Si_p/LD11复合材料激光钎焊特性与Si的结晶行为
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摘要
硅颗粒增强的铝基复合材料是一种新型的复合材料,具有轻质、低膨胀、高导热、环保利于回收等优点,在航空、航天、电子封装等领域具有广阔的应用前景。这种材料一般硅颗粒所占比分较高,一旦熔化,熔池含硅量很高,凝固后往往存在大量的缩孔,组织为十分粗大的板条状硅。大大恶化了性能,失去了应用价值。
本文利用激光填丝钎焊工艺,含硅量为12%的4047铝硅药芯焊丝作为填充材料,对硅颗粒增强铝基复合材料的焊接特性进行了系统的研究。首先确立了对激光钎焊工艺尤为重要的光斑类型、坡口形式两个工艺条件,从表面成型和组织形态均匀性两方面考虑,试验研究了各工艺参数对成形和组织的影响,获得了优化的工艺参数,得到了表面平滑稳定、焊缝中含有大量增强相的接头。
焊缝的组成元素只有铝和硅,而铝硅之间没有直接的冶金反应,组织组成即为简单的初晶硅和共晶组织。因此焊接过程中硅的溶解扩散对其结晶行为和组织结构影响重大。本文在分析硅的溶解、扩散、结晶行为的基础上,研究了不同工艺条件下焊缝不同部位硅元素的分布、存在形式与结构特征。结果发现,焊缝中的硅主要有两种存在形态,即初晶硅和共晶硅。初晶硅为颗粒状,弥散的分布在焊缝中,共晶硅在不同的位置表现出不同的形貌,界面处为细长的针状树枝晶,在焊缝中心呈现细小的短棒状。研究后发现,这种短棒状的共晶硅是以共晶团的方式长大的。
最后,为改善初晶硅的尖角和针状共晶硅的形貌,避免其尖角割裂基体并使得焊缝组织均匀,获得热膨胀系数等物理性能的各向同性。提出进行热处理,结果发现在合适的热处理工艺下(T=550°C、t=8h、随炉冷却)针状的还有短棒状的共晶硅都破碎聚集成颗粒状,初生硅的尖角也得到了钝化,焊缝组织变得均匀。
Silicon particles reinforced aluminum matrix composites is a new type of composite materials. With advantages of light weight, low expansion, high thermal conductivity, environmental protection and good recyclability, it has broad application prospects in the aviation, the spaceflight, the electronic packing and other fields. However, as it has a large proportion of silicon particles in this kind of materials, which leads to a high content of silicon in the molten pool once melted, there remain a lot of shrinkages and very coarse lath-shaped Si in the material after the solidification, deteriorating the performances of the material significantly and losing the application values.
In this paper, the welding characteristics of silicon particle reinforced aluminum matrix composites were investigated systematically, using the laser brazing filler wire technology, with the 4047 Al-Si (12% silicon content) flux cored wire as a filling material. First, the types of the laser spot and the groove, both of which are particularly important to the laser soldering process, were established. The effects of various processing parameters on the forming and organizations were studied through experiments, considering in the perspective of the surface forming and the uniformity of structure morphology. Optimized parameters, and the stable joints with smoothing surfaces and a high content of reinforcements in the weld, were obtained.
The dissolution and diffusion of silicon during the welding has significant impact on its crystallization behavior and the structure of the material. The distributions, existing forms and structure characteristics of Si in different areas of the welds under various processing conditions were studied in this paper, based on the analysis of the dissolution, diffusion and crystallization behaviors of Si. The results show that the silicon exists mainly in two forms, namely, primary silicon and eutectic silicon, in the welds. Granular primary silicon dispersively distributes in the weld. The eutectic silicon in different locations shows different morphologies, for instance, the slender needle-like dendrites in the interfaces and the small short rods in the weld center. Studies find that the short rods of the eutectic silicon grow up in the way of eutectic clusters.
Finally, the heat treatment (550°C, holding for 8h, with furnace cooling) were carried out, to improve the primary silicon’s sharp corner and the morphology of the needle eutectic silicon to prevent them from splitting the matrix and deteriorating performances. The results show that both the needle and short rod eutectic silicon have broken and assembled into granules, and the sharp-cornered primary silicon has also been passivated, making the structure of the weld uniform.
本文利用激光填丝钎焊工艺,含硅量为12%的4047铝硅药芯焊丝作为填充材料,对硅颗粒增强铝基复合材料的焊接特性进行了系统的研究。首先确立了对激光钎焊工艺尤为重要的光斑类型、坡口形式两个工艺条件,从表面成型和组织形态均匀性两方面考虑,试验研究了各工艺参数对成形和组织的影响,获得了优化的工艺参数,得到了表面平滑稳定、焊缝中含有大量增强相的接头。
焊缝的组成元素只有铝和硅,而铝硅之间没有直接的冶金反应,组织组成即为简单的初晶硅和共晶组织。因此焊接过程中硅的溶解扩散对其结晶行为和组织结构影响重大。本文在分析硅的溶解、扩散、结晶行为的基础上,研究了不同工艺条件下焊缝不同部位硅元素的分布、存在形式与结构特征。结果发现,焊缝中的硅主要有两种存在形态,即初晶硅和共晶硅。初晶硅为颗粒状,弥散的分布在焊缝中,共晶硅在不同的位置表现出不同的形貌,界面处为细长的针状树枝晶,在焊缝中心呈现细小的短棒状。研究后发现,这种短棒状的共晶硅是以共晶团的方式长大的。
最后,为改善初晶硅的尖角和针状共晶硅的形貌,避免其尖角割裂基体并使得焊缝组织均匀,获得热膨胀系数等物理性能的各向同性。提出进行热处理,结果发现在合适的热处理工艺下(T=550°C、t=8h、随炉冷却)针状的还有短棒状的共晶硅都破碎聚集成颗粒状,初生硅的尖角也得到了钝化,焊缝组织变得均匀。
Silicon particles reinforced aluminum matrix composites is a new type of composite materials. With advantages of light weight, low expansion, high thermal conductivity, environmental protection and good recyclability, it has broad application prospects in the aviation, the spaceflight, the electronic packing and other fields. However, as it has a large proportion of silicon particles in this kind of materials, which leads to a high content of silicon in the molten pool once melted, there remain a lot of shrinkages and very coarse lath-shaped Si in the material after the solidification, deteriorating the performances of the material significantly and losing the application values.
In this paper, the welding characteristics of silicon particle reinforced aluminum matrix composites were investigated systematically, using the laser brazing filler wire technology, with the 4047 Al-Si (12% silicon content) flux cored wire as a filling material. First, the types of the laser spot and the groove, both of which are particularly important to the laser soldering process, were established. The effects of various processing parameters on the forming and organizations were studied through experiments, considering in the perspective of the surface forming and the uniformity of structure morphology. Optimized parameters, and the stable joints with smoothing surfaces and a high content of reinforcements in the weld, were obtained.
The dissolution and diffusion of silicon during the welding has significant impact on its crystallization behavior and the structure of the material. The distributions, existing forms and structure characteristics of Si in different areas of the welds under various processing conditions were studied in this paper, based on the analysis of the dissolution, diffusion and crystallization behaviors of Si. The results show that the silicon exists mainly in two forms, namely, primary silicon and eutectic silicon, in the welds. Granular primary silicon dispersively distributes in the weld. The eutectic silicon in different locations shows different morphologies, for instance, the slender needle-like dendrites in the interfaces and the small short rods in the weld center. Studies find that the short rods of the eutectic silicon grow up in the way of eutectic clusters.
Finally, the heat treatment (550°C, holding for 8h, with furnace cooling) were carried out, to improve the primary silicon’s sharp corner and the morphology of the needle eutectic silicon to prevent them from splitting the matrix and deteriorating performances. The results show that both the needle and short rod eutectic silicon have broken and assembled into granules, and the sharp-cornered primary silicon has also been passivated, making the structure of the weld uniform.
引文
1陈绍杰.复合材料技术与大型飞机.航空学报. 2008, 29(13):605-610
2李琦,龚烈航.复合材料在工程机械中的应用研究.矿山机械. 2004,(11):38-39
3吕一中,崔岩,曲敬信.金属基复合材料在航空航天领域的应用.北京工业职业技术学院学报. 2007,6(3):1-4
4胥锴,刘政,刘萍.金属基复合材料的发展及其应用.南方金属. 2005,147:1-6
5 S. Das. Development of Aluminum Alloy Composites for Engineering Applications. Trans.Indian Inst.Met. 2004, 8(4):325-334
6 M. Jacobson, S. P. S. Sangha. Future trends in materials for lightweight microwave packaging. Microeletronics Int. 1998, (3):47
7 S. S. Sangha, Novel Aluminum Silicon Alloys for Electronics packaging. Journal of Engineening Science and Education. 1997, (11):195
8杨会娟,王志法,王海山等.电子封装材料的研究现状及进展.材料导报2004,6(8):86-88
9武高辉,修子杨.环保型电子封装用Sip/Al复合材料性能研究,材料科学与工艺. 2006,14(3):244-250
10 S. C. Lim, M. Gupta. Wear of spray-deposited hypereutectic aluminum-silicon alloy. Material processing technology. 1997,63:865-870
11 M. K. Surappa, Aluminum matrix composites: Challenges and opportunities . Sadhana. 2003, (28):319–334
12 A. Urena, J. M. Gomez de Salazar, M. D. Escalera. Influence of metal-ceramic interfaces on the behavior of metal matrix composites and their joints. Key Engineering Materials. 1997,(127-131):687-694
13 A. Urena, M. D. Escalera, L. Gil. Influence of interface reactions on fracture mechanisms in TIG. arc-welded aluminum matrix composites. Composites Science and Technology. 2000,60:613–622
14陈彦宾,张德库,牛济泰.激光焊接铝基复合材料钛的原位增强作用.应用激光. 2002,2(3):320-322
15冀国娟,谢建国,薛文涛. SiC/101铝基复合材料的填加焊丝TIG焊.有色金属. 2003,55(4):21-23
16刘金合,王辉. SiC颗粒增强铝基复合材料的真空电子束焊接.核技术. 2006,22(2):133-135
17刘黎明,高振坤. SiCw/ 6061Al铝基复合材料粉末夹层瞬间液相扩散焊接工艺.中国有色金属学报. 2005, 15(6):849-853
18 Zhiwu Xu, Jiuchun Yan, Baoyou Zhang, Behaviors of oxide ?lm at the ultrasonic aided interaction interface of Zn–Al alloy and Al2O3p/6061Al composites in air. Materials Science and Engineering. 2006: 80–86
19 Hiroshi Morimoto, Takashi Tanaka, Tohru Saito. Effects of brazing temperature on joint properties of SiC fiber reinforced aluminum alloy matrix composites. Adnances in Joining Newer Structure Materials. 1990:137-142
20 Hüseyin Uzun, Friction stir welding of SiC particulate reinforced AA2124 aluminium alloy matrix composite. Materials and Design. 2007,28(5):1440-1446
21 L. Ceschinia, I. Boromei, G. Minak. E?ect of friction stir welding on microstructure, tensile and fatigue properties of the Al2O3p/Al6061 composite. Composites Science and Technology. 2007, 67:605-615
22 J. Husner, A. Luft, C. Olaineck. Laser Brazing in Automobile Production. Thyssen Krupp Techforum. 2003:58-63
23 Alexandre Mathieu, Sebastien Pontevicci, Jean-claude Viala. Laser brazing of a steel/aluminum assembly with hot ?ller wire (88% Al, 12% Si). Materials Science and Engineering. 2006:19-28
24 T. Markovits, J. Takacs, A. Lovas. Laser Brazing of Aluminum. Journal of Materials Processing Technology. 2003, (1):651-655
25 Laukant, C. Wallmann, M-Korte. Flux-less Joining Technique of Aluminum with Zinc-coated Steel Sheets by a Dual-spot-laser Beam. Sheet Metal 2005. Proceedings of the 11th International Conference on Sheet Metal. 2005:163-170
26 Li M G, Sun D Q, Qiu X M. Effect of Ti on Melting Temperature and Microstructure of Ag-Cu-Zn-Sn Filler Metals. Materials Science and Technology. 2005,21 (11):1318-1322
27 Xu C L, Wang H Y, Liu C. Growth of octahedral primary silicon in cast hypereutectic alloy. J Crystal Growth. 2006,291(2):540
28齐广慧,刘相法,杨志强.“绿色”高效Al-Si合金变质剂.材料科学与工艺. 2001,9(2):211
29刘相法,乔进国,刘玉先. Al-P中间合金对共晶和过共晶Al-Si合金的变质机制.金属学报. 2004,40(5):471
30 Zeng Da-xin, SU Jun-yi. Dissolution and Melting of Solid Metals in Liquid Metals.
31陆文华,李隆盛,黄良余.铸造合金及其熔炼.机械工业出版社. 2002:262
32 Y. T. Pei, TH. M. De Hosson. Functionally graded materials produced by laser cladding. Acta mater. 2000, (48):2617–2624
33葛良琦. Al-20%Si中初生硅形态控制技术研究.南京理工大学硕士学位论文. 2007,7
34 U. Dahlborg, M. Bessr. Structure of molten Al–Si alloys. Non-Crystalline Solids. 2007,353:3005-3010.
35 Zhang Jin shan, Xu Chun xiang, Han Fu gen. Effect of composite modifier on structures and properties of hypereutectic Al-Si alloy. The Chinese Journal of Nonferrous Metals. 2002,12:107-109.
36 Xu Zhenhu. A study on solidified structures of Al-Si alloys under rotary magnetic field condition. Foundry. 2000,49(2):115-119
37 K. Sangwal. Growth kinetics and surface morphology of crystals growth from solutions recent observations and their interpretations. Progress in Crystal Growth and Characterization. 1998,36(3):163-248.
38 R. E. Napolitano, H. Meco, C. Jung. Faceted solidification morphologies in low-growth–rate Al-Si eutectics. 2004,56:16-21.
39桂满昌.贾均.李庆春,五瓣星状初晶硅形核机制.金属学报. 1996,32(11):11
40 Kobayashi K F, Hogan L M. J Material Science, 1985:20
41徐长林.变质对过共晶铝硅合金中初生硅的影响极其作用机制.吉林大学博士学位论文. 2007.7:14-16
42张蓉,沈淑娟,赵志龙等.熔体过热处理及冷却速度对Al-Si过共晶合金凝固组织的影响.有色金属. 2002,54(3):19
43吴振平,廖恒成,姜云峰等. Sr对Al-15.5Si合金共晶团大小的影响.特种铸造及有色合金. 2005,(4):193-195
44刘顺华,郭可仞. Na对共晶型Al-Si合金共晶团的影响.大连工学院学报. 1984,23(4):17-21
45张蓉,黄太文,刘林.过共晶Al-Si合金熔体中初生硅生长特性.中国有色金属学报. 2004,14(2):262-266
46张忠华,张景祥,边秀房.新型高效PM磷变质剂.特种铸造及有色合金,. 2000,2:13-15
47修子扬.三维网络结构Si3d/Al复合材料微观组织设计及性能研究.哈尔滨工业大学博士学位论文. 2008,2:65-87
48王小锋,武高辉,修子扬. Sip/Al复合材料中的界面和硅相形貌的演变.中国有色金属学报. 2009,19(3):479-483
2李琦,龚烈航.复合材料在工程机械中的应用研究.矿山机械. 2004,(11):38-39
3吕一中,崔岩,曲敬信.金属基复合材料在航空航天领域的应用.北京工业职业技术学院学报. 2007,6(3):1-4
4胥锴,刘政,刘萍.金属基复合材料的发展及其应用.南方金属. 2005,147:1-6
5 S. Das. Development of Aluminum Alloy Composites for Engineering Applications. Trans.Indian Inst.Met. 2004, 8(4):325-334
6 M. Jacobson, S. P. S. Sangha. Future trends in materials for lightweight microwave packaging. Microeletronics Int. 1998, (3):47
7 S. S. Sangha, Novel Aluminum Silicon Alloys for Electronics packaging. Journal of Engineening Science and Education. 1997, (11):195
8杨会娟,王志法,王海山等.电子封装材料的研究现状及进展.材料导报2004,6(8):86-88
9武高辉,修子杨.环保型电子封装用Sip/Al复合材料性能研究,材料科学与工艺. 2006,14(3):244-250
10 S. C. Lim, M. Gupta. Wear of spray-deposited hypereutectic aluminum-silicon alloy. Material processing technology. 1997,63:865-870
11 M. K. Surappa, Aluminum matrix composites: Challenges and opportunities . Sadhana. 2003, (28):319–334
12 A. Urena, J. M. Gomez de Salazar, M. D. Escalera. Influence of metal-ceramic interfaces on the behavior of metal matrix composites and their joints. Key Engineering Materials. 1997,(127-131):687-694
13 A. Urena, M. D. Escalera, L. Gil. Influence of interface reactions on fracture mechanisms in TIG. arc-welded aluminum matrix composites. Composites Science and Technology. 2000,60:613–622
14陈彦宾,张德库,牛济泰.激光焊接铝基复合材料钛的原位增强作用.应用激光. 2002,2(3):320-322
15冀国娟,谢建国,薛文涛. SiC/101铝基复合材料的填加焊丝TIG焊.有色金属. 2003,55(4):21-23
16刘金合,王辉. SiC颗粒增强铝基复合材料的真空电子束焊接.核技术. 2006,22(2):133-135
17刘黎明,高振坤. SiCw/ 6061Al铝基复合材料粉末夹层瞬间液相扩散焊接工艺.中国有色金属学报. 2005, 15(6):849-853
18 Zhiwu Xu, Jiuchun Yan, Baoyou Zhang, Behaviors of oxide ?lm at the ultrasonic aided interaction interface of Zn–Al alloy and Al2O3p/6061Al composites in air. Materials Science and Engineering. 2006: 80–86
19 Hiroshi Morimoto, Takashi Tanaka, Tohru Saito. Effects of brazing temperature on joint properties of SiC fiber reinforced aluminum alloy matrix composites. Adnances in Joining Newer Structure Materials. 1990:137-142
20 Hüseyin Uzun, Friction stir welding of SiC particulate reinforced AA2124 aluminium alloy matrix composite. Materials and Design. 2007,28(5):1440-1446
21 L. Ceschinia, I. Boromei, G. Minak. E?ect of friction stir welding on microstructure, tensile and fatigue properties of the Al2O3p/Al6061 composite. Composites Science and Technology. 2007, 67:605-615
22 J. Husner, A. Luft, C. Olaineck. Laser Brazing in Automobile Production. Thyssen Krupp Techforum. 2003:58-63
23 Alexandre Mathieu, Sebastien Pontevicci, Jean-claude Viala. Laser brazing of a steel/aluminum assembly with hot ?ller wire (88% Al, 12% Si). Materials Science and Engineering. 2006:19-28
24 T. Markovits, J. Takacs, A. Lovas. Laser Brazing of Aluminum. Journal of Materials Processing Technology. 2003, (1):651-655
25 Laukant, C. Wallmann, M-Korte. Flux-less Joining Technique of Aluminum with Zinc-coated Steel Sheets by a Dual-spot-laser Beam. Sheet Metal 2005. Proceedings of the 11th International Conference on Sheet Metal. 2005:163-170
26 Li M G, Sun D Q, Qiu X M. Effect of Ti on Melting Temperature and Microstructure of Ag-Cu-Zn-Sn Filler Metals. Materials Science and Technology. 2005,21 (11):1318-1322
27 Xu C L, Wang H Y, Liu C. Growth of octahedral primary silicon in cast hypereutectic alloy. J Crystal Growth. 2006,291(2):540
28齐广慧,刘相法,杨志强.“绿色”高效Al-Si合金变质剂.材料科学与工艺. 2001,9(2):211
29刘相法,乔进国,刘玉先. Al-P中间合金对共晶和过共晶Al-Si合金的变质机制.金属学报. 2004,40(5):471
30 Zeng Da-xin, SU Jun-yi. Dissolution and Melting of Solid Metals in Liquid Metals.
31陆文华,李隆盛,黄良余.铸造合金及其熔炼.机械工业出版社. 2002:262
32 Y. T. Pei, TH. M. De Hosson. Functionally graded materials produced by laser cladding. Acta mater. 2000, (48):2617–2624
33葛良琦. Al-20%Si中初生硅形态控制技术研究.南京理工大学硕士学位论文. 2007,7
34 U. Dahlborg, M. Bessr. Structure of molten Al–Si alloys. Non-Crystalline Solids. 2007,353:3005-3010.
35 Zhang Jin shan, Xu Chun xiang, Han Fu gen. Effect of composite modifier on structures and properties of hypereutectic Al-Si alloy. The Chinese Journal of Nonferrous Metals. 2002,12:107-109.
36 Xu Zhenhu. A study on solidified structures of Al-Si alloys under rotary magnetic field condition. Foundry. 2000,49(2):115-119
37 K. Sangwal. Growth kinetics and surface morphology of crystals growth from solutions recent observations and their interpretations. Progress in Crystal Growth and Characterization. 1998,36(3):163-248.
38 R. E. Napolitano, H. Meco, C. Jung. Faceted solidification morphologies in low-growth–rate Al-Si eutectics. 2004,56:16-21.
39桂满昌.贾均.李庆春,五瓣星状初晶硅形核机制.金属学报. 1996,32(11):11
40 Kobayashi K F, Hogan L M. J Material Science, 1985:20
41徐长林.变质对过共晶铝硅合金中初生硅的影响极其作用机制.吉林大学博士学位论文. 2007.7:14-16
42张蓉,沈淑娟,赵志龙等.熔体过热处理及冷却速度对Al-Si过共晶合金凝固组织的影响.有色金属. 2002,54(3):19
43吴振平,廖恒成,姜云峰等. Sr对Al-15.5Si合金共晶团大小的影响.特种铸造及有色合金. 2005,(4):193-195
44刘顺华,郭可仞. Na对共晶型Al-Si合金共晶团的影响.大连工学院学报. 1984,23(4):17-21
45张蓉,黄太文,刘林.过共晶Al-Si合金熔体中初生硅生长特性.中国有色金属学报. 2004,14(2):262-266
46张忠华,张景祥,边秀房.新型高效PM磷变质剂.特种铸造及有色合金,. 2000,2:13-15
47修子扬.三维网络结构Si3d/Al复合材料微观组织设计及性能研究.哈尔滨工业大学博士学位论文. 2008,2:65-87
48王小锋,武高辉,修子扬. Sip/Al复合材料中的界面和硅相形貌的演变.中国有色金属学报. 2009,19(3):479-483