温锻对2A12铝合金锻件组织和性能的影响

Influence of warm forging on microstructure and properties for 2A12 aluminum alloy forgings

通过OM、SEM、EBSD和室温力学性能检测手段,对热锻、温锻、T6热处理后的2A12铝合金锻件的组织和性能进行了观察和分析。研究结果表明:温锻时的畸变能大,提高了T6热处理态2A12铝合金锻件的再结晶程度,心部高向的断裂方式由脆性断裂转变为"脆性+穿晶韧窝"混合型断裂,心部高向伸长率得到大幅度提高,且波动性减小。在20%变形量下温锻时,心部高向伸长率最优,提高幅度为29.2%。在相同变形量下温锻时,纤维状挤压晶粒以(110)和(100)为主,小角度晶界更多,晶界界面能低,再结晶所需的驱动力更大,纤维状挤压晶粒更难发生再结晶。在10%变形量下温锻时,挤压纤维状晶粒发生少量再结晶,在20%~30%变形量下温锻时,纤维状挤压晶粒发生完全再结晶,组织更加均匀,各向异性变小,不同位置的力学性能波动性减小。

The microstructures and properties of 2A12 aluminum alloy forgings in T6 heat treated state after hot forging and warm forging were observed and analyzed by the methods of OM,SEM,EBSD and mechanical properties testing at room temperature.The research results show that the distortion energy of warm forging is larger,which improves the recrystallization degree of 2A12 aluminum alloy forgings in T6 heat treated state,the fracture mode of core in high direction changes from brittle fracture to mixed fracture of’brittle+transcrystalline dimple’,and the elongation of core in high direction is greatly improved with the reduced volatility.The elongation of core in high direction is the best during the warm forging with 20%deformation,and the increased range is up to 29.2%.In the case of warm forging with the same deformation,the fibrous extruded grains are mainly(110)and(100),with more small-angle grain boundaries and lower grain boundary interface energy,which makes the driving force required for recrystallization larger,so it is more difficult for the fibrous extruded grains to recrystallize.During the warm forging with 10%deformation,a small amount of fibrous extruded grains are recrystallized,and during the warm forging with 20%-30%deformation,the fibrous extruded grains are completely recrystallized with more uniform microstructure,and the anisotropy becomes smaller,so the fluctuation of mechanical properties at different positions is reduced.