一种新型高锌Al-Zn-Mg-Cu合金的热处理工艺
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摘要
采用热顶直冷半连续铸造法制备了一种Zn元素含量达9.6%(质量分数)的Al-Zn-Mg-Cu系铝合金。利用金相显微镜、透射电镜进行微观组织观察,采用差热分析仪测试相转变温度。测试了硬度、拉伸性能并利用扫描电镜进行断口分析。表明:铸锭的铸态组织细小,晶间共晶相较少,共晶相的熔化温度为473.4℃。铸锭的均匀化工艺为465℃/24h,经均匀化处理后,晶界变为断续状,晶界相明显回溶。通过挤压法制备合金棒材,系统研究挤压棒材在不同温度下的单级和三级时效硬化曲线。表明在135℃/12h的单级时效制度下,合金挤压棒材的峰值硬度为197.7HBS,抗拉强度、屈服强度和伸长率分别为727.5,718.0MPa和9.3%;在120℃/24h+190℃/5min+135℃/3h的三级时效制度下,合金挤压棒材的峰值硬度为204.7HBS,抗拉强度、屈服强度和伸长率分别为764.0,749.0MPa和7.2%。
A kind of Al-Zn-Mg-Cu alloy containing 9.6%(mass fraction)Zn element was produced by the Hot-top semi-continuous DC casting technology.The microstructure of the alloy and the temperature of phases transformation were investigated by optical microscopy(OM),transmission electron microscopy(TEM)and differential scanning calorimetry(DSC)respectively.The hardness and tensile properties of the alloy were tested,and the fracture was studied by scanning electron microscopy(SEM).Results show that the as-cast microstructure of this alloy is fine and has less intergranular eutectic phases,with the melting temperature of 473.4℃.Therefore,the homogenization heat-treatment is 465℃/24 h.After the homogenization heat-treatment,the grain boundary of the ingot has turned to be intermittent and the phases have dissolved significantly.Besides,the systematic experiments were conducted on the T6 and RRA of this alloy after extrusion.The results show that on the condition of 135℃/12 htreatment,the highest hardness is 197.7HBS,and the tensile strength,yield strength,elongation are 727.5,718.0MPa and 9.3% respectively.On the condition of 120℃/24h+190℃/5min+135℃/3htreatment,the highest hardness is 204.7HBS,and the tensile strength,yield strength,elongation can reach 764.0,749.0MPa and 7.2%respectively.
A kind of Al-Zn-Mg-Cu alloy containing 9.6%(mass fraction)Zn element was produced by the Hot-top semi-continuous DC casting technology.The microstructure of the alloy and the temperature of phases transformation were investigated by optical microscopy(OM),transmission electron microscopy(TEM)and differential scanning calorimetry(DSC)respectively.The hardness and tensile properties of the alloy were tested,and the fracture was studied by scanning electron microscopy(SEM).Results show that the as-cast microstructure of this alloy is fine and has less intergranular eutectic phases,with the melting temperature of 473.4℃.Therefore,the homogenization heat-treatment is 465℃/24 h.After the homogenization heat-treatment,the grain boundary of the ingot has turned to be intermittent and the phases have dissolved significantly.Besides,the systematic experiments were conducted on the T6 and RRA of this alloy after extrusion.The results show that on the condition of 135℃/12 htreatment,the highest hardness is 197.7HBS,and the tensile strength,yield strength,elongation are 727.5,718.0MPa and 9.3% respectively.On the condition of 120℃/24h+190℃/5min+135℃/3htreatment,the highest hardness is 204.7HBS,and the tensile strength,yield strength,elongation can reach 764.0,749.0MPa and 7.2%respectively.
引文
[1]NAKAI M,ETO T.New aspects of development of high strength aluminum alloy for aerospace applications[J].Mater Sci Eng:A,2000,285(10):62-68.
[2]赵晓东,韩连华,陈慧琴,等.时效预处理态Al-Zn-Mg-Cu合金热变形及其后热处理过程中的晶粒组织的演变[J].稀有金属材料与工程,2015,44(4):982-988.ZHAO X D,HAN L H,CHEN H Q,et al.Grain evolution during hot deformation and subsequent heat treatment processes of as-aging pre-treated Al-Zn-Mg-Cu alloy[J].Rare Metal Materials and Engineering,2015,44(4):982-988.
[3]夏涛,陈子勇,聂祚仁.高锌超高强铝合金微观组织及力学性能研究[J].热加工工艺,2015,44(2):50-53.XIA T,CHEN Z Y,NIE Z R.Microstructure and mechanical properties of ultra-high strength aluminum alloy with high zinc content[J].Hot Working Technology,2015,44(2):50-53.
[4]曾渝,尹志民,潘青林.超高强铝合金的研究现状及发展[J].中南工业大学学报,2002,33(6):592-595.ZENG Y,YIN Z M,PAN Q L.Present research and developing of ultra high strength aluminium alloys[J].Journal of Central South University of Technology,2002,33(6):592-595.
[5]戴晓元,夏长青,孙振起.Al-9.0Zn-2.5Mg-1.2Cu-0.12Sc-0.15Zr合金的组织和性能[J].中国有色金属学报,2007,17(3):396-401.DAI X Y,XIA C Q,SUN Z Q.Microstructure and properties of Al-9.0Zn-2.5Mg-1.2Cu-0.12Sc-0.15Zr alloy[J].The Chinese Journal of Nonferrous Metals,2007,17(3):396-401.
[6]STARKE E A,STALEY J T.Application of modern aluminum alloys to aircraft[J].Progress in Aerospace Sciences,1996,32:131-172.
[7]潘复生,张丁非.铝合金及应用[M].北京:化学工业出版社,2006.PAN F S,ZHANG D F.Aluminum Alloy and Its Application[M].Beijing:Chemical Industry Press,2006.
[8]CONG F G,ZHAO G,JIANG F,et al.Effect of homogenization treatment on microstructure and mechanical properties of DC cast7X50aluminum alloy[J].Transactions of Nonferrous Metals Society of China,2015,25:1027-1034.
[9]黄元春,刘宇,肖政兵,等.时效处理对Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr合金超声铸锭轧件组织与抗腐蚀性能的影响[J].粉末冶金材料科学与工程,2015,20(2):280-287.HUANG Y C,LIU Y,XIAO Z B,et al.Effect of aging treatment on microstructure and corrosion properties of plate rolling with ultrasonic casting Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr aluminum alloy ingot[J].Materials Science and Engineering of Powder Metallurgy,2015,20(2):280-287.
[10]舒文祥,侯陇刚,刘君城,等.先进高强韧Al-Zn-Mg-Cu合金凝固和均匀化组织及相构成[J].北京科技大学学报,2014,36(11):1534-1539.SHU W X,HOU L G,LIU J C,et al.Microstructure and phase components of as-cast and homogenized advanced Al-Zn-Mg-Cu alloys with high strength and toughness[J].Journal of University of Science and Technology Beijing,2014,36(11):1534-1539.
[11]张新明,吴泽政,刘胜胆,等.固溶处理对7A55铝合金局部腐蚀性能的影响[J].材料工程,2014,(4):26-33.ZHANG X M,WU Z Z,LIU S D,et al.Influence of solution heat treatment on localized corrosion of 7A55aluminum alloy[J].Journal of Materials Engineering,2014,(4):26-33.
[12]滕海涛,熊柏青,张永安,等.高Zn含量Al-Zn-Mg-Cu系铝合金的凝固态显微组织[J].中国有色金属学报,2015,25(4):852-865.TENG H T,XIONG B Q,ZHANG Y A,et al.Solidification microstructure of high zinc-containing Al-Zn-Mg-Cu alloys[J].The Chinese Journal of Nonferrous Metals,2015,25(4):852-865.
[13]LI Y X,LI P,ZHAO G.The constituents in Al-10Zn-2.5Mg-2.5Cu aluminum alloy[J].Mater Sci and Eng:A,2005,397(1-2):204-208.
[14]MONDAL C,MUKHOPADHYAY A K.On the nature of T(Al2Mg3Zn3)and S(Al2CuMg)phases present in as-cast and annealed 7055aluminum alloy[J].Materials Science and Engineering:A,2005,391(1-2):367-376.
[15]李国爱.700MPa级超高强铝合金锻件成分设计及制备工艺研究[D].北京:北京航空材料研究院,2012.LI G A.Research on the composition design and preparation technology of 700MPa ultra-high strength aluminum alloy[D].Beijing:Beijing Institute of Aeronautical Materials,2012.
[16]宁爱林.析出相及其分布对高强铝合金力学性能的影响[D].长沙:中南大学,2007.NING A L.The effect of precipitation and its distribution to high strength aluminum alloy[D].Changsha:Central South University,2007.
[17]KNIGHT S P,BIRBILIS N,MUDDLE B C,et al.Correlations between intergranular stress corrosion cracking,grain-boundary microchemistry,and grain-boundary electrochemistry for Al-ZnMg-Cu alloys[J].Corrosion Science,2010,52(12):4073-4080.
[18]王祝堂,田荣璋.铝合金及其加工手册[M].长沙:中南大学出版社,2005.WANG Z T,TIAN R Z.Aluminum Alloy and Its Processing Manual[M].Changsha:Central South University Press,2005.
[19]PAUL A,ZHANG Y.Heat treatment of 7xxx series aluminum alloys-some recent developments[J].Transactions of Nonferrous Metals Society of China,2014,24:2003-2017.
[20]GROSVENOR A.Microstructural evolution during retrogression and reaging treatment of aluminum alloy 7075[D].Melbourne:Monash University,2008.
[21]AMS 2772E.Heat Treatment of Aluminum Alloy Raw Materials[M].Warrendale,USA:International,2008.16-20.
[22]KNIGHT S P.Stress corrosion cracking of Al-Zn-Mg-Cu alloys:effects of heat-treatment,environment,and alloy composition[D].Melbourne:Monash University,2008.
[23]KNIGHT S P,BIRBILIS N,MUDDLE B C,et al.Correlations between intergranular stress corrosion cracking,grain-boundary microchemistry,and grain-boundary electrochemistry for Al-ZnMg-Cu alloys[J].Corrosion Science,2010,52:4073-4080.
[24]HUANG L P,CHEN K H,LI S.Influence of grain-boundary pre-precipitation and corrosion characteristics of inter-granular phases on corrosion behaviors of an Al-Zn-Mg-Cu alloy[J].Materials Science and Engineering:B,2012,177:862-868.
[25]De GEUSER F,DESCHAMPS A.Precipitate characterization in metallic systems by small-angle X-ray or neutron scattering[J].Comptes Rendus Physique,2012,13:246-256.
[26]DESCHAMPS A,de GEUSER F.Quantitative characterization of precipitate microstructures in metallic alloys using small-angles scattering[J].Metallurgical and Materials Transactions A,2013,44:77-86.
[2]赵晓东,韩连华,陈慧琴,等.时效预处理态Al-Zn-Mg-Cu合金热变形及其后热处理过程中的晶粒组织的演变[J].稀有金属材料与工程,2015,44(4):982-988.ZHAO X D,HAN L H,CHEN H Q,et al.Grain evolution during hot deformation and subsequent heat treatment processes of as-aging pre-treated Al-Zn-Mg-Cu alloy[J].Rare Metal Materials and Engineering,2015,44(4):982-988.
[3]夏涛,陈子勇,聂祚仁.高锌超高强铝合金微观组织及力学性能研究[J].热加工工艺,2015,44(2):50-53.XIA T,CHEN Z Y,NIE Z R.Microstructure and mechanical properties of ultra-high strength aluminum alloy with high zinc content[J].Hot Working Technology,2015,44(2):50-53.
[4]曾渝,尹志民,潘青林.超高强铝合金的研究现状及发展[J].中南工业大学学报,2002,33(6):592-595.ZENG Y,YIN Z M,PAN Q L.Present research and developing of ultra high strength aluminium alloys[J].Journal of Central South University of Technology,2002,33(6):592-595.
[5]戴晓元,夏长青,孙振起.Al-9.0Zn-2.5Mg-1.2Cu-0.12Sc-0.15Zr合金的组织和性能[J].中国有色金属学报,2007,17(3):396-401.DAI X Y,XIA C Q,SUN Z Q.Microstructure and properties of Al-9.0Zn-2.5Mg-1.2Cu-0.12Sc-0.15Zr alloy[J].The Chinese Journal of Nonferrous Metals,2007,17(3):396-401.
[6]STARKE E A,STALEY J T.Application of modern aluminum alloys to aircraft[J].Progress in Aerospace Sciences,1996,32:131-172.
[7]潘复生,张丁非.铝合金及应用[M].北京:化学工业出版社,2006.PAN F S,ZHANG D F.Aluminum Alloy and Its Application[M].Beijing:Chemical Industry Press,2006.
[8]CONG F G,ZHAO G,JIANG F,et al.Effect of homogenization treatment on microstructure and mechanical properties of DC cast7X50aluminum alloy[J].Transactions of Nonferrous Metals Society of China,2015,25:1027-1034.
[9]黄元春,刘宇,肖政兵,等.时效处理对Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr合金超声铸锭轧件组织与抗腐蚀性能的影响[J].粉末冶金材料科学与工程,2015,20(2):280-287.HUANG Y C,LIU Y,XIAO Z B,et al.Effect of aging treatment on microstructure and corrosion properties of plate rolling with ultrasonic casting Al-7.8Zn-1.6Mg-1.8Cu-0.12Zr aluminum alloy ingot[J].Materials Science and Engineering of Powder Metallurgy,2015,20(2):280-287.
[10]舒文祥,侯陇刚,刘君城,等.先进高强韧Al-Zn-Mg-Cu合金凝固和均匀化组织及相构成[J].北京科技大学学报,2014,36(11):1534-1539.SHU W X,HOU L G,LIU J C,et al.Microstructure and phase components of as-cast and homogenized advanced Al-Zn-Mg-Cu alloys with high strength and toughness[J].Journal of University of Science and Technology Beijing,2014,36(11):1534-1539.
[11]张新明,吴泽政,刘胜胆,等.固溶处理对7A55铝合金局部腐蚀性能的影响[J].材料工程,2014,(4):26-33.ZHANG X M,WU Z Z,LIU S D,et al.Influence of solution heat treatment on localized corrosion of 7A55aluminum alloy[J].Journal of Materials Engineering,2014,(4):26-33.
[12]滕海涛,熊柏青,张永安,等.高Zn含量Al-Zn-Mg-Cu系铝合金的凝固态显微组织[J].中国有色金属学报,2015,25(4):852-865.TENG H T,XIONG B Q,ZHANG Y A,et al.Solidification microstructure of high zinc-containing Al-Zn-Mg-Cu alloys[J].The Chinese Journal of Nonferrous Metals,2015,25(4):852-865.
[13]LI Y X,LI P,ZHAO G.The constituents in Al-10Zn-2.5Mg-2.5Cu aluminum alloy[J].Mater Sci and Eng:A,2005,397(1-2):204-208.
[14]MONDAL C,MUKHOPADHYAY A K.On the nature of T(Al2Mg3Zn3)and S(Al2CuMg)phases present in as-cast and annealed 7055aluminum alloy[J].Materials Science and Engineering:A,2005,391(1-2):367-376.
[15]李国爱.700MPa级超高强铝合金锻件成分设计及制备工艺研究[D].北京:北京航空材料研究院,2012.LI G A.Research on the composition design and preparation technology of 700MPa ultra-high strength aluminum alloy[D].Beijing:Beijing Institute of Aeronautical Materials,2012.
[16]宁爱林.析出相及其分布对高强铝合金力学性能的影响[D].长沙:中南大学,2007.NING A L.The effect of precipitation and its distribution to high strength aluminum alloy[D].Changsha:Central South University,2007.
[17]KNIGHT S P,BIRBILIS N,MUDDLE B C,et al.Correlations between intergranular stress corrosion cracking,grain-boundary microchemistry,and grain-boundary electrochemistry for Al-ZnMg-Cu alloys[J].Corrosion Science,2010,52(12):4073-4080.
[18]王祝堂,田荣璋.铝合金及其加工手册[M].长沙:中南大学出版社,2005.WANG Z T,TIAN R Z.Aluminum Alloy and Its Processing Manual[M].Changsha:Central South University Press,2005.
[19]PAUL A,ZHANG Y.Heat treatment of 7xxx series aluminum alloys-some recent developments[J].Transactions of Nonferrous Metals Society of China,2014,24:2003-2017.
[20]GROSVENOR A.Microstructural evolution during retrogression and reaging treatment of aluminum alloy 7075[D].Melbourne:Monash University,2008.
[21]AMS 2772E.Heat Treatment of Aluminum Alloy Raw Materials[M].Warrendale,USA:International,2008.16-20.
[22]KNIGHT S P.Stress corrosion cracking of Al-Zn-Mg-Cu alloys:effects of heat-treatment,environment,and alloy composition[D].Melbourne:Monash University,2008.
[23]KNIGHT S P,BIRBILIS N,MUDDLE B C,et al.Correlations between intergranular stress corrosion cracking,grain-boundary microchemistry,and grain-boundary electrochemistry for Al-ZnMg-Cu alloys[J].Corrosion Science,2010,52:4073-4080.
[24]HUANG L P,CHEN K H,LI S.Influence of grain-boundary pre-precipitation and corrosion characteristics of inter-granular phases on corrosion behaviors of an Al-Zn-Mg-Cu alloy[J].Materials Science and Engineering:B,2012,177:862-868.
[25]De GEUSER F,DESCHAMPS A.Precipitate characterization in metallic systems by small-angle X-ray or neutron scattering[J].Comptes Rendus Physique,2012,13:246-256.
[26]DESCHAMPS A,de GEUSER F.Quantitative characterization of precipitate microstructures in metallic alloys using small-angles scattering[J].Metallurgical and Materials Transactions A,2013,44:77-86.