升温速率对1933铝合金铸锭均匀化组织的影响

摘要

The effects of heating rate on the homogenization microstructures of 1933 aluminum alloy ingot were investigated by optical microscopy, scanning electron microcopy, energy dispersive spectrometry, transmission electron microcopy and X-ray diffractometry. The results show that the as-cast microstructures involve eutectic (α(Al)+η(MgZn2)),AlZnCu and AlCuFe phases. The lamellar eutectic is dissolved through homogenization, and the particles presented in the alloy ingot are AlZnCu and AlCuFe phases. Compared with the fast-heating rate treatment, the slower apparently leads to a higher density of fine Al3Zr dispersoids, the dimension of the dispersoids decreases from 15 nm to 10 nm, the width of dispersoid-free-zone (DFZ) decreases from 3-5 μm to 0.5 μm, and the number density of Al3Zr particle in the center in the grains increases from 120/μm3 to 400/μm3.%采用光学显微镜、扫描电镜、能谱分析、透射电镜和X线衍射分析等试验手段,研究升温速率对1933铝合金铸锭均匀化显微组织的影响.研究结果表明;合金铸态中主要存在α(Al)+η(MgZn2)非平衡共晶组织、AlZnCu相和AlCuFe相;均匀化处理后共晶组织被消除,η相溶解,合金中残留有AlZnCu相和AlcuFe相;合金经465℃/24 h、升温速率为200℃/h均匀化处理后,晶界附近存在一个明显的无A13Zr粒子析出带(DFZ),宽度为3～5 μm,晶粒中心Al3Zr粒子的密度较小,约为120个/μm3,粒子尺寸较大,半径约为15 nm;均匀化慢速升温(20℃/h)将无弥散析出区(DFZ)的宽度减小到0.5μm,晶内Al3Zr粒子分布更弥散细小,粒子半径为10 nm,粒子密度约为400个/μm3.