对航空用铝合金A7075-T651的搅拌摩擦焊接头的母材、焊核区和热影响区的疲劳裂纹扩展速率(da/dN)进行了试验研究。疲劳裂纹扩展试验采用CT(紧凑拉伸)试样,在810 Material Test System试验机上进行。用递增多项式法求得疲劳裂纹扩展速率(...对航空用铝合金A7075-T651的搅拌摩擦焊接头的母材、焊核区和热影响区的疲劳裂纹扩展速率(da/dN)进行了试验研究。疲劳裂纹扩展试验采用CT(紧凑拉伸)试样,在810 Material Test System试验机上进行。用递增多项式法求得疲劳裂纹扩展速率(da/dN)和(ΔK),并分别将母材、焊核区和热影响区同一组试样的(da/dN)和(ΔK)数据点合在一起进行了整体回归分析。试验中得到了以Paris公式表达的铝合金A7075-T651母材、焊核区、热影响区da/dN与ΔK的关系式。结果表明,热影响区疲劳裂纹扩展速率高于母材和焊核区,是该合金搅拌摩擦焊接头最薄弱的区域。展开更多
The effects of applying an electromagnetic interaction of low intensity (EMILI) on the microstructure and corrosion resistance of 7075-T651 Al alloy plates (13 mm in thickness) during modified indirect electric arc (M...The effects of applying an electromagnetic interaction of low intensity (EMILI) on the microstructure and corrosion resistance of 7075-T651 Al alloy plates (13 mm in thickness) during modified indirect electric arc (MIEA) welding were investigated. The welding process was conducted in a single pass with a heat input of ~1.5 kJ/mm. The microstructural observations of the welds were correlated with the effect of EMILI on the local mechanical properties and the corrosion resistance in natural seawater by means of microhardness measurements and electrochemical impedance spectroscopy, respectively. Microstructural characterization of the welds revealed a grain refinement in the weld metal due to the electromagnetic stirring induced by EMILI of 3 mT during welding. In addition, observations in the scanning electron microscope showed that the precipitation of Cu-rich phases and segregation of eutectics were reduced in the heat affected zone (HAZ) also as an effect of EMILI. The high corrosion dissolution of the 7075-T651 welds in natural seawater and the extent of overaging in the HAZ were reduced when welding with EMILI of 3 mT. Thus, EMILI along with the MIEA technique may lead to welded joints with better microstructural characteristics, improved mechanical properties in the HAZ and reduced electrochemical activity.展开更多
文摘对航空用铝合金A7075-T651的搅拌摩擦焊接头的母材、焊核区和热影响区的疲劳裂纹扩展速率(da/dN)进行了试验研究。疲劳裂纹扩展试验采用CT(紧凑拉伸)试样,在810 Material Test System试验机上进行。用递增多项式法求得疲劳裂纹扩展速率(da/dN)和(ΔK),并分别将母材、焊核区和热影响区同一组试样的(da/dN)和(ΔK)数据点合在一起进行了整体回归分析。试验中得到了以Paris公式表达的铝合金A7075-T651母材、焊核区、热影响区da/dN与ΔK的关系式。结果表明,热影响区疲劳裂纹扩展速率高于母材和焊核区,是该合金搅拌摩擦焊接头最薄弱的区域。
文摘The effects of applying an electromagnetic interaction of low intensity (EMILI) on the microstructure and corrosion resistance of 7075-T651 Al alloy plates (13 mm in thickness) during modified indirect electric arc (MIEA) welding were investigated. The welding process was conducted in a single pass with a heat input of ~1.5 kJ/mm. The microstructural observations of the welds were correlated with the effect of EMILI on the local mechanical properties and the corrosion resistance in natural seawater by means of microhardness measurements and electrochemical impedance spectroscopy, respectively. Microstructural characterization of the welds revealed a grain refinement in the weld metal due to the electromagnetic stirring induced by EMILI of 3 mT during welding. In addition, observations in the scanning electron microscope showed that the precipitation of Cu-rich phases and segregation of eutectics were reduced in the heat affected zone (HAZ) also as an effect of EMILI. The high corrosion dissolution of the 7075-T651 welds in natural seawater and the extent of overaging in the HAZ were reduced when welding with EMILI of 3 mT. Thus, EMILI along with the MIEA technique may lead to welded joints with better microstructural characteristics, improved mechanical properties in the HAZ and reduced electrochemical activity.
