Effect of compressed pre-deformation on precipitation behavior of 7050 aluminum alloy during non-isothermal aging
FENG Hao1, FU Dian-bao2, CHENG Jia-le2, TANG Yin-lin2, CHEN Jun-feng2, WANG Chen2, ZOU Lin-chi3
1. Department of Logistics, Fuzhou University, Fuzhou 350116, China;
2. College of Materials Science and Engineering, Fuzhou University, Fuzhou 350116, China;
3. College of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350118, China
Abstract:TEM, DSC and other techniques were used to characterize the heating aging precipitation behavior of 7050 aluminum alloy under compression pre-deformation conditions, and the influence law and mechanism of pre-deformation on heating aging precipitation were investigated. The results show that 7050 aluminum alloy can obtain excellent strength and corrosion resistance after pre-deformation heating aging, which can significantly shorten time and reduce energy consumption compared with traditional aging process. The pre-deformation greatly promotes the aging precipitation of 7050 aluminum alloy. The precipitate size increases rapidly as the increase of deformation during the same heating aging process, and its size distribution range increases rapidly too. The pre-deformation during heating aging process not only reduces the phase transformation activation energy of η' and η phases of 7050 aluminum alloy, but also accelerates the diffusion of solute atoms, which intensifies the Ostwald ripening and promotes the growth of precipitates. The calculation results show that the phase transformation activation energy of 7050 aluminum alloy gradually decreases with the increase of deformation. When the deformation amount increases from 0% to 18%, the phase transition activ-ation energy of η' and η phases decreases from 116.0 kJ/mol to 101.7 kJ/mol and 120.8 kJ/mol to 107.5 kJ/mol, respectively.
[1] 陈军洲,戴圣龙,甄良.AA 7055铝合金板材的微观组织与力学性能[J].航空材料学报,2017,37(5):7-14. CHEN J Z,DAI S L,ZHEN L.Microstructure and mechanical property of aluminum alloy plate AA 7055[J]. Journal of Aeronautical Materials, 2017, 37(5):7-14.
[2] 张新明,邓运来,张勇.高强铝合金的发展及其材料的制备加工技术[J].金属学报,2015,51(3):257-271. ZHANG X M,DENG Y L,ZHANG Y.Development of high strength aluminum alloys and processing techniques for the materials[J].Acta Metallurgica Sinica,2015,51(3):257-271.
[3] 杨守杰,邢清源,于海军,等.800 MPa级Al-Zn-Mg-Cu系合金[J].材料工程,2018,46(4):82-90. YANG S J,XING Q Y,YU H J, et al.Al-Zn-Mg-Cu alloys with strength of 800 MPa[J].Journal of Materials Engineering,2018,46(4):82-90.
[4] 范淑敏,陈送义,张星临,等.多级时效热处理对7056铝合金析出组织与耐蚀性的影响[J].材料工程,2019,47(6):136-143. FAN S M,CHEN S Y,ZHANG X L,et al.Influence of multi-stage aging heat treatment on precipitation microstructure and corrosion resistance of 7056 aluminum alloy[J].Journal of Materials Engineering,2019,47(6):136-143.
[5] 何正林,高文理,陆政,等.热处理对7A85铝合金组织和性能的影响[J].材料工程,2015,43(8):13-18. HE Z L,GAO W L,LU Z,et al.Effects of heat treatment on microstructure and properties of 7A85 aluminum alloy[J].Journal of Materials Engineering,2015,43(8):13-18.
[6] CAI Y H,LANG Y J,CAO L Y,et al.Enhanced grain refinement in AA7050 Al alloy by deformation-induced precipitation[J].Materials Science and Engineering:A,2012,549:100-104.
[7] AFIFI M A,YING C W,PEREIRA P H R,et al.Effect of heat treatments on the microstructures and tensile properties of an ultrafine-grained Al-Zn-Mg alloy processed by ECAP[J].Journal of Alloys and Compounds,2018,749:567-574.
[8] 韩念梅,张新明,刘胜胆,等.预拉伸对7050铝合金断裂韧性的影响[J].中国有色金属学报,2010,20(11):2088-2093. HAN N M,ZHANG X M,LIU S D,et al.Effect of prestretching on fracture toughness of 7050 aluminum alloy[J].The Chinese Journal of Nonferrous Metals,2010,20(11):2088-2093.
[9] JIANG J T,TANG Q J, YANG L, et al. Non-isothermal ageing of an Al-8Zn-2Mg-2Cu alloy for enhanced properties[J].Journal of Materials Processing Technology,2016, 227:110-116.
[10] JIANG D M,LIU Y, LIANG S, et al. The effects of non-isothermal aging on the strength and corrosion behavior of Al-Zn-Mg-Cu alloy[J].Journal of Alloys and Compounds,2016,681:57-65.
[11] JIANG J T,XIAO W Q, YANG L, et al. Ageing behavior and stress corrosion cracking resistance of a non-isothermally aged Al-Zn-Mg-Cu alloy[J].Materials Science and Engineering:A,2014,605(1/2):167-175.
[12] WANG D,NI D R,MA Z Y.Effect of pre-strain and two-step aging on microstructure and stress corrosion cracking of 7050 alloy[J].Materials Science and Engineering:A,2008,494(1/2):360-366.
[13] OSTEN J,MILKEREIT B,SCHICK C,et al.Dissolution and precipitation behaviour during continuous heating of Al-Mg-Si alloys in a wide range of heating rates[J].Materials,2015,8(5):2830-2848.
[14] KEMSIES R H,MILKEREIT B,WENNER S,et al.In situ DSC investigation into the kinetics and microstructure of dispersoid formation in Al-Mn-Fe-Si(-Mg) alloys[J].Materials & Design,2018,146:96-107.
[15] WU Y P,YE L Y,JIA Y Z,et al.Precipitation kinetics of 2519A aluminum alloy based on aging curves and DSC analysis[J].Transactions of Nonferrous Metals Society of China,2014,24(10):3076-3083.
[16] GHOSH K S,KUMAR A K,MOHAN M K.Calorimetric studies and kinetic parameters of solid state reactions in 7017 Al-Zn-Mg alloy[J].Transactions of Indian Institute of Metals,2008,61(6):487-496.
[17] KHALFALLAH A,RAHO A A,AMZERT S,et al.Precipitation kinetic of GP zones, metastable η' phase and equilibrium η phase in Al-5.46wt%Zn-1.67wt%Mg alloy[J].Transactions of Nonferrous Metals Society of China,2019,29(2):233-241.
[18] KAMP N,SULLIVAN A,TOMASI R,et al.Modelling of heterogeneous precipitate distribution evolution during friction stir welding process[J].Acta Materialia,2006,54(8):2003-2014.
[19] LI M H,YANG Y Q,FENG Z Q,et al.Influence of equal-channel angular pressing on aging precipitation in 7050 Al alloy[J].Intermetallics,2014,55:49-55.
[20] PENG X Y,LI Y,LIANG X P,et al.Precipitate behavior and mechanical properties of enhanced solution treated Al-Zn-Mg-Cu alloy during non-isothermal ageing[J].Journal of Alloys and Compounds,2018,735:964-974.