摘要
采用金相、扫描电镜、透射电镜分析及拉伸性能和断裂韧度试验等手段,研究了7A99铝合金锻件双级时效处理后的组织和性能。结果表明:7A99铝合金锻件经过120℃/4h+165℃/8 h双级时效处理后的抗拉强度、屈服强度、伸长率和电导率分别为548 MPa,513 MPa,12.0%和38.2%IACS;锻件的L-T向断裂韧度为30.5 MPa·m1/2,锻件显示了较好的强韧匹配和耐蚀性;合金的断裂方式为穿晶韧窝断裂方式;主要沉淀相为η'相和η相。
Effects of two-step aging treatment on the microstructure and mechanical properties of 7 A99 forged aluminum alloy were studied using optical microscopy(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM),tensile test and fracture toughness test. The results show that after 120 ℃/4 h + 165 ℃/8 h two-step aging treatment,the ultimate tensile strength,yield strength,elongation and electrical conductivity are 548 MPa,513 MPa,12. 0% and 38. 2% IACS,respectively.Meanwhile,the L-T toughness fracture is 30. 5 MPa·m1/2. The fracture mode of the alloy is transgranular dimple fracture mechanism,and the major precipitates are η' and η phases under the aging condition.
引文
[1]FRIDLYANDER J N,SENATOROVA O G.Development and application of high-strength Al-Zn-Mg-Cu alloys[J].Materials Science Forum,1996,217/222:1813-1818.
[2]HEINZ A,HASZLER A,MOLDENHAUER S,et al.Recent development in Aluminum alloys for aerospace applications[J].Materials Science and Engineering:A,2000,280(1):102-107.
[3]李成功,巫世杰,戴圣龙,等.先进铝合金在航空航天工业中的应用与发展[J].中国有色金属学报,2002,12(1):14-21.(LI C G,WU S Z,DAI S L,et al.Application and development of advanced aluminum alloy in aerospace industry[J].The Chinese Journal of Nonferrous Metals,2002,12(1):14-21.)
[4]马志锋,赵唯一,陆政.织构及组织结构对超高强铝合金平面力学性能的影响[J].航空材料学报,2015,35(3):1-6.(MA Z F,ZHAO W Y,LU Z.Impact of texture and microstructure on in-plane anisotropy of ultra-strength aluminum alloy[J].Journal of Aeronautical Materials,2015,35(3):1-6.)
[5]LUKASAK D A,HART R M.Aluminum alloy development efforts for compression dominated structure of aircraft[J].Light Metal Age,1991,2(9):11-15.
[6]张君尧.航空结构用高纯高韧性铝合金的进展(l)[J].轻金属,1994(6):54-58.(ZHANG J Y.Progress in high purity and toughness aluminum alloy of aeronautical construction(l)[J].Light Metals,1994(6):54-58.)
[7]周鸿章.高强铝合金的研究进展[J].稀有金属材料与工程,2001,30(6):87-92.(ZHOU H Z.Progress in high-strength aluminum alloy research[J].Rare Metal Materials and Engineering,2001,30(6):87-92.)
[8]陈军洲,戴圣龙,甄良.AA7055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.
[9]WANG S H,ZHANG X G,YANG S J,et al.Microstructure and mechanical properties of forged Al-7.1Zn-1.1Mg-1.6Cu-0.14Zr alloy after two-step ageing treatment at 120and 170℃[J].Rare Metals,2010,29(4):433-437.)
[10]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℃and 150℃[J].Materials Science and Engineering:A,1999,270(1):55-63.
[11]CHEN J Z,ZHEN L,YANG S J,et al.Investigation of precipitation behavior and related hardening in AA 7055aluminum alloy[J].Materials Science and Engineering:A,2009,500(1/2):34-42.
[12]DESCHAMPS A,LIVET F,BRECHET Y.Influence of predeformation on ageing in an Al-Zn-Mg alloy:I.Microstructure evolution and mechanical properties[J].Acta Materialia,1998,47(1):281-292.
[13]SHERCLIFF H R,ASHBY M F.A process model for age hardening of aluminium alloys—I The model[J].Acta Metallurgica et Materialia,1990,38(10):1789-1802.