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.

High strain rate superplasticity in friction stir processed Al–Mg–Zr alloy

Abstract: Al–4Mg–1Zr extruded bar was subjected to friction stir processing (FSP), resulting in generation of a fine microstructure of 1.5 μm grain size. Superplastic deformation behavior of FSP Al–4Mg–1Zr alloy was investigated in strain rate range of 1×10−3 to 1 s−1 and temperature range of 350–550 °C and compared with that of as-rolled one. It is indicated that the FSP alloy exhibited significantly enhanced superplasticity at a high strain rate of 1×10−1 s−1, and a maximum elongation of 1280% was obtained at 525 °C and 1×10−1 s−1. Further, the FSP Al–4Mg–1Zr alloy exhibited excellent thermal stability at high temperature, and a large elongation of 1210% was observed at 550 °C and 1×10−1 s−1. Moreover, FSP resulted in a significant decrease in the flow stress in Al–4Mg–1Zr alloy. At a strain rate of 1×10−2 s−1, the flow stress (∼7 MPa) of FSP Al–4Mg–1Zr at 450 °C was comparable to that of as-rolled alloy at 550 °C.

Effect of friction stir processing tool probe on fabrication of SiC particle reinforced composite on aluminium surface

Abstract: An investigation has been carried out of the effects of tool probe shape and size on the formation of surface composite by uniformly distributing SiC particles into a surface layer of an A1050-H24 aluminium plate through friction stir processing (FSP). Tool probes of three different diameters (3, 5 and 7 mm) and four different shapes (circular with threads, circular without threads, square and triangular) have been used to fabricate the surface layers at rotation speeds of 1500–2250 rev min−1 and a travelling speed of 1·66 mm s−1. The SiC particles were packed into a groove of 3 mm width and 1·5 mm depth cut on the aluminium plate and covered by an aluminium sheet of 2 mm thickness. A rotating tool was plunged into the plate through the cover sheet so that the tip of the probe reached beyond the bottom of the groove. As a result, it was found that the square probe dispersed the SiC particles homogeneously in the nugget zone compared with other probe shapes regardless of the rotation speeds. Furthe...

Simulation and experimental investigation of FSP of AZ91 magnesium alloy

Abstract: A thermo-mechanical simulation of the friction stir processing (FSP), using the DEFORM 3D software based on Lagrangian implicit, was developed and verified by the experimental results. Simulation can successfully predict the temperature and effective strain distributions. Material flow around the tool pin was examined using the point tracking. It was found that the major part of material flow occurs at the advancing side, and consequently, stirred zone (SZ) stretches toward the advancing side. However, material at the retreating side moves slightly in backward direction. The material deformation and the peak temperature influence on the microstructural characters and can determine the width of SZ. Based on the simulation, effective strain and temperature histories of material around the tool pin were also calculated. The amount of effective strain and peak temperature required for recrystallization at the advancing and retreating sides as well as at the bottom of SZ was determined. Therefore, the width of SZ can be predicted by the simulation.

Grain refinement of aluminum alloys by friction stir processing

Abstract: Combining friction stir processing (FSP) with rapid cooling, samples with grain sizes of ∼100, 180, 300 and 500 nm have been produced in commercial 7075 Al by controlling the cooling rate. Microstructure characteristics of the processed materials were investigated. The nanocrystalline structures formed in the sample processed with the highest cooling rate consist of high-angle grain boundaries, and are free of dislocation cell structures. High temperature discontinuous dynamic recrystallization is the mechanism responsible for the nanocrystalline creation. Dislocations and recovery structures were observed in the large grains of samples with slower cooling rates. The developed grains are a result of the evolution of the initial nanocrystals formed around pin tool during the FSP.