定向凝固Al-Mn-Be合金初生金属间化合物相生长行为及力学性能
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摘要
对Al-3Mn-7Be合金(原子分数,%)在1~1500 mm/s的抽拉速率下进行定向凝固实验,研究了抽拉速率对合金组织演化、金属间化合物形貌演变和合金力学性能等的影响规律。结果表明,Be元素的加入使二元相图向高Mn区移动,引入了金属间化合物l相、T相、Be4Al Mn和准晶I相,而且Be的加入明显细化了合金的组织。随着抽拉速率的增加,固/液界面过冷度和溶质过饱和度增加,引起初生金属间化合物相的竞争生长,初生相先由λ相转变为T相,后转变为准晶I相,伴随着形成初生Be_4AlMn相。同时,初生相的形貌、尺寸和生长方式也随抽拉速率的增加而发生改变。随着抽拉速率的增加,定向凝固合金的强度先下降后提高,在抽拉速率较低和较高时,定向凝固合金均呈现了较大延伸率,这主要由其定向凝固组织、强化相的种类、形貌以及与基体构成的界面结构决定。
Intermetallic compounds(including quasicrystals) have been widely employed as reinforced phases in many alloys due to their high strength, high hardness and good thermal stability. The growth behavior and growth pattern of these intermetallic compounds affect the mechanical properties of materials significantly. However, the intermetallic compound, which exhibits complex crystal structures and directional bonding usually shows a faceted growth pattern with strong anisotropy and forms crystals with a wide range of morphologies and coarse grains during solidification. The inappropriate morphology and size of the intermetallic compound will destroy the integrity of the matrix and thus deteriorate the me-chanical properties of materials. In this work, the microstructural evolution, morphology evolution of intermetallic compounds and mechanical properties have been investigated in directionally solidified Al-3Mn-7Be(atomic fraction, %) alloy with a wide pulling rates of 1~1500 mm/s. The addition of Be results in the shift of Al-Mn binary phase diagram toward the Mn-rich side, the appearance of intermetallic compounds,namely l-phase, T-phase, Be_4AlMn, and icosahedral quasicrystal(I-phase) and significantly refines the microstructures of the as-cast and directionally solidified samples. With increasing pulling rates, a transition of primary phase is observed from l-phase to T-phase, and then I-phase, accompanied by the formation of the primary Be_4AlMn phase, which can be attributed to the increase of supersaturation and supercooling near the solid/liquid interface. Meanwhile, the morphology, size and growth pattern of primary phases vary with the increase of pulling rates. The mechanical properties of directionally solidified Al-3Mn-7Be alloy have been investigated. It is indicated that the room-temperature strength of this alloy decreases first and then increases as the pulling rates increase, and a larger elongation is presented at the lowest and highest pulling rates, which can be attributed to the microstructures of alloys, properties of strengthening phases and the interfaces between matrix and strengthening phase.
Intermetallic compounds(including quasicrystals) have been widely employed as reinforced phases in many alloys due to their high strength, high hardness and good thermal stability. The growth behavior and growth pattern of these intermetallic compounds affect the mechanical properties of materials significantly. However, the intermetallic compound, which exhibits complex crystal structures and directional bonding usually shows a faceted growth pattern with strong anisotropy and forms crystals with a wide range of morphologies and coarse grains during solidification. The inappropriate morphology and size of the intermetallic compound will destroy the integrity of the matrix and thus deteriorate the me-chanical properties of materials. In this work, the microstructural evolution, morphology evolution of intermetallic compounds and mechanical properties have been investigated in directionally solidified Al-3Mn-7Be(atomic fraction, %) alloy with a wide pulling rates of 1~1500 mm/s. The addition of Be results in the shift of Al-Mn binary phase diagram toward the Mn-rich side, the appearance of intermetallic compounds,namely l-phase, T-phase, Be_4AlMn, and icosahedral quasicrystal(I-phase) and significantly refines the microstructures of the as-cast and directionally solidified samples. With increasing pulling rates, a transition of primary phase is observed from l-phase to T-phase, and then I-phase, accompanied by the formation of the primary Be_4AlMn phase, which can be attributed to the increase of supersaturation and supercooling near the solid/liquid interface. Meanwhile, the morphology, size and growth pattern of primary phases vary with the increase of pulling rates. The mechanical properties of directionally solidified Al-3Mn-7Be alloy have been investigated. It is indicated that the room-temperature strength of this alloy decreases first and then increases as the pulling rates increase, and a larger elongation is presented at the lowest and highest pulling rates, which can be attributed to the microstructures of alloys, properties of strengthening phases and the interfaces between matrix and strengthening phase.
引文
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[19]Kang H J,Wang T M,Lu Y P,et al.Controllable 3D morphology and growth mechanism of quasicrystalline phase in directionally solidified Al-Mn-Be alloy[J].J.Mater.Res.,2014,29:2547
[20]Zupani?F,Bon?ina T,?u?tar?i?B,et al.Microstructure of Al-MnBe melt-spun ribbons[J].Mater.Charact.,2008,59:1245
[21]Jansson?.A thermodynamic evaluation of the Al-Mn system[J].Metall.Trans.,1992,23A:2953
[22]Raynor G V,Faulkner C R,Noden J D,et al.Ternary alloys formed by aluminium,transitional metals and divalent metals[J].Acta Metall.,1953,1:629
[23]Kim S H,Song G S,Fleury E,et al.Icosahedral quasicrystalline and hexagonal approximant phases in the Al-Mn-Be alloy system[J].Philos.Mag.,2002,82A:1495
[24]Kreiner G,Franzen H F.The crystal structure of l-Al4Mn[J].J.Alloys Compd.,1997,261:83
[25]Kelly P M,Ren H P,Qiu D,et al.Identifying close-packed planes in complex crystal structures[J].Acta Mater.,2010,58:3091
[26]Robinson K.The structure of b(Al Mn Si)-Mn3Si Al9[J].Acta Cryst.,1952,5:397
[27]Kurz W,Fisher D J,translated by Li J G,Hu Q D.Fundamentals of Solidification[M].Beijing:Higher Education Press,2010:59(Kurz W,Fisher D J著,李建国,胡侨丹译.凝固原理[M].北京:高等教育出版社,2010:59)
[28]B?gels G,Buijnsters J G,Verhaegen S A C,et al.Morphology and growth mechanism of multiply twinned Ag Br and Ag Cl needle crystals[J].J.Cryst.Growth,1999,203:554
[29]Fleury E,Chang H J,Kim D H.Heterogeneous nucleation of icosahedral phase from FCC phase in cast Al87Mn4Si2Be7alloy[J].Philos.Mag.,2006,86:349
[30]Carrabine J A.Ternary Al Mn Be4phases in commercially pure beryllium[J].J.Nucl.Mater.,1963,8:278
[31]Li C,Wu Y Y,Li H,et al.Morphological evolution and growth mechanism of primary Mg2Si phase in Al-Mg2Si alloys[J].Acta Mater.,2011,59:1058
[32]Hamilton D R,Seidensticker R G.Propagation mechanism of germanium dendrites[J].J.Appl.Phys.,1960,31:1165
[33]Kang H J.Growth behaviour of primary-crystalline phases and mechanical properties of directionally solidified Al-Mn-(Be)alloys[D].Harbin:Harbin Institute of Technology,2013(康慧君.定向凝固Al-Mn-(Be)合金先结晶相生长行为及力学性能[D].哈尔滨:哈尔滨工业大学,2013)
[34]Singh A,Watanabe M,Kato A,et al.Microstructure and strength of quasicrystal containing extruded Mg-Zn-Y alloys for elevated temperature application[J].Mater.Sci.Eng.,2004,A385:382
[35]Lloyd D J.Particle reinforced aluminium and magnesium matrix composites[J].Int.Mater.Rev.,1994,39:1
[36]Kang H J,Wu S P,Li X Z,et al.Improvement of microstructure and mechanical properties of Mg-8Gd-3Y by adding Mg3Zn6Y icosahedral phase alloy[J].Mater.Sci.Eng.2011,A528:5585
[37]Zhang K Y,Bigot J,Chevalier J P,et al.Dodecahedral-shaped quasicrystalline precipitates in dilute Al-Mn solid solutions[J].Philos.Mag.,1988,58B:1
[38]Ohashi T,Dai L,Fukatsu N,et al.Precipitation of quasicrystalline phase in rapidly solidified Al-Mn-Zr alloys[J].Scr.Metall.,1986,20:1241
[39]Loiseau A,Lapasset G.Relations between quasicrystals and crystalline phases in Al-Li-Cu-Mg alloys:A new class of approximant structures[J].Philos.Mag.Lett.,1987,56:165
[2]Hargittai I.Dan Shechtman's quasicrystal discovery in perspective[J].Israel J.Chem.,2011,51:1144
[3]Lubensky T C,Ramaswamy S,Toner J,et al.Dislocation motion in quasicrystals and implications for macroscopic properties[J].Phys.Rev.,1986,33B:7715
[4]Watanabe M,Inoue A,Kimura H M.High mechanical strength of rapidly solidified Al92Mn6Ln2(Ln=lanthanide metal)alloys with finely mixed icosahedral and Al phases[J].Mater.Trans.JIM,1993,34:162
[5]Bae D H,Kim S H,Kim D H,et al.Deformation behavior of MgZn-Y alloys reinforced by icosahedral quasicrystalline particles[J].Acta Mater.,2002,50:2343
[6]Bae D H,Lee M H,Kim K T,et al.Application of quasicrystalline particles as a strengthening phase in Mg-Zn-Y alloys[J].J.Alloys Compd.,2002,342:445
[7]Park E S,Yi S,Ok J B,et al.Solidification and microstructure control of Mg-rich alloys in the Mg-Zn-Y ternary systemya[J].MRS Online Proc.Libr.Arch.,2000,643:K2.5
[8]Singh A,Nakamura M,Watanabe M,et al.Quasicrystal strengthened Mg-Zn-Y alloys by extrusion[J].Scr.Mater.,2003,49:417
[9]Singh A,Osawa Y,Somekawa H,et al.Ultra-fine grain size and isotropic very high strength by direct extrusion of chill-cast Mg-Zn-Y alloys containing quasicrystal phase[J].Scr.Mater.,2011,64:661
[10]Goel D B,Roorkee U P,Furrer P,et al.Precipitation in aluminum manganese(iron,copper)alloys[J].Aluminium,1974,50:511
[11]Huang K,Zhang K,Marthinsen K,et al.Controlling grain structure and texture in Al-Mn from the competition between precipitation and recrystallization[J].Acta Mater.,2017,141:360
[12]Kang H J,Li X Z,Su Y Q,et al.3-D morphology and growth mechanism of primary Al6Mn intermetallic compound in directionally solidified Al-3at.%Mn alloy[J].Intermetallics,2012,23:32
[13]Song G S,Fleury E,Kim S H,et al.Enhancement of the quasicrystal-forming ability in Al-based alloys by Be-addition[J].J.Alloys Compd.,2002,342:251
[14]Chang H J,Fleury E,Song G S,et al.Formation of quasicrystalline phases in Al-rich Al-Mn-Be alloys[J].J.Non-Cryst.Solids,2004,334-335:12
[15]Zupani?F,Bon?ina T,Kri?man A,et al.Quasicrystalline phase in melt-spun Al-Mn-Be ribbons[J].J.Alloys Compd.,2008,452:343
[16]Zupani?F,Markoli B,Nagli?I,et al.Phases in the Al-corner of the Al-Mn-Be System[J].Microsc.Microanal.,2013,19:1308
[17]Liu G H,Zhang Y,Li X Z,et al.Thermal stabilization treatment and the effect on the microstructure in directionally solidified Ti-52%Al alloy[J].Acta Metall.Sin.,2014,50:329(刘国怀,张元,李新中等.定向凝固Ti-52%Al合金热稳定处理及其对微观组织的影响[J].金属学报,2014,50:329)
[18]Luo L S,Liu T,Zhang Y N,et al.Microstructure evolution and growth behoviors of faceted phase in directionally solidified Al-Y alloys I.Microstructure evolution of directionally solidified Al-15%Y hypereutectic alloy[J].Acta Metall.Sin.,2016,52:859(骆良顺,刘桐,张延宁等,定向凝固Al-Y合金组织演化规律及小平面相生长I.Al-15%Y过共晶合金组织演化规律[J].金属学报,2016,52:859)
[19]Kang H J,Wang T M,Lu Y P,et al.Controllable 3D morphology and growth mechanism of quasicrystalline phase in directionally solidified Al-Mn-Be alloy[J].J.Mater.Res.,2014,29:2547
[20]Zupani?F,Bon?ina T,?u?tar?i?B,et al.Microstructure of Al-MnBe melt-spun ribbons[J].Mater.Charact.,2008,59:1245
[21]Jansson?.A thermodynamic evaluation of the Al-Mn system[J].Metall.Trans.,1992,23A:2953
[22]Raynor G V,Faulkner C R,Noden J D,et al.Ternary alloys formed by aluminium,transitional metals and divalent metals[J].Acta Metall.,1953,1:629
[23]Kim S H,Song G S,Fleury E,et al.Icosahedral quasicrystalline and hexagonal approximant phases in the Al-Mn-Be alloy system[J].Philos.Mag.,2002,82A:1495
[24]Kreiner G,Franzen H F.The crystal structure of l-Al4Mn[J].J.Alloys Compd.,1997,261:83
[25]Kelly P M,Ren H P,Qiu D,et al.Identifying close-packed planes in complex crystal structures[J].Acta Mater.,2010,58:3091
[26]Robinson K.The structure of b(Al Mn Si)-Mn3Si Al9[J].Acta Cryst.,1952,5:397
[27]Kurz W,Fisher D J,translated by Li J G,Hu Q D.Fundamentals of Solidification[M].Beijing:Higher Education Press,2010:59(Kurz W,Fisher D J著,李建国,胡侨丹译.凝固原理[M].北京:高等教育出版社,2010:59)
[28]B?gels G,Buijnsters J G,Verhaegen S A C,et al.Morphology and growth mechanism of multiply twinned Ag Br and Ag Cl needle crystals[J].J.Cryst.Growth,1999,203:554
[29]Fleury E,Chang H J,Kim D H.Heterogeneous nucleation of icosahedral phase from FCC phase in cast Al87Mn4Si2Be7alloy[J].Philos.Mag.,2006,86:349
[30]Carrabine J A.Ternary Al Mn Be4phases in commercially pure beryllium[J].J.Nucl.Mater.,1963,8:278
[31]Li C,Wu Y Y,Li H,et al.Morphological evolution and growth mechanism of primary Mg2Si phase in Al-Mg2Si alloys[J].Acta Mater.,2011,59:1058
[32]Hamilton D R,Seidensticker R G.Propagation mechanism of germanium dendrites[J].J.Appl.Phys.,1960,31:1165
[33]Kang H J.Growth behaviour of primary-crystalline phases and mechanical properties of directionally solidified Al-Mn-(Be)alloys[D].Harbin:Harbin Institute of Technology,2013(康慧君.定向凝固Al-Mn-(Be)合金先结晶相生长行为及力学性能[D].哈尔滨:哈尔滨工业大学,2013)
[34]Singh A,Watanabe M,Kato A,et al.Microstructure and strength of quasicrystal containing extruded Mg-Zn-Y alloys for elevated temperature application[J].Mater.Sci.Eng.,2004,A385:382
[35]Lloyd D J.Particle reinforced aluminium and magnesium matrix composites[J].Int.Mater.Rev.,1994,39:1
[36]Kang H J,Wu S P,Li X Z,et al.Improvement of microstructure and mechanical properties of Mg-8Gd-3Y by adding Mg3Zn6Y icosahedral phase alloy[J].Mater.Sci.Eng.2011,A528:5585
[37]Zhang K Y,Bigot J,Chevalier J P,et al.Dodecahedral-shaped quasicrystalline precipitates in dilute Al-Mn solid solutions[J].Philos.Mag.,1988,58B:1
[38]Ohashi T,Dai L,Fukatsu N,et al.Precipitation of quasicrystalline phase in rapidly solidified Al-Mn-Zr alloys[J].Scr.Metall.,1986,20:1241
[39]Loiseau A,Lapasset G.Relations between quasicrystals and crystalline phases in Al-Li-Cu-Mg alloys:A new class of approximant structures[J].Philos.Mag.Lett.,1987,56:165