均匀化时间对Al-Mn合金组织的影响

采用扫描电镜、能谱分析和显微硬度研究了一种Al-Mn合金的铸态试样在610℃均匀化处理不同时间时的组织演化和显微硬度变化。实验结果表明:在610℃均匀化退火4 h时,合金内不连续网状枝晶已经溶解得比较充分,骨骼状的化合物也转化为块状;在一定时间内,随着均匀化处理时间的延长,β-Al6(MnFe)相向α-Al(MnFe)Si相转变量增多。由微观组织转变和显微硬度结果表明,该合金在610℃合理的均匀化处理时间为10 h左右,这与采用均匀化动力学方程得到的结论基本一致。在该参数下,合金内化合物尺寸最小且分布弥散,α-Al(MnFe)Si相在化合物中所占比例明显增多。

Effect of Homogenization Treatment on Microstructural Evolution of Al-Mn Alloy

The evolution of the microstructure and microhardness of a certain kind of Al-Mn alloies during homogenization treatment at 610°C is investigated by scanning electron microscopy,energy depressive spectroscopy and microhardness measurement.The results show that the discontinuous dendrite dissolves adequately after homogenization at 610 ℃ for 4 h.With the increase of annealing time,skelecton-like shaped phase transforms into block-like shape gradually,and the ratio of the transfor-mation from β-Al6(MnFe) phase to α-Al(MnFe)Si phase also increases.Furthermore,the proper homogenizing process for this Al-Mn alloy is at 610 ℃ for 10 h,which is in agreement with the results from the homogenizing kinetic equation.Under this process,most of the particles in this alloy become smaller and good dispersed phases,and the ratio of α-Al(MnFe)Si phase increases obviously.