstructure. Then, the coupling force resulting from the press-fit test is evaluated. Finally, the best configuration of this new assembled camshaft is tested with a torsion test rig. Performances of the new assembled camshaft are compared with those of traditional products, leading to the validation of this innovative solution. The preliminary feasibility of the LMD application to the production of an assembled camshaft is demonstrated.
关键词： additive manufacturing,cladding,hardness,testing,laser metal deposition (LMD),dilution
更新于2025-09-16 10:30:52
-
Tailoring the Pressure Profile of TEA-CO2 Laser-Induced Shock Waves for Mechanical Forming and Separation Processes
摘要： For laser shock processes, the acting pressure can be increased by confining the propagation of the laser-induced plasma. Water or glass is commonly used as confinement for laser shock waves induced by Nd:YAG-lasers. This is not possible for the longer wavelength of TEA-CO2 lasers due to higher absorption coefficients. Instead, the acting pressure can be manipulated with a pressure cell above the workpiece. Two different pressure cells were designed to test the versatility of this concept. A cylindrical pressure cell design was used to confine the propagation of the laser-induced plasma and a parabolic pressure cell design was used to reflect the shock wave back to the workpiece. The effect of the pressure cells was analysed by time-resolved force measurements and evaluated for maximum force and force duration. This study shows that the cylindrical pressure cell strongly increases the maximum force while the parabolic pressure cell maximises the duration of force application. Furthermore, the pressure cells have been applied to the laser shock-based processes laser shock punching and LiSE hardness measurement. The cylindrical pressure cell strongly enhances the results of both processes, while the parabolic pressure cell shows only a minor effect.
关键词： Micro punching,TEA CO2 laser,Indentation hardness,Laser supported detonation wave,Micro manufacturing
更新于2025-09-16 10:30:52