Cr元素及不同工艺对Al-Mg-Si合金组织和性能的影响

Influence of Cr element and different processes on microstructure and properties of Al-Mg-Si alloy

通过万能拉伸试验机、金相显微镜、扫描电镜等试验设备分析Cr元素及不同工艺对Al-Mg-Si合金力学性能和组织的影响。结果表明,在添加Cr元素后,抗拉强度、屈服强度增加,抗拉强度的增加幅度较为明显。当提高热轧卷取温度(360℃→380℃)和预时效温度(70℃→80℃)、改变淬火方式(空冷→水冷)时,抗拉强度和屈服强度明显增加,约增加了13 MPa。Cr元素对弥散相尺寸影响不大,其会使弥散相数量增多。热轧卷取温度由300℃升高至360℃时,平均晶粒尺寸由25.96μm降低至23μm;当热轧卷取温度升高至380℃时,晶粒发生粗化。元素添加对第二相种类影响也较大,添加Cr元素后,AlFeMnSi相转变为Al(FeMnCr)Si相,黑色的第二相为Mg_(2)Si相,其数量和尺寸会随着Cr元素的增多而减少。

The influences of Cr elements and different processes on the mechanical properties and microstructure of Al-Mg-Si alloy were analyzed by universal tensile testing machine,metallographic microscope and scanning electron microscope.The results show that after adding Cr element,the tensile strength and yield strength increase,and the increase of tensile strength is more significant.By increasing the hot rolling coiling temperature(360℃380℃)and pre-aging temperature(70℃80℃),and changing the quenching method(air cooling water cooling),the tensile strength and yield strength is increased significantly,by about 13 MPa.Cr element has little effect on the size of dispersed phase,but it increases the number of dispersed phases.When the hot rolling coiling temperature increases from 300℃to 360℃,the average grain size decreases from 25.96μm to 23μm.When the hot rolling temperature rises to 380℃,the grain coarsening occurs.The addition of elements also has a significant impact on the type of second phase.After adding Cr element,AlFeMnSi phase transforms into Al(FeMnCr)Si phase,the black second phase is Mg_(2) Si phase,and its quantity and size decrease with the increasing of Cr element.