合金成分变化对搅拌摩擦焊接力学性能的影响

Effect of chemical compositions on mechanical properties of friction stir welds

建立搅拌摩擦焊接的移动热源模型和析出相演化计算模型,采用数值模拟方法计算在搅拌摩擦焊接过程中析出相的变化、焊后力学性能,以及不同铝合金成分变化时,对搅拌摩擦焊接构件力学性能的影响,并与试验相比验证模型的正确性。结果表明:根据析出相演化将5种铝合金分为两类,相同位置处AA6005、AA6063、AA6060的平均粒子半径大小接近,而AA6061、AA6082的平均半径相似;两组铝合金相比,平均粒子半径以及粒子数有明显差异,对硬度值产生明显影响;随着与焊缝中心线的距离增加,5种合金的平均粒子半径间的差值逐渐缩小,由于AA6061和AA6082的粒子数较大,导致与AA6005、AA6063、AA6060的硬度值存在明显差异。

Moving heat source model and precipitate evolution model are established to calculate the variations of precipitates in friction stir welding process. Based on the above computational results,the post weld mechanical properties can be further calculated. The comparison of numerical and experimental results can show the validity of the models. The cases with chemical compositions variations are further calculated to study the effects on mechanical properties. Results indicate that the selected five cases of alloys can be divided into two groups according to the precipitate evolutions. The average particle radius of the three aluminum alloys AA6005,AA6063,AA6060 at the same position are basically similar,and the average radius of the two alloys AA6061 and AA6082 are also similar. However,compared with the two sets of aluminum alloys,the average particle radius and the number of particles have significant differences,and these differences have a significant impact on the hardness value. As the distance from the centerline of the weld increases,the difference between the average particle radii of the five alloys gradually decreases. However,due to the high particle number density of AA6061 and AA6082,their hardness value are significantly different to the hardness values of AA6005,AA6063,and AA6060.