Microstructure evolution and mechanical properties of friction stir processed TiC/7085Al nanocomposites

Abstract

In this paper, homogeneously dispersed TiC nanoparticles and fine-grained composite was successfully achieved by friction stir processing (FSP) of in situ 0.5 wt.% TiC/7085Al nanocomposites with different rotational speed. The effects of the rotational speed on the microstructures and tensile properties were investigated. Experimental results showed that the stir zone (SZ) exhibited equiaxed recrystallized grains with fine size and a high fraction of high-angle grain boundaries (HAGBs) caused by dynamic recrystallization (DRX). Moreover, the tensile strength and elongation of the friction stir processed (FSPed) composite were significantly improved compared with the base composite. With the rotational speed of 1000 rpm, the composite has the smallest grain size and the optimum mechanical properties. The average grain size decreased to 1.61 μm, the yield strength (YS), ultimate tensile strength (UTS) and elongation reached to 345 MPa, 429 MPa and 17.8%, respectively.

Effect of friction stir processing on microstructures and mechanical properties of TIG cladding layer on AA7075

“…Friction stir processing (FSP) is developed from the basic principles of FSW, as one of the severe plastic deformation technologies, it forms fine-grained microstructure at a relative low processing temperature by the ultrahigh strain and strain rate [4][5][6]. FSP has been considered as a potential solid-state processing technique for not only microstructure modification but also superplasticity and in situ synthesis of composites or intermetallics [7][8][9]. In the last two decades, researches have extensively studied the effect of FSP parameters on microstructures and properties of the stir zone, and it is proved that the microstructural evolution during FSP depends on the pin profile, rotational speed and travelling speed [10][11][12][13].…”