温轧工艺对6061铸轧板材显微组织和力学性能影响

采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)及万能拉伸机等研究了不同温轧温度及累积压下率对双辊铸轧6061铝合金板材组织性能的影响。结果表明,6061铝合金铸轧板组织主要由耐热相Al0.7Fe3Si0.3、Al9Fe0.84Mn2.16Si及少量强化相Mg2Si组成。合金中第二相随温轧道次递增逐渐由网格状、片状转变为沿轧制方向的线条状,最终变为细小的颗粒状。温轧后,有新的析出相Al0.5Fe3Si0.5产生,且Mg2Si相的数量增多。6061铝合金铸轧板较为适宜的温轧工艺为:370℃轧制+80%累积压下率,此时铸轧板热处理后的屈服强度、抗拉强度和伸长率分别88.48 MPa,318.76 MPa和20.53%。

Effect of warm rolling on microstructure and mechanical properties of 6061 aluminum alloy cast-rolled sheet

The effects of different warm rolling temperature and cumulative reduction rate on microstructure and properties of 6061 aluminum alloy sheet were studied by means of optical microscope(OM), scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffractometer(XRD) and universal stretching machine. The results show that the microstructure of the 6061 aluminum alloy cast-rolled sheet is mainly composed of heat resistant phase Al0.7Fe3Si0.3, Al9Fe0.84Mn2.16Si and a small amount of strengthened phase Mg2Si. With the increase of warm rolling pass, the second phase of the alloy gradually changes from mesh and sheet shape to line shape along the rolling direction, and finally to fine granular shape. After warm rolling, new precipitated phase Al0.5Fe3Si0.5 is observed, and the amount of the Mg2Si phase increases. The optimal warm rolling process of the 6061 aluminum alloy cast-rolled sheet is as follows: rolling at 370 ℃+80% cumulative reduction rate, and the yield strength, tensile strength and elongation of the cast-rolled sheet after heat treatment are 88.48 MPa, 318.76 MPa and 20.53%, respectively.