Friction stir processing（FSP） technology was used for single pass processing of 5086 aluminum alloy. The microstructure

mechanical properties

storage modulus and damping behavior of the alloy were investigated. The results reveal that the grain in 5086 aluminum alloy is refined after FSP

and the number of second phase particles and dislocation density are decreased obviously. After FSP

the elongation of 5086 aluminum alloy is significantly enhanced

and the elongation of low rotation speed FSP sample reaches 22%

which is 83% higher than that of base metal. At 350 ℃

the internal friction value of low rotation speed FSP is 0.068

which is 55% higher than that of base material. When the strain is higher than 0.06%

small grain boundaries occur to slip and induce grain boundary damping

which takes the damping properties of FSP samples superior to that of base metal. The storage modulus of 5086 aluminum alloy is increased with the increase of temperature and strain

respectively

and the storage modulus of FSP samples is significantly higher than that of base metal.