摘要
Continuous drive friction welding was employed to join the aeronautic aluminum alloy 2024.Parametric optimization and microstructural characterization were investigated.Results show that friction pressure is the most significant factor influencing the tensile strength of joints.To obtain a high joint efficiency,the combination of moderate friction pressure,less friction time and higher upset pressure is recommended.The optimized joint efficiency from Taguchi analysis reaches 92% of base metal.Under the optimized experimental condition,the interfacial peak temperature is calculated analytically in the range of 779-794 K,which is validated by experimental data.Fine recrystallized grains caused by the high temperature and plastic deformation are observed in the friction interface zone.The grain refinement is limited in the thermo-mechanically affected zone,where most of matrix grains are deformed severely.The extensive dissolution and limited re-precipitation of strengthening phases result in a lower microhardness in the friction interface zone than that in the thermo-mechanically affected zone.
开展航空用铝合金2024的连续驱动摩擦焊工艺优化试验,并表征焊接接头的显微组织演变。结果表明,摩擦压力是影响焊接接头抗拉强度的最显著因素,而采用适中的摩擦压力匹配较短的摩擦时间和较高的顶锻压力更易获取较高抗拉强度的接头。采用田口分析优化后的焊接工艺参数,焊后接头抗拉强度能够达到原始母材的92%。通过解析求解得到优化焊接工艺参数下焊接过程中摩擦界面的峰值温度处于779-794K,与试验测量结果吻合良好。由于高温和塑性变形的影响,摩擦界面的晶粒发生动态再结晶后尺寸明显细化。热影响区的晶粒细化有限,大部分原始晶粒受塑性流动影响发生变形。在摩擦阶段由于界面区域原始强化相发生固溶,且在随后冷却中二次析出不完全,最终导致摩擦界面的显微硬度降低。
基金
Project(51475196) supported by the National Natural Science Foundation of China
Project(2017ZX04004001) supported by the National Science and Technology Major Project on High-end Numerically Controlled Machine Tools and Basic Manufacturing Technology,China
