Effects of friction stir processing on the thermal conductivity of a strain-hardened Al-Mg alloy

Abstract

Strain-hardened aluminum-magnesium alloy (aluminum 5052-H112 alloy) plates are successfully friction stir processed. The thermal conductivity of the FSPed aluminum alloy is consistently measured to be higher than that of the base metal, even though the amount of grain boundaries significantly increases in the FSPed zone due to grain size refinement by FSP as observed by electron back-scatter diffraction (EBSD) analysis. In terms of thermal conductivity of the selected strain-hardened aluminum alloy, the result suggests that the effect of reduced dislocation by recrystallization, which is confirmed by X-ray diffraction analysis, surpasses the effect of increased grain boundaries due to grain size refinement. As the tool rotation speed increases, the thermal conductivity of the FSPed aluminum alloy increases even more, since the dislocation density in FSPed zone decreases further while the effect of grain size refinement is diminished by a slight grain growth.

Effect of Cooling Conditions on Mechanical and Microstructural Behaviours of Friction Stir Processed AZ31B Mg Alloy

“…Following FSP with various combination, the tensile strengths slightly decrease while the elongations increases significantly. Hung et al [22] report the tensile strength of the received material AZ31-O sample as more than that of the FSP sample, while good ductility was attained with FSP.…”

“…The grain structure after tensile failure remains equiaxed, but the grain size is quite different compared with the initial grain structure. Hung et al [22] concluded that AZ31-O specimen tensile strength was higher than FSP specimens, where the better ductility was achieved with FSP. Figure 7 shows the top surface and cross-section appearance of FSP in air, SFSP and CFSP AZ31B magnesium alloys.…”

Influence of Friction Stir Process on the Physical, Microstructural, Corrosive, and Electrical Properties of an Al–Mg Alloy Modified with Ti–B Additives

“…They do not explore the affinity of grain refinement's influence on conductivity [30,31]. Due to reduced dislocation density in the FSPed zone and minor grain development, the thermal conductivity of the FSPed aluminum 5052 alloy rises [32]. In addition, FSP increases the electrical conductivity.…”