本文選題：鋁合金多層結構　切入點：釬焊　出處：《南京理工大學》2017年碩士論文

【摘要】：目前,國內外雷達天線和散熱器廣泛采用鋁合金薄壁復雜多層結構。鋁合金多層結構具有形狀復雜、通道壁薄、焊接面狹窄、尺寸形位精度要求高及制造難度大的特點,所以鋁合金多層結構普遍存在焊接質量不穩(wěn)定、成品率不高的問題。本文本文采用了釬焊、釬接-擴散復合焊接和擴散焊方法連接鋁合金多層結構,通過研究焊接接頭的界面組織結構,分析了不同工藝參數(shù)對接頭界面、力學性能及變形量的影響,并通過ANSYS有限元分析軟件,從而有效地指導了控制零件焊接變形的試驗,最終獲得了比較理想的焊接接頭。采用Al-Si-Mg釬料對3A21鋁合金多層結構進行了釬焊試驗,在釬焊溫度610℃,保溫時間10min條件下獲得最佳接頭,強度可達72 MPa。采用Al-Si-Mg釬料對3A21鋁合金多層結構進行了釬接-擴散復合焊接試驗,在釬焊溫度610℃,保溫時間10 min,擴散焊溫度560℃,壓力0.5 MPa,擴散時間60 min下,獲得理想接頭,強度達到81 MPa。由于釬焊后的擴散焊使得釬焊中容易出現(xiàn)的未焊合和空洞等缺陷得以消除,元素擴散更充分,因此釬接-擴散復合焊接所得接頭質量明顯好于釬焊接頭。對3A21鋁合金多層復雜結構焊接接頭焊縫進行了EDS分析,兩種方法的釬料與母材的元素均均勻擴散,且釬接-擴散復合焊接元素擴散更均勻。焊縫都主要包括蜂窩狀的Al基體、塊狀富Si相和初晶Si等。另外還出現(xiàn)Mg和Si形成Mg2Si強化相,提高了接頭性能。采用直接擴散焊焊接了 6061鋁合金多層結構,在焊接溫度560℃,焊接壓力為4 MPa,保溫時間為60 min下所得的最佳接頭強度達到140 MPa;加Al-Si中間層擴散焊,在焊接溫度為580℃,焊接時間為30min,焊接壓力2MPa,焊接溫度為520℃,焊接時間為60min,焊接壓力為1MPa下所得接頭具有更好的接頭質量和更高的接頭強度,強度達到150 MPa。對6061鋁合金多層復雜結構擴散連接接頭焊縫進行了元素與組織分析,焊縫都主要包括α-Al基體相、Al4Si相、單質Si相和Mg2Si強化相等。采用分段加壓的方法顯著減小了變形量,變形率比只采用恒定壓力的變形率減小了 0.3%。在有限元模擬結果的指導下,有針對性的設計和優(yōu)化了焊接方法及工藝參數(shù),從而有效地控制了零件的焊接變形。
[Abstract]:At present, aluminum alloy thin wall complex multilayer structure is widely used in radar antenna and radiator at home and abroad. Aluminum alloy multilayer structure has the characteristics of complex shape, thin channel wall, narrow welding joint, high precision of dimension and position and high difficulty in manufacturing. Therefore, the welding quality is unstable and the product rate is not high in the multilayer structure of aluminum alloy. In this paper, brazing, brazing and diffusion welding are used to connect the multilayer structure of aluminum alloy. The influence of different process parameters on the interface, mechanical properties and deformation of welded joints is analyzed by studying the interface structure of welded joints, and the ANSYS finite element analysis software is used to guide the experiment of controlling welding deformation effectively. Finally, an ideal welding joint was obtained. The multilayer structure of 3A21 aluminum alloy was brazed with Al-Si-Mg filler metal. The best joint was obtained under the condition of brazing temperature 610 鈩，

本文編號：1685514