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Malgorzata Łazarska Tadeusz Z. Wozniak Zbigniew Ranachowski Andrzej Trafarski Grzegorz Domek 《Metals and Materials International》2017,23(3):426-433
Bearing steel 100CrMnSi6-4 and tool steel C105U were used to carry out this research with the steels being austempered to obtain a martensitic-bainitic structure. During the process quite a large number of acoustic emissions (AE) were observed. These signals were then analysed using neural networks resulting in the identification of three groups of events of: high, medium and low energy and in addition their spectral characteristics were plotted. The results were presented in the form of diagrams of AE incidence as a function of time. It was demonstrated that complex transformations of austenite into martensite and bainite occurred when austempering bearing steel at 160 °C and tool steel at 130 °C respectively. The selected temperatures of isothermal quenching of the tested steels were within the area near to MS temperature, which affected the complex course of phase transition. The high activity of AE is a typical occurrence for martensitic transformation and this is the transformation mechanism that induces the generation of AE signals of higher energy in the first stage of transition. In the second stage of transformation, the initially nucleated martensite accelerates the occurrence of the next bainitic transformation. 相似文献
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Palacz Michal Melka Bartlomiej Wecki Bartosz Siwiec Grzegorz Przylucki Roman Bulinski Piotr Golak Slawomir Blacha Leszek Smolka Jacek 《Metals and Materials International》2020,26(5):695-707
Metals and Materials International - One of the promising technology that guarantee the high-purity of the processed metal is induction skull melting. The quality of the melting process within such... 相似文献
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Wojciech Dro?d? Micha? Ko?odziejski Grzegorz Markiewicz Anna Jenczak Artur R. Stefankiewicz 《International journal of molecular sciences》2015,16(7):16300-16312
We describe here the generation of new donor-acceptor disulfide architectures obtained in aqueous solution at physiological pH. The application of a dynamic combinatorial chemistry approach allowed us to generate a large number of new disulfide macrocyclic architectures together with a new type of [2]catenanes consisting of four distinct components. Up to fifteen types of structurally-distinct dynamic architectures have been generated through one-pot disulfide exchange reactions between four thiol-functionalized aqueous components. The distribution of disulfide products formed was found to be strongly dependent on the structural features of the thiol components employed. This work not only constitutes a success in the synthesis of topologically- and morphologically-complex targets, but it may also open new horizons for the use of this methodology in the construction of molecular machines. 相似文献
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