The effects of heat treatment（solution and aging） on the microstructure and mechanical properties of 6063 aluminum alloy were investigated

and the roles of heat treatment process parameters were analyzed. The results show that with the increase of solution time from 15 min to 120 min

the grain size in the 6063 aluminum alloy is coarsened continuously

and the primary phase of Mg

2

Si in grain boundary and crystal disappears gradually and is dissolved into the matrix

while the effect of solution holding time on α-Al

8

Fe

2

Si and β-Al

5

FeSi phases can be ignored. Meanwhile

the strength and hardness of the alloy are increased firstly and then decreased

while the elongation is decreased firstly and then increased. When the aging temperature is increased from 160 ℃ to 180 ℃

the second phase in 6063 aluminum alloy is increased gradually

while the second phase in 6063 aluminum alloy is coarsened at 200 ℃

so the strength and hardness of 6063 aluminum alloy are increased firstly and then decreased with the increase of aging temperature

and the elongation is decreased firstly and then increased. When the aging holding time is 3 h or less

the amount of secondary phase is declined in 6063 aluminum alloy

while with the aging holding time of 5 hours or more

the number of dispersed second phase will be gradually increased

and obvious coarsening and growth of the second phase will occur when the aging holding time is 12 h or more. The suitable heat treatment process of 6063 aluminum alloy is 535 ℃×60 min+180 ℃×7 h

where the 6063 aluminum alloy has the maximum strength

hardness and higher elongation.