Al-7.0Zn-2.9Mg合金板在制备过程中的显微组织及力学性能
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摘要
采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和差示扫描量热仪(DSC)等分析手段研究了Al-7.0Zn-2.9Mg合金板在制备过程中及不同时效热处理工艺下的显微组织及力学性能。结果表明,Al-7.0Zn-2.9Mg合金铸态组织主要由α(Al)+Mg_(32)(Al,Zn)_(49)(T)相共晶组织、Al(Fe,Mn)Si相和少量过剩T相组成。经均匀化处理后,共晶相基本溶入基体中,基体中又重新析出MgZn_2粒子及少量Al_3Zr相。热轧后的晶粒组织沿轧制方向呈纤维状分布。试验了一种低温时效+常规时效的LTA工艺,结果显示,LTA态的合金强度和伸长率均略高于峰值时效(T6)和回归再时效(RRA)态。同时,析出相尺寸明显大于T6、RRA和双极时效(T73)态,且晶界析出相呈粗大不连续分布,具有较好的抗应力腐蚀开裂(SCC)潜力。
Microstructure and mechanical properties of Al-7. 0Zn-2. 9Mg alloy sheets during preparation and after different aging processes were investigated by means of optical microscope( OM),scanning electron microscopy( SEM),transmission electron microscopy( TEM),X-ray diffraction( XRD),differential scanning calorimetry( DSC). The results show that the as-cast Al-7. 0Zn-2. 9Mg alloy consists ofα( Al) + Mg_(32)(Al,Zn)_(49)( T) phase eutectic structure,Al( Fe,Mn) Si phase and a few excess T phases. After homogenization,the eutectic phase is dissolved into the α( Al) matrix,meanwhile,fine MgZn_2 particles and Al_3Zr phase precipitate in the α( Al) matrix. Grain structure of the alloy exhibits as fibrous structure along the rolling direction after hot rolling. A Low temperature preaging + conventional aging treatment( termed LTA) was employed as artificial aging for the alloy. The results show that the strength and elongation of the Al-7. 0Zn-2. 9Mg alloy under LTA temper are slightly higher than that of with T6 temper and RRA temper. Meanwhile,the size of precipitates in the Al-7. 0Zn-2. 9Mg alloy under LTA temper is larger than that of with T6 temper,RRA temper or T73 temper. Good stress corrosion cracking( SCC) resistance of the alloy under LTA temper can be expected because of the larger size and spacing of the grain boundary precipitates.
Microstructure and mechanical properties of Al-7. 0Zn-2. 9Mg alloy sheets during preparation and after different aging processes were investigated by means of optical microscope( OM),scanning electron microscopy( SEM),transmission electron microscopy( TEM),X-ray diffraction( XRD),differential scanning calorimetry( DSC). The results show that the as-cast Al-7. 0Zn-2. 9Mg alloy consists ofα( Al) + Mg_(32)(Al,Zn)_(49)( T) phase eutectic structure,Al( Fe,Mn) Si phase and a few excess T phases. After homogenization,the eutectic phase is dissolved into the α( Al) matrix,meanwhile,fine MgZn_2 particles and Al_3Zr phase precipitate in the α( Al) matrix. Grain structure of the alloy exhibits as fibrous structure along the rolling direction after hot rolling. A Low temperature preaging + conventional aging treatment( termed LTA) was employed as artificial aging for the alloy. The results show that the strength and elongation of the Al-7. 0Zn-2. 9Mg alloy under LTA temper are slightly higher than that of with T6 temper and RRA temper. Meanwhile,the size of precipitates in the Al-7. 0Zn-2. 9Mg alloy under LTA temper is larger than that of with T6 temper,RRA temper or T73 temper. Good stress corrosion cracking( SCC) resistance of the alloy under LTA temper can be expected because of the larger size and spacing of the grain boundary precipitates.
引文
[1]陈小明,宋仁国,李杰.7xxx系铝合金的研究现状及发展趋势[J].材料导报,2009,23(2):67-70.CHEN Xiao-ming,SONG Ren-guo,LI Jie.Current research status and develop trends of 7xxx series aluminum alloys[J].Materials Review,2009,23(2):67-70.
[2]黄继武.高强可焊7A52铝合金板材热处理及其相关基础研究[D].长沙:中南大学,2008.HUANG Ji-wu.Heat treatment research of 7A52 aluminum alloy plate with high strength and weldability and its related fundamental[D].Changsha:Central South University,2008.
[3]张平,李奇,赵军军,等.7A52铝合金中第二相分析及微区电位测试[J].中国有色金属学报,2011,21(6):1252-1257.ZHANG Ping,LI Qi,ZHAO Jun-jun,et al.Analysis of secondary phases and measurement of volta potential of 7A52 aluminum alloy[J].The Chinese Journal of Nonferrous Metals,2011,21(6):1252-1257.
[4]Zhou G X,Lang Y J,Hao J,et al.Interface analysis of 7B52 Al alloy laminated composite fabricated by hot-roll bonding[J].Transactions of Nonferrous Metals Society of China,2016,26(5):1269-1275.
[5]Stiller K,Warren P J,Hansen V,et al.Investigation of precipitation in an Al-Zn-Mg alloy after two-step ageing treatment at 100 degrees and 150degrees C[J].Journal of Power Sources,1999,274:156-164.
[6]Cina B.Reducing the susceptibility of alloys,particularly aluminum alloys,to stress corrosion cracking.US,3856584[P].1974.
[7]黄继武,尹志民,聂波,等.7A52铝合金原位加热过程中的物相转变与热膨胀系数测量[J].兵器材料科学与工程,2007,30(4):9-12.HUANG Ji-wu,YIN Zhi-min,NIE Bo,et al.Investigation of phases and thermal expansivity of 7A52 alloy in in-situ heating[J].Ordnance Material Science and Engineering,2007,30(4):9-12.
[8]LüX Y,Guo E J,Rometsch P,et al.Effect of one-step and two-step homogenization treatments on distribution of Al 3 Zr dispersoids in commercial AA7150 aluminium alloy[J].Transactions of Nonferrous Metals Society of China,2012,22(11):2645-2651.
[9]华成,张永安,李锡武,等.Al-7.5Zn-1.6Mn-1.4Cu合金的均匀化处理[J].稀有金属,2008,32(6):803-806.HUA Cheng,ZHANG Yong-an,LI Xi-wu,et al.Homogenizaing treatment of Al-7.5Zn-1.6Mg-1.4Cu alloy[J].Chinese Journal of Rare Metals,2008,32(6):803-806.
[10]熊创贤,万里,邓运来,等.Al-7.8Zn-1.6Mg-1.8Cu合金铸锭及其均匀化的微结构研究[J].中南大学学报(自然科学版),2010,41(2):465-471.XIONG Chuang-xian,WAN Li,DENG Yun-lai,et al.Investigation of microstructure in as-cast and homogenized Al-7.8Zn-1.6Mg-1.8Cu aluminum alloy[J].Journal of Central South University(Science and Technology),2010,41(2):465-471.
[11]王正安,汪明朴,杨文超,等.1973铝合金铸态组织及均匀化退火组织研究[J].材料工程,2010,5:56-63.WANG Zheng-an,WANG Ming-pu,YANG Wen-chao,et al.Microstructure of as cast and homogenized 1973 aluminum alloy[J].Journal of Materials Engineering,2010,5:56-63.
[12]戴晓元,喻井萍,寇莉莉.Sc微合金化对Al-Zn-Mg-Cu-Zr合金组织性能的影响[J].材料热处理学报,2010,31(6):89-94.DAI Xiao-yuan,YU Jing-ping,KOU Li-li.Effect of microalloying of Sc on microstructure and properties of Al-Zn-Mg-Cu-Zr alloys[J].Transactions of Materials and Heat Treatment,2010,31(6):89-94.
[13]李东峰,张新明,刘胜胆,等.锌镁含量对Al-Zn-Mg-Cu高强铝合金组织和性能的影响[J].材料热处理学报,2016,37(3):101-106.LI Dong-feng,ZHANG Xin-ming,LIU Sheng-dan,et al.Effect of Zn and Mg content on microstructure and properties of Al-Zn-Mg-Cu high strength aluminum alloys[J].Transactions of Materials and Heat Treatment,2016,37(3):101-106.
[14]Xiao T,Deng Y,Ye L,et al.Effect of three-stage homogenization on mechanical properties and stress corrosion cracking of Al-Zn-Mg-Zr alloys[J].Materials Science and Engineering A,2016,675:280-288.
[15]Deng Y L,Wan L,Wu L H,et al.Microstructural evolution of Al-Zn-Mg-Cu alloy during homogenization[J].Journal of Materials Science,2011,46(4):875-881.
[16]Waterloo G,Hansen V,Gjnnes J,et al.Effect of predeformation and preaging at room temperature in Al-Zn-Mg-(Cu,Zr)alloys[J].Materials Science and Engineering A,2001,303(1/2):226-233.
[17]Ou B,Yang J,Wei M.Effect of homogenization and aging treatment on mechanical properties and stress-corrosion cracking of 7050 Alloys[J].Metallurgical and Materials Transactions A,2007(38):1760-1773.
[18]Christodoulou L,Flower H M.Hydrogen embrittlement and trapping in Al6%Zn-3%Mg[J].Acta Metallurgica,1980,28(4):481-487.
[19]Li X,Xiong B,Zhang Y,et al.Effect of one step aging on microstructure and properties of a novel Al-Zn-Mg-Cu-Zr alloy[J].Science in China Series E:Technological Sciences,2009,52(1):67-71.
[20]Birbilis N,Buchheit R G.Electrochemical characteristics of intermetallic phases in aluminum alloys:An experimental survey and discussion[J],Journal of The Electrochemical Society,2005,152(4):140-151.
[21]Xu D K,Birbilis N,Lashansky D,et al.Effect of solution treatment on the corrosion behaviour of aluminium alloy AA7150:Optimisation for corrosion resistance[J].Corrosion Science,2011,53(1):217-225.
[22]肖代红,陈康华,罗伟红.固溶热处理对AA7085铝合金组织与性能的影响[J].稀有金属材料与工程,2010,39(3):494-497.XIAO Dai-hong,CHEN Kang-hua,LUO Wei-hong.Effect of solution heat treatment on microstructure and properties of AA7085 aluminum alloys[J].Rare Metal Materials and Engineering,2010,39(3):494-497.
[23]Marlaud T,Deschamps A,Bley F,et al.Evolution of precipitate microstructures during the retrogression and re-ageing heat treatment of an Al-Zn-MgCu alloy[J].Acta Materialia,2010,58(14):4814-4826.
[24]宁爱林,刘志义,冯春,等.Al-Zn-Mg-Cu合金组织和电导率及抗应力腐蚀性能研究[J].材料热处理学报,2008,29(2):108-113.NING Ai-lin,LIU Zhi-yi,FENG Chun,et al.Study of microstructure,electrical conductivity and stress corrosion of Al-Zn-Mg-Cu alloys[J].Transactions of Materials and Heat Treatment,2008,29(2):108-113.
[25]Brown M H,Staley J T,Liu J,et al.Aluminum alloy product having improved combinations of strength and corrosion resistance properties and method for producing the same.US,4863528[P].1989.
[26]陈康华,黄兰萍,郑强,等.高温预析出对7A52合金应力腐蚀性能的影响[J].中国有色金属学报,2005,15(3):441-445.CHEN Kang-hua,HUANG Lan-ping,ZHENG Qiang,et al.Effect of high temperature pre precipitation on stress corrosion cracking of 7A52 alloy[J].The Chinese Journal of Nonferrous Metals,2005,15(3):441-445.
[2]黄继武.高强可焊7A52铝合金板材热处理及其相关基础研究[D].长沙:中南大学,2008.HUANG Ji-wu.Heat treatment research of 7A52 aluminum alloy plate with high strength and weldability and its related fundamental[D].Changsha:Central South University,2008.
[3]张平,李奇,赵军军,等.7A52铝合金中第二相分析及微区电位测试[J].中国有色金属学报,2011,21(6):1252-1257.ZHANG Ping,LI Qi,ZHAO Jun-jun,et al.Analysis of secondary phases and measurement of volta potential of 7A52 aluminum alloy[J].The Chinese Journal of Nonferrous Metals,2011,21(6):1252-1257.
[4]Zhou G X,Lang Y J,Hao J,et al.Interface analysis of 7B52 Al alloy laminated composite fabricated by hot-roll bonding[J].Transactions of Nonferrous Metals Society of China,2016,26(5):1269-1275.
[5]Stiller K,Warren P J,Hansen V,et al.Investigation of precipitation in an Al-Zn-Mg alloy after two-step ageing treatment at 100 degrees and 150degrees C[J].Journal of Power Sources,1999,274:156-164.
[6]Cina B.Reducing the susceptibility of alloys,particularly aluminum alloys,to stress corrosion cracking.US,3856584[P].1974.
[7]黄继武,尹志民,聂波,等.7A52铝合金原位加热过程中的物相转变与热膨胀系数测量[J].兵器材料科学与工程,2007,30(4):9-12.HUANG Ji-wu,YIN Zhi-min,NIE Bo,et al.Investigation of phases and thermal expansivity of 7A52 alloy in in-situ heating[J].Ordnance Material Science and Engineering,2007,30(4):9-12.
[8]LüX Y,Guo E J,Rometsch P,et al.Effect of one-step and two-step homogenization treatments on distribution of Al 3 Zr dispersoids in commercial AA7150 aluminium alloy[J].Transactions of Nonferrous Metals Society of China,2012,22(11):2645-2651.
[9]华成,张永安,李锡武,等.Al-7.5Zn-1.6Mn-1.4Cu合金的均匀化处理[J].稀有金属,2008,32(6):803-806.HUA Cheng,ZHANG Yong-an,LI Xi-wu,et al.Homogenizaing treatment of Al-7.5Zn-1.6Mg-1.4Cu alloy[J].Chinese Journal of Rare Metals,2008,32(6):803-806.
[10]熊创贤,万里,邓运来,等.Al-7.8Zn-1.6Mg-1.8Cu合金铸锭及其均匀化的微结构研究[J].中南大学学报(自然科学版),2010,41(2):465-471.XIONG Chuang-xian,WAN Li,DENG Yun-lai,et al.Investigation of microstructure in as-cast and homogenized Al-7.8Zn-1.6Mg-1.8Cu aluminum alloy[J].Journal of Central South University(Science and Technology),2010,41(2):465-471.
[11]王正安,汪明朴,杨文超,等.1973铝合金铸态组织及均匀化退火组织研究[J].材料工程,2010,5:56-63.WANG Zheng-an,WANG Ming-pu,YANG Wen-chao,et al.Microstructure of as cast and homogenized 1973 aluminum alloy[J].Journal of Materials Engineering,2010,5:56-63.
[12]戴晓元,喻井萍,寇莉莉.Sc微合金化对Al-Zn-Mg-Cu-Zr合金组织性能的影响[J].材料热处理学报,2010,31(6):89-94.DAI Xiao-yuan,YU Jing-ping,KOU Li-li.Effect of microalloying of Sc on microstructure and properties of Al-Zn-Mg-Cu-Zr alloys[J].Transactions of Materials and Heat Treatment,2010,31(6):89-94.
[13]李东峰,张新明,刘胜胆,等.锌镁含量对Al-Zn-Mg-Cu高强铝合金组织和性能的影响[J].材料热处理学报,2016,37(3):101-106.LI Dong-feng,ZHANG Xin-ming,LIU Sheng-dan,et al.Effect of Zn and Mg content on microstructure and properties of Al-Zn-Mg-Cu high strength aluminum alloys[J].Transactions of Materials and Heat Treatment,2016,37(3):101-106.
[14]Xiao T,Deng Y,Ye L,et al.Effect of three-stage homogenization on mechanical properties and stress corrosion cracking of Al-Zn-Mg-Zr alloys[J].Materials Science and Engineering A,2016,675:280-288.
[15]Deng Y L,Wan L,Wu L H,et al.Microstructural evolution of Al-Zn-Mg-Cu alloy during homogenization[J].Journal of Materials Science,2011,46(4):875-881.
[16]Waterloo G,Hansen V,Gjnnes J,et al.Effect of predeformation and preaging at room temperature in Al-Zn-Mg-(Cu,Zr)alloys[J].Materials Science and Engineering A,2001,303(1/2):226-233.
[17]Ou B,Yang J,Wei M.Effect of homogenization and aging treatment on mechanical properties and stress-corrosion cracking of 7050 Alloys[J].Metallurgical and Materials Transactions A,2007(38):1760-1773.
[18]Christodoulou L,Flower H M.Hydrogen embrittlement and trapping in Al6%Zn-3%Mg[J].Acta Metallurgica,1980,28(4):481-487.
[19]Li X,Xiong B,Zhang Y,et al.Effect of one step aging on microstructure and properties of a novel Al-Zn-Mg-Cu-Zr alloy[J].Science in China Series E:Technological Sciences,2009,52(1):67-71.
[20]Birbilis N,Buchheit R G.Electrochemical characteristics of intermetallic phases in aluminum alloys:An experimental survey and discussion[J],Journal of The Electrochemical Society,2005,152(4):140-151.
[21]Xu D K,Birbilis N,Lashansky D,et al.Effect of solution treatment on the corrosion behaviour of aluminium alloy AA7150:Optimisation for corrosion resistance[J].Corrosion Science,2011,53(1):217-225.
[22]肖代红,陈康华,罗伟红.固溶热处理对AA7085铝合金组织与性能的影响[J].稀有金属材料与工程,2010,39(3):494-497.XIAO Dai-hong,CHEN Kang-hua,LUO Wei-hong.Effect of solution heat treatment on microstructure and properties of AA7085 aluminum alloys[J].Rare Metal Materials and Engineering,2010,39(3):494-497.
[23]Marlaud T,Deschamps A,Bley F,et al.Evolution of precipitate microstructures during the retrogression and re-ageing heat treatment of an Al-Zn-MgCu alloy[J].Acta Materialia,2010,58(14):4814-4826.
[24]宁爱林,刘志义,冯春,等.Al-Zn-Mg-Cu合金组织和电导率及抗应力腐蚀性能研究[J].材料热处理学报,2008,29(2):108-113.NING Ai-lin,LIU Zhi-yi,FENG Chun,et al.Study of microstructure,electrical conductivity and stress corrosion of Al-Zn-Mg-Cu alloys[J].Transactions of Materials and Heat Treatment,2008,29(2):108-113.
[25]Brown M H,Staley J T,Liu J,et al.Aluminum alloy product having improved combinations of strength and corrosion resistance properties and method for producing the same.US,4863528[P].1989.
[26]陈康华,黄兰萍,郑强,等.高温预析出对7A52合金应力腐蚀性能的影响[J].中国有色金属学报,2005,15(3):441-445.CHEN Kang-hua,HUANG Lan-ping,ZHENG Qiang,et al.Effect of high temperature pre precipitation on stress corrosion cracking of 7A52 alloy[J].The Chinese Journal of Nonferrous Metals,2005,15(3):441-445.