Mn Content And Thermomechanical Processing Of 2519a Aluminum Alloy Microstructure And Properties

This paper combines "aluminum alloy Impact Dynamic behavior of the structure and characteristics of micro-down" which is belong to the 973 Project "efficient utilization of high-performance aluminum and aluminum resources in basic research". By hardness testing, x-ray diffraction (XRD) analysis, the tensile test,metallographic examination, scanning electron microscopy (SEM), transmission electron microscopy (TEM), method, the content of element Mn and thermomechanical treatment affect 2519A aluminum alloy on the microstructure and mechanical properties of the experimental results showed1. The element Mn puts effect on the age hardening behavior of 2519A aluminum alloy, the 2519A aluminum alloy with15% pre-deformation decreases the peak micro-hardness from145HV to 132HV when Mn content from 0.29% increased to 0.45%; Accordingly, the time reaching to the peak is short from 9h to 6h.2. The mechaical properties of 2519A aluminum alloy containing 0.29% Mn areσb=533MPa,σa0.2=495MPa,8=11.8%, after solution treatment at 525℃for 1.5h, water-cooling,15% pre-deformation, spent 9 hours at 165℃.3. The observation of TEM showed that:after solution treatment at 525℃for 1.5h, water-cooling,15% pre-deformation, spent 9 hours at 165℃, the 2519A aluminum alloy containing 0.29% Mn precipitate a large amount of even and fineθ' phase in intergranular, its size is about 40～50nm; whileθphase on grain boundaries was distributed and precipitation-free zone was narrow and discontinuous.4. To obtain better performance, including 0.29% Mn 1# alloy for the thermomechanical treatment orthogonal test and three levels of three factors orthogonal table L9 (33), orthogonal experiment results show: the best thermomechanical treatments process of the 2519A aluminum alloy containing 0.29% Mn are:solution treatment at 525℃for 1.5h, 50% pre-deformation and aging at 140℃for 6 hours, the mechaical properties areσb=551MPa,σ0.2=507.7MPa,δ=7.8%. 5. The observation of TEM showed that:after solution treatment at 525℃for 1.5h, water-cooling,50% pre-deformation, including 0.29% Mn 2519A aluminum alloy priority nucleation cell in the dislocation cell walls, precipitate finedθ' phase in intergranular. Along with the the extension of ageing time, theθ' precipitation phase increase gradually and grew up, artificial aging at 190℃for 3h, theθ' phase in intergranular precipitate in uniform dispersion distribution.6. After solution treatment at 525℃for 1.5h, water-cooling,80% pre-deformation, the 2519A aluminum alloy age at less than 200℃, the main strengthening is deformation hardening, the effect of precipitation hardening is not obvious.