中间退火温度对6016铝合金组织及性能的影响

Effect of intermediate annealing temperature on microstructure and properties of 6016 aluminum alloy

采用金相显微镜、扫描电镜、X射线衍射仪和力学性能试验机对6016铝合金不同中间退火温度下的组织及性能演变规律进行分析。结果表明,在不同退火温度下,6016铝合金的力学性能变化不大,但包边因子f和Δr值有显著变化,360℃中间退火温度下f(0.60)和Δr值(0.24)小于410℃中间退火温度f(0.75)和Δr值(0.28),说明360℃中间退火温度的包边性能优于410℃中间退火温度。随着退火温度的升高,表层晶粒尺寸和晶界析出物Mg_(2)Si相尺寸增大,最大Mg_(2)Si相尺寸从1.41μm增加到2.09μm,大部分Mg_(2)Si相形态由圆润状变为长条状。360℃中间退火温度下Cube和R织构占比分别为12.04%、5.37%,410℃中间退火温度下Cube和R织构占比分别为14.25%、3.43%,其中,360℃中间退火温度下R织构占比较高,使Δr值降低,有利于提高包边性能。410℃中间退火温度下,6016铝合金的裂纹扩展较360℃的快,其与晶界上粗大的Mg_(2)Si相有关。

Microstructure and properties evolution of 6016 aluminum alloy intermediate annealed at different temperatures were analyzed using metallographic microscopy,scanning electron microscopy,X⁃ray diffraction and mechanical performance testing machines.The results show that under different annealing temperatures,the mechanical properties of the 6016 aluminum alloy do not change much,but hemming factor f andΔr value change significantly.The values of f(0.60)andΔr(0.24)at the intermediate annealing temperature of 360℃are lower than the values of f(0.75)andΔr(0.28)at the intermediate annealing temperature of 410℃,indicating that the hemming property at the intermediate annealing temperature of 360℃is better than that at the intermediate annealing temperature of 410℃.As the annealing temperature increases,the surface grain size and grain boundary precipitate Mg_(2)Si phase size also increase,the maximum size of Mg_(2)Si phase increases from 1.41μm to 2.09μm,and the morphology of most Mg_(2)Si phase change from rounded to elongated.The proportion of Cube texture and R texture at the intermediate annealing temperature of 360℃is 12.04%and 5.37%,respectively.The proportion of Cube texture and R texture at the intermediate annealing temperature of 410℃is 14.25%and 3.43%,respectively.Among them,the proportion of R texture at the intermediate annealing temperature of 360℃is higher,which reduces theΔr value and is conducive to improving the hemming property.The crack propagation of the 6016 aluminum alloy at the intermediate annealing temperature of 410℃is faster than that at the intermediate annealing temperature of 360℃,which is related to the coarse Mg_(2)Si phase on the grain boundaries.