在高压扭转大塑性变形及时效过程中6201铝合金组织和硬度的变化规律

Evolution of Microstructure and Hardness of 6201 Aluminum Alloy During High-Pressure Torsion Severe Plastic Deformation and Aging

在室温下对挤压态6201铝合金进行不同转数(1,2,5,10,20 r)的高压扭转变形以及175℃保温不同时间(10,60 min)的时效处理,研究了变形及时效过程中组织和硬度的变化规律。结果表明:随着高压扭转转数的增加,晶粒尺寸由微米级细化至亚微米级,晶粒趋向于变为等轴晶,合金硬度升高;当高压扭转转数大于10 r后,合金组织稳定,晶粒尺寸约为183 nm,硬度基本保持不变。随着时效时间的延长,高压扭转10 r合金的晶粒逐渐长大和粗化,时效60 min后,次中心位置平均晶粒尺寸约为523 nm;合金发生明显的时效软化,随着时效时间的延长,合金硬度降低。

The high-pressure torsion deformation at room temperature of extruded 6201 aluminum alloy with different revolutions(1,2,5,10,20 r)and the aging treatment at 175℃for different time intervals(10,60 min)were carried out.The revolution of microstructure and hardness during deformation and aging was studied.The results show that with the increase of high-pressure torsion revolution,the grain size was refined from micrometer to submicrometer,the grains tended to become equiaxed grains,and the hardness of the alloy increased.When the high-pressure torsion revolution was greater than 10 r,the alloy microstructure was stabilized,the grain size was about 183 nm,and the hardness was basically unchanged.With the extension of aging time,the grains of the alloy by high pressure torsion of 10 r gradually grew and were coarsened,and after aging for 60 min,the average grain size of the sub-center position was about 523 nm;the alloy underwent obvious aging softening,and the hardness of the alloy decreased with increasing aging time.