(1. 南昌航空大學 輕合金加工科學與技術(shù)國防重點學科實驗室，南昌 330063；
2. 中國商飛上海飛機制造有限公司，上海 200436)
摘 要: 采用靜軸肩攪拌摩擦增材制造(FSAM)方法制備2024鋁合金增材，用OM及SEM觀察增材的顯微組織，用XRD及TEM分析增材的第二相含量及形貌特征，結(jié)合增材的顯微硬度，研究靜軸肩FSAM材料的強化機理。結(jié)果表明：增材組織為再結(jié)晶的細小等軸晶，晶粒尺寸由底部向頂部逐漸減小，增材中的第二相發(fā)生重溶，含量較基材明顯減少，且第二相含量由底部向頂部逐漸增多。增材的顯微硬度由底部向頂部逐漸增大，最大硬度值為99HV，低于基材的，這是由于FSAM使增材中的第二相發(fā)生重溶，且第二相與基體的共格關(guān)系變化，共格應變減小，增材組織發(fā)生過時效。
關(guān)鍵字: 鋁合金；靜軸肩FSAM；第二相；組織特征
（1. National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China;
2. COMAC Shanghai Aircraft Manufacturing Co., Ltd., Shanghai 200436, China）
Abstract:The stationary shoulder friction stir additive manufacturing(FSAM) technology was used for additive manufacturing of 2024 aluminum alloy, the microstructure of the additive material(AM) was observed by OM and SEM, the content and morphological characteristics of the precipitated phase in the AM were analyzed by XRD and TEM. Combined with the microhardness of the AM, the strengthening mechanism of the stationary shoulder FSAM on 2024 aluminum alloy was studied. The results show that the microstructure of AM is a re-crystallized fine equiaxed grain, the grain size of the AM gradually decreases from the bottom to the top. The precipitated phase in the AM is re-dissolved, the content is significantly reduced relative to the base material(BM). The content of the precipitated phase gradually increases from the bottom to the top. The microhardness of the AM increases gradually from the bottom to the top, the maximum hardness is 99HV, still lower than that of the BM. This is because the precipitated phase in the AM is re-dissolved by the FSAM, and the coherent strain of the precipitated phase and the matrix gradually disappears, resulting in over-aging of the AM microstructure.
Key words: aluminum alloy; stationary shoulder FSAM; precipitated phase; microstructure characteristic
