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51.
Herbert Danninger Tayfun Kara Michael Ruhnow Hans -Jürgen Ullrich 《Mikrochimica acta》1990,101(1-6):219-229
Homogenization of Mo, W and Cr in alloyed P/M carbon steels during sintering with a transient liquid phase has been investigated by microscopic and microanalytical means. The reaction was found to start with carburization of the VIa metal, continues with the formation of different carbides, and generation of a liquid phase between the carbide and -Fe. The steady state equilibrium remains stable until all VIa metal has been consumed. Microprobe analysis was found to yield optimum results if selected model samples, in which homogenization should not proceed too fast, are investigated.Dedicated to Professor Günther Tölg on the occasion of his 60th birthday 相似文献
52.
H. Bach 《辐射效应与固体损伤》2013,168(3):213-214
Abstract The kinetics of short-range atomic ordering in austenitic Fe-17 Cr-xNi (x=10-25 wt%) alloys and in Sc-doped alloys has been studied by residual resistivity measurements during isochronal annealing in the temperature range 300-815 K. Dynamics of residual resistivity variations has shown that (i) diffusion in these alloys is observable at temperature above 700 K, (ii) preliminary cold-work deformation as well as doping by Sc atoms forms the disorder atomic structure in the austenitic matrix. It was found that Sc Atoms retard the atomic ordering process and shift it to higher temperatures. The value of temperature shift is increased from 25 to 80 K when the nickel concentration grows up to 25 wt%. 相似文献
53.
The defect structures in Ni, Fe–15Cr–16Ni and Ti-added modified SUS316SS (modified SUS316) were examined after neutron irradiation below 0.3 dpa by the Japan Materials Testing Reactor and Belgian Reactor 2 to compare their defect structural evolution. The growth behaviour of interstitial-type dislocation loops (I-loops), stacking fault tetrahedra (SFTs) and voids was found to be quite different among these specimens. I-loops developed at lower temperatures in Ni than in Fe–15Cr–16Ni and modified SUS316, and more swelling occurred in Ni than in Fe–15Cr–16Ni. Finally, there were no voids in modified SUS316. These results were analysed in terms of the I-loop energy. A large discrepancy was found between the analytical results and experimental observations for Ni and modified SUS316, which suggests the formation of unfaulted I-loops directly from collision cascades. The growth of SFTs was detected in Fe–15Cr–16Ni and modified SUS316, and can be explained by a change in the dislocation bias of SFTs resulting from the absorption of alloying elements. 相似文献
54.
Marina Tikhonova Yuliya Kuzminova Xiaoying Fang Weiguo Wang Rustam Kaibyshev 《哲学杂志》2013,93(36):4181-4196
The effect of processing and annealing temperatures on the grain boundary characters in the ultrafine-grained structure of a 304-type austenitic stainless steel was studied. An S304H steel was subjected to multidirectional forging (MDF) at 500–800°C to total strains of ~4, followed by annealing at 800–1,000°C for 30 min. The MDF resulted in the formation of ultrafine-grained microstructures with mean grain sizes of 0.28–0.85 μm depending on the processing temperature. The annealing behaviour of the ultrafine-grained steel was characterized by the development of continuous post-dynamic recrystallization including a rapid recovery followed by a gradual grain growth. The post-dynamically recrystallized grain size depended on both the deformation temperature and the annealing temperature. The recrystallization kinetics was reduced with an increase in the temperature of the preceding deformation. The grain growth during post-dynamic recrystallization was accompanied by an increase in the fraction of Σ3n CSL boundaries, which was defined by a relative change in the grain size, i.e. a ratio of the annealed grain size to that evolved by preceding warm working (D/D0). The fraction of Σ3n CSL boundaries sharply rose to approximately 0.5 in the range of D/D0 from 1 to 5, which can be considered as early stage of continuous post-dynamic recrystallization. Then, the rate of increase in the fraction of Σ3n CSL boundaries slowed down significantly in the range of D/D0 > 5. A fivefold increase in the grain size by annealing is a necessary condition to obtain approximately 50% Σ3n CSL boundaries in the recrystallized microstructure. 相似文献
55.
Tongyan Pan 《光谱学快报》2013,46(4):268-276
This work investigates the potential use of an intrinsically conducting polymer—polyaniline—that, when mixed in polyvinyl-butyral and top-coated with an acrylic resin layer, demonstrates comparable performance to the existing coating systems, according to the experimental data from two ASTM standard tests performed to evaluate its overall corrosion durability and tensile adhesion (pull-off strength). Formulation of the polyaniline-based wash primer was provided. Scanning Kelvin probe force microscopy (SKPFM) was used to analyze the microscopic mechanisms of the superior performance. The polyaniline-based primer demonstrated potential surface ennobling and oxygen smearing-out capabilities in this study. Under the protection of a top coat, the primer provided both preventive and corrective protection in a smart mode. The layered structure including an ICP primer, as demonstrated in this study, constitutes a viable smart coating system for corrosion protection of metallic materials. 相似文献
56.
Chengyun Cui 《Applied Surface Science》2008,254(20):6537-6542
The effects of laser surface irradiation on microstructure of AISI 304 stainless steel were investigated. The stainless steel surface was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD patterns indicated that different oxides, such as chromium oxides and manganese oxides were fabricated successfully on the surface of the stainless steel by Nd:YAG pulsed laser irradiation. The effects of the growth conditions such as the laser power density on the morphologies of the different oxides have been investigated. From the FESEM, EDS (energy-dispersive spectrum) and TEM observations, the oxides with triangle-like, quadrangular and hexagonal morphologies have been fabricated successfully. The XPS was used to verify the formed oxides which had been detected by the XRD patterns. It was considered that laser power density had a critical role in the formation of different oxides. 相似文献
57.
通过对 11 组 19 个角钢插入式基础试件的抗拔试验,得到了角钢在不同埋置长度、不同锚固形式下的抗拔承载力、角钢与混凝土间的粘结应力分布、平均粘结应力以及角钢插入式基础的破坏形式、最大试验荷载等。为工程设计提供了基础数据。 相似文献
58.
A novel solid-phase microextraction fiber based on a stainless steel wire coated with Au nanoparticles was prepared and has been applied, coupled with gas chromatography, to the extraction of aromatic hydrophobic organic chemical pollutants in rainwater and soil extract. The solid-phase microextraction fiber exhibited excellent extraction efficiency and selectivity. Effects of extraction time, extraction temperature, ionic strength, stirring rate and desorption conditions were investigated and optimized. Single fiber repeatability and fiber-to-fiber reproducibility were less than 7.90% and 26.40%, respectively. The calibration curves were linear in a wide range for all analytes. Correlation coefficients ranged from 0.9941 to 0.9993. The as-established SPME-GC method was used successfully to two real natural samples. Recovery of analytes spiked at 10 μg L(-1) and 100 μg L(-1) ranged from 78.4% to 119.9% and the relative standard deviations were less than 11.3%. 相似文献
59.
Surface characterisation and electrochemical behaviour of porous titanium dioxide coated 316L stainless steel for orthopaedic applications 总被引:1,自引:0,他引:1
S. Nagarajan 《Applied Surface Science》2009,255(7):3927-3932
Porous titanium dioxide was coated on surgical grade 316L stainless steel (SS) and its role on the corrosion protection and enhanced biocompatibility of the materials was studied. X-ray diffraction analysis (XRD), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were carried out to characterise the surface morphology and also to understand the structure of the as synthesised coating on the substrates. The corrosion behaviour of titanium dioxide coated samples in simulated body fluid was evaluated using polarisation and impedance spectroscopy studies. The results reveal that the titanium dioxide coated 316L SS exhibit a higher corrosion resistance than the uncoated 316L SS. The titanium dioxide coated surface is porous, uniform and also it acts as a barrier layer to metallic substrate and the porous titanium dioxide coating induces the formation of hydroxyapatite layer on the metal surface. 相似文献
60.