ISSN:0947-5117    

DOI:10.1002/maco.19890400418

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19890400419

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19890400420

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19890400421

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19890400422

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19890400424

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19890400426

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIn studying the degradation experienced by alloys during their exposure to aggressive high temperature gaseous environments, thermodynamic considerations can give a good insight into which corrosion products may form as a result of the various gas/metal reactions. Although these considerations cannot be used as a predictive tool to forecast with certainty which products will actually form, they are nevertheless useful to the corrosion scientist.In the case of relatively simple environments, binary phase‐stability diagrams have been constructed and used for many years. In more complex situations, however, where the corrosive atmosphere contains several reactants, e.g. sulphur, oxygen, carbon, etc., the construction of three‐dimensional diagrams or models has been found necessary. The building of models is both time‐consuming and expensive whilst 3‐D diagrams suffer from a number of draw‐backs, not least of which is the difficulty experienced in fully comprehending the complex situations depicted by such diagrams.The purpose of this paper is to illustrate how an interdisciplinary approach, involving both the research scientist and the design engineer, has been successfully applied to this topic. A “Medusa” computer aided design (CAD) system has been used initially to construct the simpler binary phase stability diagrams direct from thermodynamic data much more quickly and efficiently than could be achieved by hand‐drawing. Of much greater significance, however, has been the evolution from these 2‐D line drawings to 3‐D perspective diagrams and finally to the superimposition of rotated images thereby enabling stereographic projections to be made. These latter projections markedly improve the user's visualisation of spatial relationships which was previously extremely diff

ISSN:0947-5117    

DOI:10.1002/maco.19890400402

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractAn investigation has been undertaken into the oxidation behaviour of manganese‐containing Fe‐28% Cr alloys in oxygen at 800° and 1000°C. The presence of the tertiary element has a detrimental effect on the oxidation resistance, resulting in enhanced scale‐growth rates during isothermal exposure and increased incidences of scale failure at temperature. This is largely due to relatively rapid rates of diffusion of manganese across the Cr2O3scale and formation of MnCr2O4spinel on its outer surface. The scale on Fe‐28% Cr‐1% Mn consists of a layer of Cr2O3, containing a small concentration of manganese, with an outer layer of the spinel oxide. During the early stages, an inner layer of the spinel also develops, but, eventually, this almost completely disappears as the manganese diffuses into the outer scale. A similar scale forms on Fe‐26% Cr‐5% Mn, but the higher manganese concentration enables a significant amount of this element to be retained in the inner regions. The overall growth rate of the scale is significantly faster than on Fe‐28% Cr or the 1% Mn

ISSN:0947-5117    

DOI:10.1002/maco.19890400403

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe interaction between oxidation and creep rupture was studied in a 17 Mn‐10 Cr austenitic steel, of interest as structural material for the internal components of fusion reactors. The observation of the creep specimens tested in air at temperatures ranging from 773 to 973 K revealed the presence of an adherent oxide scale and of a ferritic phase underneath, which forms as a consequence of the Mn depletion of the austenitic matrix.The microstructure of the two layers was investigated by optical microscopy, SEM, X‐ray diffraction, EDS and magnetic permeability measurements. The scale has a complex structure, being composed mainly of manganese oxide. The ferritic layer is completely recrystallized and does not present grain boundary precipitates as the austenitic phase does.The effect of the surface modification on the creep rupture process is discussed in the light of a recent model of deformation‐oxidation intera

ISSN:0947-5117    

DOI:10.1002/maco.19890400404

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY