Development of high strength Al―Mg―Si AA6061 alloy through cold rolling and ageing
Development of high strength Al―Mg―Si AA6061 alloy through cold rolling and ageing
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DOI：
10.1016/j.msea.2009.03.077
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发表时间：
2009-07
期刊：
影响因子：
6.4
通讯作者：
V. L. Niranjani;K. C. Kumar;V. Sarma
中科院分区：
文献类型：
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作者：
V. L. Niranjani;K. C. Kumar;V. Sarma
超细晶（ufg）和纳米晶（nc）材料由于在屈服强度和断裂强度方面的显著改善而被广泛研究。然而，在这些材料中实现合理的延展性仍然是一个挑战。最近的研究结果表明，高强度和延展性的组合，可以实现在沉淀硬化合金通过严重的塑性变形，然后退火/时效处理。在目前的工作中，固溶板的Al-Mg-Si合金（改性AA 6061合金）进行严重的冷轧在室温和液氮温度下的真应变1.6。将轧制的片材老化以诱导沉淀。用CALPHAD计算了上述合金的平衡第二相分布。采用差示扫描量热仪（DSC）、X射线衍射仪（XRD）、透射电子显微镜（TEM）、硬度和拉伸试验对轧制和时效样品进行了分析。从DSC测量获得的储能被发现是独立的轧制温度。在两种轧制条件下，S {123}<$634 <$10取向的体积分数都占主导地位（约40%）。冷轧（CR）和室温轧制（RT）试样时效后，强度和塑性同时得到改善。透射电子显微镜分析显示在CR和RT条件下的位错细胞结构。第二相的分析揭示了精细的球形富Mn沉淀物（最有可能是Al 6 Mn）老化后。
Ultrafine grained (ufg) and nanocrystalline (nc) materials are widely researched due to significant improvements in yield and fracture strength. However, achieving a reasonable ductility in these materials is still a challenge. Recent results have shown that the combination of high strength and ductility could be achieved in precipitation hardening alloys through severe plastic deformation followed by annealing/ageing treatments. In the present work, the solutionised plates of an Al–Mg–Si alloy (modified AA6061 alloy) were subjected to severe cold rolling at room and liquid nitrogen temperatures to a true strain ∼1.6. The rolled sheets were aged to induce precipitation. The equilibrium second phase distribution for the above alloy was calculated using CALPHAD. The rolled and aged samples were analysed using differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), hardness and tensile tests. The stored energy obtained from DSC measurements was found to be independent of the rolling temperature. The volume fraction of S {123} 〈634〉 orientation is predominant (∼40%) in both the rolling conditions. The strength and ductility were simultaneously improved following ageing of the cryorolled (CR) and room temperature rolled (RT) samples. Transmission electron microscopy analysis revealed dislocation cell structures in the CR and RT conditions. Analysis of second phases revealed fine spherical Mn rich precipitates (most likely Al6Mn) following ageing.