Texture and mechanical properties of EUROFER 97 steel processed by ECAP

Abstract

Abstract:The EUROFER 97 steel was processed by equal channel angular pressing (ECAP) at 550 • C for four passes via route C. The starting material consisted of ferrite-martensite dual phase composed by small subgrains of about 0.5 m and low angle boundaries less than 5 • . The volume fraction of second phase particles was around 10 vol.%, besides a texture formed by several fibers orientations belonging to the zone axes 110 , 111 and 112 . Increasing ECAP deformation, this microstructure became into equiaxed grain structures of less than 1 m, and the misorientation between contiguous grains increased. This refine-ment of the microstructure was accompanied by the development of a new texture described by a family of fiber orientations related by rotations around axes 110 and 111 . Tensile tests have revealed that an ECAP treatment at 550 • C for two passes could significantly strengthen the tempered material still maintaining good ductility.

Grain boundary misorientation and positron annihilation characteristics in steel Eurofer processed by equal channel angular pressing

“…3c and d show. Also, the corresponding pole figures reveal that the texture evolves into a stable orientation, which is congruent with the macrotexture measurements elsewhere reported for ECAP-processed Eurofer [21].…”

“…The characteristic texture of multi-fiber orientations in as-tempered material could induce different deformation modes, thus different regions of the material should respond with different strain rates implying an inhomogeneous stress state. In contrast, this effect would be less pronounced in the ECAP-deformed material where the texture is described by a single h110i fiber [21]. So high-stress exponent values cannot be explained by the classical deformation mechanisms such as dislocation climb, slip, or grain boundary sliding that yield stress exponent values of 5, 3, or 2, respectively [32].…”

“…Therefore, the microstructural characterization of the Eurofer steel in the as-processed conditions and deformed at working temperatures is crucial to understand and predict its failure under service conditions. The effects of ECAP deformation at 550°C on the grain size, mean grain boundary misorientation, crystallographic macrotexture, and mechanical properties of the Eurofer steel have been elsewhere reported [21]. In order to correlate the ECAP processing of this steel with the changes induced in the grain structure characteristics and their effect on the high-temperature mechanical behavior, misorientation measurements between contiguous grains, strain rate jump experiments, and tensile tests, along with positron lifetime measurements, have been performed on samples in the as-tempered condition and after ECAP processing.…”

A roadmap for tailoring the strength and ductility of ferritic/martensitic T91 steel via thermo-mechanical treatment

“…By ECAE at high temperature, carbides in T91 steel, which were previously located at prior austenitic grain boundaries (PAGBs), were refined and redistributed throughout the matrix [14]. The tempered EUROFER 97 steel can be strengthened without significant loss of ductility by hot-ECAE [26].…”

Mechanical Spectroscopy Of Equal-Channel Angular Pressed Fe-Cr Alloys And Tungsten

“…The equal-channel angular pressing (ECAP) is an important technique, which can produce a fine grain size in bulk materials in the ultrafine scale and the nanometer scale [3]. The ECAP technique is successfully used to produce a variety of materials such as Cu [4], Mg [5], Fe [6], W [7], 7075 Al alloy [8], low carbon steel [9], Eurofer 97 steel [10], Al-Mg [11], etc.…”