(1. 沈陽航空航天大學航空航天工程學部，沈陽 110136；
2. 北京航空航天大學機械工程與自動化學院，北京100191)
摘 要: 以LY12鋁合金為研究對象，對常規(guī)攪拌頭作用下的回填式攪拌摩擦點焊的材料流動規(guī)律進行數(shù)值模擬，并利用焊點的宏觀形貌與顯微組織進行試驗驗證；討論不同攪拌頭形狀對材料流動行為的影響。結(jié)果表明：材料的高速流動區(qū)域主要位于套筒內(nèi)外壁附近；流動速度值在外壁凹槽處出現(xiàn)最大值，且隨著離套筒壁距離的增加而減小。流動規(guī)律的模擬結(jié)果由位于焊點中心的中間較寬、兩端較窄的韌帶與焊點內(nèi)部不同區(qū)域晶粒的不同所證實。從減小焊點內(nèi)韌帶寬度的角度考慮，雙凹槽攪拌頭優(yōu)于常規(guī)攪拌頭、小槽寬攪拌頭和大直徑攪拌頭。
關鍵字: 回填式攪拌摩擦點焊；攪拌頭形狀；數(shù)值模擬；材料流動
（1. Faculty of Aerospace Engineering, Shenyang Aerospace University, Shenyang 110136, China;
2. School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China）
Abstract:Choosing LY12 aluminum alloy as the research object, the material flow behavior of friction spot welding (FSpW) using conventional tool was simulated and verified by macrostructure and microstructure of welding spot. Meanwhile, the effects of tool geometries on material flow behavior during FSpW process were mainly discussed. The results show that the material near the inner and outer walls of sleeve attains high flow velocity. The maximum flow velocity appears in the groove region of the outer wall. And the velocity decreases as the distance from the walls of the sleeve becomes bigger. Bonding ligament with bigger width in the center and smaller width in two ends and different microstructures in different regions agree with the simulation results. From the viewpoint of decreasing the width of the bonding ligament, the double groove tool is better than the conventional tool, small width groove tool and big diameter tool.
Key words: refill friction stir spot welding; tool geometry; numerical simulation; material flow
