热处理升降温过程对BT22(TC18)钛合金组织性能的影响
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
Ti-5Al-5Mo-5V-1Cr-1Fe(BT22)是前苏联1974年研制成功的近β型钛合金。该合金具有深度淬透性和明显的时效强化效应,因此可制成大型锻件、模锻件和高强承力件。在进行新的工艺探索时,大锻件由于尺寸大,对不同尺寸的大规格锻件进行等尺寸实物试验是不经济的,而实验常规试样试验结果会与实际生产过程相差很大,并且具有一定的局限性。
     基于上述考虑,本文通过实测和ANSYS有限元模拟两种手段研究了Φ170mm×250mm大尺寸锻棒固溶后降温和时效升温过程中内部温度场的变化情况,OM、SEM、TEM及X射线衍射用于对固溶后降温和时效升温过程合金显微组织、断口表面及相进行分析。维氏硬度和室温拉伸用于机械性能的分析。
     研究结果表明,Φ170mm×250mm锻棒热处理降温过程中其内外温差可达50℃左右,采用ANSYS有限元分析软件能准确的反映工件热处理中的热过程。通过模拟得到降温过程的温度值与实测值相对误差在2%~5%左右。由于相变的原因875℃固溶空冷曲线有一段近似平台,这一平台把875℃固溶后空冷降温过程分三阶段。
     Φ170mm×50mm锻棒875℃固溶降温过程中发现从心部到边部析出α相逐渐增多,并且随着温度的降低析出的α相越细密。合金在810℃固溶后空冷降温过程中α相的增多不明显但是尺寸宽化明显。875℃和810℃降温硬度曲线表现出硬度先升高再趋于平缓的特点。
     实验用小尺寸(Φ12mm×70mm)试样经875℃固溶30分钟后为全β组织,550℃时效过程中α相析出并长大,试样硬度逐渐升高,室温拉伸显示断裂为脆性沿晶断裂。Φ170mm×250mm锻棒经875℃固溶2小时后空冷,发现其组织中已经有α相析出,时效过程中初生α相变化不大,主要是次生α相的生成和长大,时效过程中硬度变化曲线平缓在360~400范围内波动。经550℃时效6小时后锻棒三个部位强度基本一致,但是塑性边部明显不如心部和1/2R。
     Φ12mm×70mm试样经810℃固溶30分钟后为针状初生α相和β相的两相组织,550℃时效24分钟,析出次生α相,硬度也迅速提高,时效65分钟硬度达到峰值,550℃时效6小时硬度无明显升高,拉伸数据显示断裂为韧性断裂。
     Φ170mm×250mm锻棒经810℃固溶90分钟后空冷,组织为“叉形”结构的α相和β相组成的两相组织。550℃时效24分钟,晶界处先析出了次生α相,550℃时效2小时后硬度达到峰值,随后时效硬度无明显升高趋势。拉伸数据显示边部的强度高于心部,但塑性又不如心部。
Ti-5Al-5Mo-5V-1Cr-1Fe(BT22) is a nearβ-type titanium alloy,which has been successfully developed by Soviet Union in 1974.This Alloy can be applied in heavy forgings、die forging and high strength force bearing parts,due to its high hardenability、microstructure inhomogeneity and effects of aging strengthen.In new process research, practicality experiment of heavy forgings is impossible,and the experiment results of small specimens in lab(Φ12×70mm) are different from actual productions.
     Based on the above considerations,the inner temperature field ofΦ170mm×250mm forging during cooling after solution and heating in aging was studied, according to measured and simulated by ANSYS finite element.OM,SEM,TEM observation and X-ray diffraction were performed to characterize the microstructures, fracture surfaces and phase of this alloy.Vickers hardness and room temperature tensile were performed to characterize the mechanical.
     The results revealed as following:Difference of internal and external temperature of this forging can reached about 50℃during the cooling process.The thermal process during procedure of heat treatment can be reflected accurately by ANSYS finite element software.The relative error between simulated and measured temperature value during cooling process is about 2%~5%.After 875℃solution,the air cooling curve have an approximate platform,and this cooling process was divided into three stages.
     From center to edge,theαphase was gradually increased during cooling ofΦ170mm×250mm forging bar after solution at 875℃,and theαphase was fine and dense with the decreased temperature.After solution at 810℃,the increased number of a phase was not obvious but the broaden ofαphase was obviously.The characteristic of samples hardness curve during 875℃and 810℃solution cooling process was raised firstly and then kept stable.
     After solution 30 minutes at 875℃the microstructure ofΦ12mm×70mm isβ phase,aging at 550℃theαphase was precipitation and growth,the hardness of specimens was gradually increased.After aging 6 hours at 550℃,the experimental date of room temperature tensile was only tensile strength.Reference for fracture scanning, the result showed that the fracture was brittle intergranular fracture.During air cooling after solution at 875℃2 hours,αphase of forging has already precipitated,the primaryαchanged little,but the secondaryαprecipitated and grew up during aging process.The curve of hardness fluctuated gently in HV360~400.the strength of three parts of forging were basically identical,but the plastic of edge was poorer than core and 1/2R.
     The microstructure ofΦ12mm×70mm speciments were two phase structures after 810℃solution.Aging at 550℃after 24 minutes,secondaryαwere precipitated and hardness was improved;After 65 minutes,hardness reached the peak;After 6hours, hardness was no significantly increased and the fracture was ductile fracture.
     After solution at 810℃,90 minutes,the microstructure of forging bar were two phase structures,fork typeαandβphase.Aging at 550℃after 24 minutes secondary were precipitated along grain boundary;after 2 hours,the hardness reached the peak. After solution and aging,the date of tensile revealed that the strength and tensile of three parts of forging were uniform.
引文
[1]C.莱茵斯,M.皮特尔斯[德].钛与钛合金.陈振华等译,北京.化学工业出版社,2005.32
    [2]张翥.β钛合金的概述[J].稀有金属,1995,4(19):296-299
    [3]P.J.Bania,J.Met.1994,41:11-19
    [4][4]D.Eylon,in:S.Ferichiro,T.Kishi(Eds),Metallurgy and Technology of Practical Titanium Alloy.TMS,Warrendate,PA,1994,pp:29-34.
    [5]汪建林.高强度钛合金的发展和应用.上海钢研,2001,(2):25
    [6]陈玉文.β钛合金及其在宇航工业中的应用.稀有金属,1996,20(4):297
    [7]屈乃琴.β钛合金的新发展.钛工业进展,1996,(06):21
    [8]Rosenbery H W,Beta Titanium Alloy in the 1980'.New York:Metallurgical society of AIME,1984.397
    [9]Morgen G C et al,Fourth International Conference on Titanium,Kyoto,Japan,1980.1443
    [10]Wilson D H et al,Beta Titanium Alloy in the 1980'.New York:Metallurgical society of AIME,1984.457
    [11]Isaac G H et al,Fifth International Conference on Titanium,Munich,FRG,1984.1605
    [12]Sosenbery H W,Beta Titanium Alloy in the 1980'.New York:Metallurgical society of AIME,1984.409
    [13]Okada M et al,Fifth International Conference on Titanium,Munich,FRG,1984.1835
    [14]张翥等.第六届全国钛及钛合金学术交流会,西安,1984,(1987).149
    [15]汪建林等.第七届全国钛及钛合金学术交流会,广州,1990,(1991).185
    [16]张树启等.第七届全国钛及钛合金学术交流会,广州,1990,(1991).675
    [17]Toran J R et al,Fourth International Conference on Titanium,Kyoto,Japan,1980(1980).1491
    [18]魏寿庸等.Ti-5Al-5V-5Mo-1Cr-1Fe钛合金简介.钛工业进展,1998(4):8
    [19]张翥等.第七届全国钛及钛合金学术交流会,广州,1990,(1991).427
    [20]Parris W M et al.United States Patent,4980127,DEC25,1990
    [21]Y.Combres,B.Champin.β-CEZ Properties.In:Eylon D,Boyer R R,Koss D A.Beta Titanium Alloy in the 1990's.Warrendale:TMS,1993.477-483
    [22]M.K.Mequillan,M.A,Met.Reviews,1963,(8):41
    [23]张喜燕,赵永庆,白晨光编.钛合金及其应用.北京.化学工业出版社,2005.92
    [24]张廷杰.钛合金相变的电子显微镜研究(Ⅲ).稀有金属材料与工程,1989,(4):71-78
    [25]J.C.Williams.Kinatics and phase trasnsformation.Titanium Science and technology,1973,vol3:1433-1494
    [26]黄金冶炼厂译,国外钛合金文集.北京.冶金工业出版社,1972.124
    [27]张少卿等.近β型钛合金Ti-10V-2Fe-3Al的时效相变研究.金属学报,1989,25(1)
    [28]张廷杰.钛合金相变的电子显微镜研究(Ⅳ)-钛合金的ω相变.稀有金属材料与工程,1989(5):77-82
    [29]J.C.Williams,Kinatics and phase trasnsformation.Titanium Science and technology,1973,vol3:1433-1494
    [30]Blackman M.J.Trans,AIME:1968,V242 2-61
    [31]张启海等.βⅢ钛合金中的相变.钛科学与工程,1987(2):295
    [32]沈桂琴等.Ti-15Mo-2.7Nb-3Al-0.2Si高强钛合金的相变.材料工程,1999,(3):19-24
    [33]常辉等,近β型钛合金Ti-B19时效过程中的相变及显微组织.稀有金属材料与工程,2006,(10)
    [34]O.M.Ivasishin et al,Precipitation and Recrystallization Behavior of Beta titanium Alloys during Continuous Heat Treatment.Metall Trans,34A(2003) 147 - 158
    [35]Flower H M,Swann P R,West D R F.Metall Trans,1971,2:3289
    [36]Ramachandra C,Singh Vakil.Metall Trans,A,1982,13A:771
    [37]王金有,葛志明,周彦邦编.航空用钛合金.上海.上海科学技术出版社,1985.163
    [38]田荣璋编.金属热处理.北京.冶金工业出版社,1985
    [39]T.Ahmed,H.J.Rack.Phase transformation during cooling in α+βtitanium alloys,Met.1998,A243:206-211
    [40]刘东升.高强韧钛合金的热处理工艺及相变行为研究.清华大学工程硕士论文,2005
    [41]朱峰,计波,朱益藩.Ti-5Mo-5V-5Al-1Cr-1Fe合金热处理工艺研究.上海钢研,2006,3:45
    [42]P.R.Boyer,Application Of Beta Titanium Alloys In Airframes.Beta Titanium Alloys in the 1990's-Titanium Committee of TMS,2003:333-345
    [43]J.C.Fanning.Properties of TIMETAL 555(Ti-5Al-5Mo-5V-3Cr-0.6Fe).Journal of Materials Engineering and Performance.2005,14(6):788-791
    [44]鲍利索娃E A(陈石卿译).钛合金金相学.北京.国防工业出版社,1980
    [45]Lyasot skaya V S,Knyazeva S I,Fedorava L V.The selection of thermocycling treatment types applied to the welded joint s of titanium alloys
    [46]Kubiak K,Hadasik E,Sieniawski J,et al.Influence of Microstructure on hot plasticity of Ti-26Al-24V and Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloys[A]
    [47]L(u|¨) tjering G,Albrecht J.Ti2003 Science and Technology.Hamburg:DGM,2004.371-376
    [48]Horwath W,Marketz W,Gach E.Takeoff on titanium
    [49]Fanning J C,Boyer R R.Properties of TIMETAL555-a new near-beta titanium alloy for airframe components
    [50]#12
    [51]#12
    [52]Г.Е.玛扎洛娃(周梦雄等译).钛合金的压力加工.北京.航天工艺编辑部,1992:33-34
    [53]沙爱学,李兴无,王庆如等,热变形温度对TC18钛合金显微组织和力学性能的影响.中国有色金属学报,2005,8(35):1168-1171.
    [54]李渭清,冯永琦,王鼎春等,镦粗变形工艺对TC18组织和性能的影响,钛工业进展.2008,8(4):24-26
    [55]N.M.Grinberg;S.G.Zmeevets;I.L.Ostapenko,Phase composition and fatigue strength of alloy VT22.Metallovedenie I Termicheskaya Obrabotka Metallov.1976,12:4-8
    [56]郑永灵,BT22钛合金锻造工艺参数试验研究[A],第二届全国塑性加工学术年会2002;北京
    [57]黄伯云,李成功等.中国材料工程大典 有色金属材料工程 上.北京.化学工业出版社,2005
    [58]于兰兰,毛小南,张鹏省等.热处理工艺对BT22钛合金组织和性能的影响.稀有金属快报,2005,24(3):21
    [59]《稀有金属材料加工手册》编写组。稀有金属材料加工手册.北京.冶金工业出 版社,1984.48
    [60]任雁秋,李义科,贺友多.包头钢铁学院学报,1999,18(4):423
    [61]贺友多,刘中兴,李保卫.钢铁,1989,24(3):55
    [62]余万华,刘新忠,戴石峰.加热钢坯内部温度的计算机模拟.轧钢.2005,22(5):17
    [63]吴景之.温度场计算机模拟在国外大锻件生产中的应用.大型铸锻件.1993,2
    [64]曹延欣.有限元分析软件ANSYS及其使用.大众科技.2008,2
    [65]吴景之.大件加热.大型铸锻件.1992,2
    [66]张朝晖.ANSYS8.0热分析教程与实例解析.北京.中国铁道出版社,2005.3
    [67]Sauer C,L(u|¨)tjering G.Mater Sci Eng.2001,A319-321:393
    [68]杨义,徐峰,黄爱军等.金属学报,2005,41(7):71
    [69]Koike J,Maruyama K.Mater Sci Eng,1999,A263:155
    [70]葛鹏,赵永庆,周廉.β钛合金的强化机理.材料导报,2005,19(12)
    [71]J.I.Qazi,V.Tsakiris,B.Marquardt et al.The Effect of Aging on the Tensile Behavior of Ti-35Nb-7Zr-5Ta-(0.06-0.7)O Alloys.Titanium Science and technology,vol3,2003.1651-1658
    [72]Y.L.Hao,M.Niinomi,D.Kuroda et al.Met Mat Trans.34A,2003,1007
    [73]石德珂,金志浩.材料力学性能.西安.西安交通大学出版社,1998.19-20
    [74]Li Y G,Loretto M H,Rugg D,Voice W.Acta Mater,2001,49:3011-3017

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700