Al-Mg系铝合金超塑性薄壁管材

Superplasticity of Al-Mg aluminum alloys tube

采用熔铸—均匀化退火—挤压工艺研制Al-5.60Mg-0.30Zr-0.07Cr-0.16Mn(质量分数,%)合金管材。对该合金管材进行析出退火处理后,采用热旋—退火—冷旋工艺制备薄壁旋压管。采用金相显微镜、扫描电镜、拉伸性能测试等手段研究该铝合金旋压管冷变形态与完全再结晶退火态的组织与性能,测试其超塑性能,讨论其超塑性变形与断裂行为。研究结果表明,在Al-Mg铝合金中加入微量锆、铬、锰,可以促使试验合金中第二相颗粒弥散分布,减小后续加工的变形不均匀性;Al-5.6Mg-0.30Zr合金经析出退火—旋压变形后,于500℃退火1 h的再结晶退火组织晶粒平均粒径小于10μm。

The extruded tube of Al-5.6Mg-0.30Zr-0.07Cr-0.16Mn （mass fraction, %） alloy was prepared in a smelting-casting-homogenizing-extruding process. The tube samples were spun into thin tube via combination of warm-spinning-annealing-cold-spinning process. Microstructures and tensile properties of the cold-spun pipes and their fully recrystallization annealed alloys were characterized by means of optical microscopy, scanning electron microscopy and tensile test. Superplastic tensile test was carded out to study superplastic deforming and fracturing behaviour of the cold-rolled sheets and cold-spun pipes. The results show that precipitating annealing treatment can improve distributing uniformity of the second phase particles in the testing alloy, minish plastically deforming heterogeneity of the sequential cold-rolling or cold-spinning process, and so the ultra-fine equiaxed grain structure with uniform distribution state can be obtained via a combination of warm-deforming-annealing-cold-deforming process, which can meet the microstructural request for high temperature superplastic deformation.