Topic
Friction stir processing
About: Friction stir processing is a research topic. Over the lifetime, 2977 publications have been published within this topic receiving 62158 citations.
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TL;DR: In this paper, an equiatomic CoCrFeNiCu HEA with excellent mechanical properties obtained via friction stir processing (FSP) was presented, which largely improved the hardness and yield strength of the HEAs with a value of 380 HV and more than 1150 MPa.
Abstract: High-entropy alloys (HEAs) are a new class of materials with a potential engineering application, but how to obtain ultrafine or nano-sized crystal structures of HEAs has been a challenge. Here, we first presented an equiatomic CoCrFeNiCu HEA with excellent mechanical properties obtained via friction stir processing (FSP). After FSP, the Cu element segregation in the cast CoCrFeNiCu HEA was almost eliminated, and the cast coarse two-phase structure (several micrometers) was changed into an ultrafine-grained single-phase structure (150 nm) with a large fraction of high-angle grain boundaries and nanoscale deformation twins. This unique microstructure was mainly attributed to the severe plastic deformation during FSP, and the sluggish diffusion effect in dynamics and the lattice distortion effect in crystallography for HEAs. Furthermore, FSP largely improved the hardness and yield strength of the CoCrFeNiCu HEA with a value of 380 HV and more than 1150 MPa, respectively, which were > 1.5 times higher than those of the base material. The great strengthening after FSP was mainly attributed to the significant grain refinement with large lattice distortion and nano-twins. This study provides a new method to largely refine the microstructure and improve the strength of cast CoCrFeNiCu HEAs.
28 citations
Patent•
20 Feb 2009TL;DR: In this article, a tool having a columnar tip-side part, a rotating unit for rotating the tool on a central axis, a first pressing unit for pressing a tip of the tool rotated by the rotating unit against a work, and a jig having a tool insertion hole into which the tool was inserted so that the tip side part was encircled around the jig.
Abstract: An apparatus for a friction stir and a friction stir processing of the present invention suppress an occurrence of a surface defect in an area processed by the friction stir. The apparatus for the friction stir includes a tool having a columnar tip-side part, a rotating unit for rotating the tool on a central axis, a first pressing unit for pressing a tip of the tool rotated by the rotating unit against a work, a jig having a tool insertion hole into which the tip-side part of the tool is inserted so that the tip-side part of the tool is encircled around the jig, a second pressing unit for slidably pressing the jig against the work, and a press control unit for controlling the first pressing unit so that the tip-side part of the tool is gradually pulled out of the work by the first pressing unit while moving the tool and the jig relative to the work, in a state that the tool is rotated by the rotating unit and the tip of the tool has been sunk into the work to a predetermined depth by the first pressing unit.
28 citations
TL;DR: In this paper, the kinetics of the Al-Ti reaction during isothermal annealing and friction stir processing (FSP) were studied, and the reaction rate constant k during FSP was substantially enhanced compared with that during annaling.
28 citations
TL;DR: In this paper, the solid-state friction stir processing (FSP) was introduced to surface nitriding on a Ti-6Al-4V substrate under nitrogen atmosphere, and a sound and thick surface nitride layer was successfully prepared and detailed by XRD, SEM and EDS methods.
28 citations
TL;DR: In this paper, the microstructure and mechanical properties of enhanced tool steel surfaces produced using a friction stir welding (FSW) related procedure, called friction stir processing (FSP), are analyzed.
28 citations