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采用拉伸试验、硬度测试、金相分析等方法测试和分析了7XXX铝合金经过热挤压、T6热处理后的强度、硬度和金相组织。研究了在不同温度下,变形次数(1～4次)对7XXX铝合金组织与性能的影响。研究表明:320℃时,7XXX铝合金晶粒的尺寸随变形次数的增加而变大,合金的硬度、强度随变形次数的增加而降低。这主要是因为变形而产生的形变内应力得到一定程度的释放,晶粒形核所需要的驱动力减少;480℃时,随着变形次数的增加,其硬度、强度增加。这主要是因为保温一定时间使得合金变软,不易发生动态再结晶。
Tensile test, hardness test and metallographic analysis were used to test and analyze the strength, hardness and microstructure of 7XXX aluminum alloy after hot extrusion and T6 heat treatment. The effect of deformation times (1 ~ 4 times) on microstructure and properties of 7XXX aluminum alloy at different temperatures was studied. The results show that the grain size of 7XXX aluminum alloy increases with the increase of the deformation times at 320 ℃, and the hardness and strength of the alloy decrease with the increase of deformation times. This is mainly due to deformation of the deformation caused by a certain degree of internal stress release, grain nucleation required to reduce the driving force; 480 ℃, with the increase in the number of deformation, the hardness and strength increased. This is mainly because the insulation for a certain period of time makes the alloy softer, less prone to dynamic recrystallization.