(1. 西北工業(yè)大學(xué) 凝固技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，西安 710072；
2. 浙江巴頓焊接技術(shù)研究院，杭州 311200；
3. 南昌航空大學(xué) 輕合金加工科學(xué)與技術(shù)國(guó)防重點(diǎn)學(xué)科實(shí)驗(yàn)室，南昌 330063；
4. 中國(guó)商飛上海飛機(jī)制造有限公司，上海 200436)
摘 要: 采用靜軸肩攪拌摩擦增材制造方法制備了2024鋁合金增材塊體，對(duì)塊體進(jìn)行了后續(xù)熱處理，用OM觀察了顯微組織，用XRD及TEM分析了第二相含量及形貌特征。結(jié)合顯微硬度，分析了熱處理對(duì)增材塊體組織及性能的影響。結(jié)果表明：增材態(tài)塊體組織為再結(jié)晶的細(xì)小等軸晶，沿增材厚度方向由底部向頂部晶粒尺寸逐漸減小，第二相含量逐漸增多，顯微硬度逐漸增大，最大硬度值為99 HV，平均硬度值為86.5 HV。經(jīng)熱處理后，增材塊體中重新析出大量S′相，析出過(guò)程為α(Al)→S′(Al2CuMg)；第二相呈棒狀和橢球狀，彌散分布于α(Al)基體中，新析出的S′相與基體呈共格關(guān)系；增材塊體的顯微硬度明顯增大，且沿厚度方向分布均勻，平均硬度值達(dá)135 HV。顯微硬度明顯增大的原因是熱處理使增材塊體中析出了細(xì)小的第二相，產(chǎn)生了第二相強(qiáng)化。
關(guān)鍵字: 熱處理；靜軸肩FSAM；鋁合金；顯微組織；第二相
（1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. Zhejiang EO. Paton Welding Technology Research Institute, Hangzhou 311200, China;
3. National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China;
4. COMAC Shanghai Aircraft Manufacturing Co., Ltd., Shanghai 200436, China）
Abstract:The 2024 aluminum alloy additive bulk was fabricated by the stationary shoulder friction stir additive manufacturing. Heat treatment was conducted on the addictive bulk. The microstructure was observed by OM. The content and morphology of the second phase were analyzed by XRD and TEM respectively. The effect of heat treatment on microstructure and properties of the additive bulk was analyzed under the consideration of microhardness. The results show that the re-crystallized fine equiaxed grains appear in the additive bulk sample. The grain size gradually decreases from the bottom to the top. While the content of the precipitates and microhardness gradually increase from the bottom to the top. The maximum microhardness and average microhardness values are 99 HV and 86.5 HV respectively. After heart treatment, a large number of S′ phases with rod and ellipsoidal shape re-precipitated, and dispersely distribute in the α(Al) matrix, the relationship between precipitates and the matrix is coherent with each other. The process precipitation of the precipitates is α(Al)→S′(Al2CuMg). More homogeneous and significantly increased microhardness are acquired, the average microhardness value is 135 HV, which should be attributed to the precipitation of a fine second phase, inducing in the precipitation strengthening.
Key words: heat treatment; stationary shoulder FSAM; aluminum alloy; microstructure characteristic; Precipitates
