17
July 2003
Stainless steel: Creep mission
Under constant low-stress loading, and over extended time periods, many materials undergo creep, a permanent deformation that is particularly marked at elevated temperatures. Incorporation of fine particles into metals and alloys, also called dispersion strengthening, is used to impart creep-resistance at high temperatures. A team from Japan's National Institute for Materials Science, Tsukuba, has developed a dispersion strengthening technique that incorporates nanometre-scale carbonitride particles into a martensitic stainless steel (a chromium-containing steel hardened by heat treatment) for improved creep performance. The creep strength of this 'nano-treated' steel is greatly increased due to a novel grain boundary pinning mechanism, achieving an increase of two orders of magnitude in time-to-rupture at 650 °C, compared with the best of the current crop of creep-resistant steels. And production of large-scale creep-resistant components should be more economical using the methods described here.
Creep-strengthening of steel at high temperatures using
nano-sized carbonitride dispersions
MASAKI TANEIKE,
FUJIO ABE & KOTA SAWADA
Nature 424, 294–296 (2003);
doi:10.1038/nature01740
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