Abstract
Tube high-pressure shearing (t-HPS) processing was performed on a eutectic Bi–Sn (57/43) alloy for 0.25, 1, 5 and 20 turns. The selected samples were stored at room temperature for up to 56 days to examine the strain weakening and self-annealing behavior of the alloy. The results showed that t-HPS processing gradually refined the microstructure and led to decreasing of microhardness, but microhardness increased slowly during the subsequent storage at room temperature. Shear localization of the eutectic structure during t-HPS processing was observed as large amounts of narrow dense lamellar zones were visible in the deformed microstructures. The Bi–Sn (57/43) alloy processed by t-HPS exhibited significantly enhanced superplastic properties with elongations up to >1800% in a sample after t-HPS processing for 20 turns. This high elongation is attributed to the breaking of the lamellar structure and the very small grain size.
Highlights
Considerable interest has developed over the last two decades to producing and measuring the mechanical properties of materials with exceptionally small grain sizes.Ultrafine-grained (UFG) metals are defined as metals where the average grain size is less than ~1 μm [1] and these small grains divide into the two categories of submicrometer grains with sizes of 100–1000 nm and nanometer grains where the average size is
As discussed in a comprehensive review [3], the two main techniques of severe plastic deformation (SPD) processing are equal channel angular pressing (ECAP), where a rod or a bar is pressed through a die constrained within a channel bent through a sharp angle [4], and high-pressure torsion (HPT), where the sample is generally in the form of a thin disk subjected to high pressure and concurrent torsional straining [5]
Both ECAP and HPT are effective for processing to produce metals with very small grains, but the procedures are different because ECAP is a discontinuous and laborintensive process in which the sample is removed and reinserted into the die between each pass whereas HPT is a continuous process where the sample is torsionally strained up to the required maximum numbers of rotations
Summary
Considerable interest has developed over the last two decades to producing and measuring the mechanical properties of materials with exceptionally small grain sizes.Ultrafine-grained (UFG) metals are defined as metals where the average grain size is less than ~1 μm [1] and these small grains divide into the two categories of submicrometer grains with sizes of 100–1000 nm and nanometer grains where the average size is
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
