2324 aluminum alloy has excellent comprehensive performance

especially high damage tolerance performance As a structural material

it has been widely used in advanced large aircraft

and its heat treatment process is the key to ensure high comprehensive performance.This paper takes 2324 aluminum alloy for industrial use as the research object. The equilibrium phase composition

metastable phase

TTT/CCT curve and isothermal aging phase composition of 2324 aluminum alloy are simulated by JMatPro software

and the heat treatment process parameters are optimized. The results show that the phase composition of 2324 aluminum alloy at room temperature is 88.02% α(Al)

7.28% S(Al2CuMg)

2.45% Al6Mn

1.35% Al2Cu

0.63% E(AlCrMgMn) and 0.27% Mg2Si

among which S phase is the main strengthening phase.The metastable phase of the alloy is S′ phase

Q′ phase and η′ phase

among which S′ phase is the main strengthening phase during the aging process.The TTT curve calculation show that during the heat treatment

the tip temperatures of GP zone

η′

S′

η(MgZn2) and S phase increase successively

which are 170℃

300℃

350℃

360℃ and 420℃ respectively

and the corresponding incubation times are 5.45s

40.91s

15.23s

920.62s and 305.83s respectively The CCT curve calculation shows that the critical cooling rates of GP zone

η′

S′

η(MgZn2) and S phase without precipitation during heat treatment are 0.95℃/s

1.72℃/s

5.22℃/s

0.16℃/s and 0.90℃/s respectively.When aging at 190℃

the precipitation amount of S′ phase is larger

and the complete aging time is shorter.When the aging time is 5~10h

the strengthening phase content is higher

and there is also a certain content for GP zone.Therefore

by the above results

the optimal heat treatment process can be obtained: the cooling rate of the cooling medium is greater than 5.22℃/s in the solid solution treatment

the solid solution transfer time of the sample is less than 5.45s

and the aging temperature and time are respectively set at 190℃ and 5~10h.