H. K. D. H. Bhadeshia

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There are difficult problems in materials science where the general concepts might be understood but which are not as yet amenable to scientific treatment. We are at the same time told that good engineering has the responsibility to reach objectives in a cost and time–effective way. Any model which deals with only a small part of the required technology is(More)
Friction stir welding is a refreshing approach to the joining of metals. Although originally intended for aluminium alloys, reach of FSW has now extended to a variety of materials including steels and polymers. This review deals with the fundamental understanding of the process and its metallur-gical consequences. The focus is on heat generation, heat(More)
Methods for the dilatometric determination of the martensite start temperature of steels are discussed, with emphasis on noise in the experimental data. The methods are tested on a new set of experiments using a specially prepared steel. Relying on the first detection of expansion due to transformation is fraught with difficulties. Instead, an offset method(More)
Steels can be designed to exploit the coordinated motion of atoms during the bainite and martensite reactions. In this way it has been possible to make exceptionally strong and tough alloys in bulk form, and at an affordable price. Crystal sizes can be reduced to between 20–180 nm, by annealing heterogeneously deformed martensite, or by forming bainite(More)
Recent changes in the design of steam turbine power plant have necessitated the replacement of bolted ¯anges with welded joints. The design process therefore requires a knowledge of the creep rupture strength of the weld metal consumed in the welding process. This paper presents a method which can be used to estimate the creep rupture strength of ferritic(More)