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.

Effect of Processing Parameters on the Mechanical Properties of Interstitial Free Steel Subjected to Friction Stir Processing

Abstract: In the present work, the effect of friction stir processing parameters on the mechanical properties of an interstitial free steel was studied. Four rotating speeds (800, 1250, 1600, 2000 rpm) and two traverse speeds (31.5 and 63 mm/min) were employed. On both sides of specimens, a nanograin layer with the thickness and nanograins of 150 μm and 50-100 nm were formed, respectively. For the specimen processed at rotating speed of 1600 rpm and the traverse speed of 31.5 mm/min, the maximum strength was achieved, which was about 80% increase in the strength comparing to that of base material. For constant traverse speed, the increase in the rotation speed from 800 to 1600 rpm led to a decrease in uniform and total elongation of friction stir processed samples. By contrast, when the rotating speed exceeded 1600 rpm, the uniform and total elongation was increased again, while there was a drop in strength. The results of microhardness indicate more than threefold increase in the hardness of the stirred zone comparing to that of base material.

Dynamic dissolution and transformation of LPSO phase during thermomechanical processing of a GWZ magnesium alloy

Abstract: An extruded Mg-8.2Gd-3.6Y–1.6Zn–0.5Zr alloy containing blocky long-period stacking-ordered (LPSO) phase was subjected to a set of single and multi-pass friction stir processing trials. The evolutions of the microstructure and the secondary phases were investigated in details, and the correlations between the microstructure, the macro-texture and the room-temperature mechanical properties were explained. An outstanding grain refinement was achieved after applying just one friction stir processing pass, while the coarse blocky long-period stacking ordered phase was significantly broken into the fine particles. The occurrence of particle-stimulated nucleation process was identified as the main recrystallization mechanism, and this in turn could lead to appreciable texture weakening. In addition, some of the secondary phases were dissolved in the matrix and successively transformed into cubic RE-rich particles dynamically. The capability of phase transformation and dynamic precipitation were intensified through higher passes and the volume fraction of dispersed RE-rich particles located at the grain boundaries was increased. An ultrafine and relatively homogenous microstructure was also developed at the highest level of imposed equivalent strain. In the current work, the room-temperature mechanical properties of the thermomechanically processed materials were also explored. In spite of previous reports on the severely deformed magnesium alloys, the strength and ductility were significantly improved after friction stir processing. These were explained considering the grain refinement, fragmentation, transformation, suitable distribution of the second phases, and texture weakening which was resulted from the activation of non-basal slip systems.

Investigation of friction stir processing effect on AA 2014-T6

Abstract: This study is concerned with the effects of process parameters such as speed, feed, tilt angle, and tool profile on mechanical and microstructural properties of stir processed, solution tre...

Effect of Grain Refinement on Corrosion Rate, Mechanical and Machining Behavior of Friction Stir Processed ZE41 Mg Alloy

Abstract: The aim of the present work is to modify the microstructure of ZE41 Mg alloy by friction stir processing (FSP) and to study the influence of microstructure on the corrosion, mechanical and machining behavior. Microstructural observations revealed the prevalence of grain refinement from ≈ 100 to 3.5 µm. The compound present at the grain boundary was observed to have decreased to a great extent after FSP suggesting the formation of supersaturated grains. Hardness measurements indicated increased hardness after FSP which was attributed to grain refinement effect. Tensile tests showed increased yield strength after FSP without altering the percentage of elongation which was due to the grain boundary strengthening. Corrosion performance of FSPed ZE41 was found to be similar compared with ZE41 due to the synergy of grain refinement, decreased amount of secondary phase and development of supersaturated grains. Grain size was observed as significant factor on machining characteristics as observed from improved machinability for FSPed ZE41 during drilling experiments. It was learnt from the current work that the grain-refined supersaturated ZE41 Mg alloy could be produced through FSP with better mechanical and machining behavior without deteriorating the corrosion performance.