A New Complex Eta-Carbide
1952; Nature Portfolio; Volume: 169; Issue: 4297 Linguagem: Inglês
10.1038/169411a0
ISSN1476-4687
AutoresA. Taylor, Klaus-Jürgen Sachs,
Tópico(s)Advanced materials and composites
ResumoTHE crystal structures of many carbides occurring in alloy steels have now been elucidated. One of their most striking characteristics is that they exist over quite extensive ranges of composition by permitting a high degree of atomic substitution to occur. A typical example is the η-carbide of high-speed steel, which extends over the range Fe4W2C to Fe3W3C. Structurally similar carbides have been shown by V. Adelsköld, A. Sunderlin and A. Westgren1to occur in the systems cobalt–tungsten–carbon, nickel–tungsten–carbon and iron–molybdenum–carbon. The stability of these η-carbides seemed to decrease in the order Fe3W3C, Co3W3C and Ni3W3C, and it was concluded that the reason for the non-occurrence of this type of carbide in the systems cobalt – molybdenum – carbon and nickel – molybdenum–carbon was due to their low stability, which caused them to decompose in cooling from the melt. In the chromium–tungsten–carbon alloys a quite different cubic carbide phase was found having the. same structure as the cubic carbide Cr23C6.
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