The 7050 aluminum alloy orifice plate is extruded and strengthened by the cold expansion process of slotted bushing holes. A three-dimensional finite element model was established for cold expansion strengthening of holes, and the residual stress distribution of 7050 aluminum alloy orifice plates is studied after cold expansion. The influence of different relative extrusion amounts and different sample thicknesses on the residual stress around the sample hole was analyzed, and the relationship between the extrusion amounts and the thicknesses of the substrate and the residual stress was obtained by analysis. The research results indicate that the cold expansion process of slotted bushing holes can enhance the residual stress distribution around the hole and form a strong residual stress layer. As the amounts of extrusion increase, the residual stress tends to increase, reaching the maximum when the amounts of extrusion are 4%. The residual stress on the surface of the extrusion inlet increases with the increase in the thickness of the substrate. Within the range of 3%-4% of the extrusion amounts, with the continuous increase of the extrusion amounts, the fatigue life has been substantially enhanced, and the number of fatigue life is more than 3 times that of the empty plate fatigue test.

中文翻译：

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7050铝合金孔的冷胀强化：组织、残余应力和疲劳寿命

7050铝合金孔板采用开槽衬套孔冷扩工艺挤压强化。建立了孔冷扩强化的三维有限元模型，研究了7050铝合金孔板冷扩后的残余应力分布。分析了不同相对挤压量和不同样品厚度对样品孔周围残余应力的影响，分析得出挤压量与基板厚度及残余应力的关系。研究结果表明，开槽衬套孔的冷扩工艺可以增强孔周围的残余应力分布，形成较强的残余应力层。随着挤出量的增加，残余应力有增加的趋势，在挤压量为4%时达到最大值。挤压入口表面的残余应力随着基材厚度的增加而增加。在挤压量的3%-4%范围内，随着挤压量的不断增加，疲劳寿命得到了大幅度的提高，疲劳寿命次数是空板疲劳试验的3倍以上。