ti 55鈦合金板材超塑性變形行為

第20卷專輯 2010年10JournalofNonferrousOct.1，1,2，1，王清江1，1(1.中國(guó)金屬，沈陽2.沈陽大學(xué)機(jī)械，沈陽在高應(yīng)變速率下，Ti-55板材的最大伸長(zhǎng)率向高溫區(qū)移動(dòng)；超塑性變形過程中晶粒呈相互聚合長(zhǎng)大的現(xiàn)象，應(yīng)變號(hào)：TG ZHAOZi-bo1,GEJing-lu1,2,CHENZhi-yong1,WANGQing-jiang1,LIUJian-(1.InstituteofMetalResearch,TheAcademyofSciences,Shenyang110016,2.CollegeofMechanicalEngineering,ShenyangUniversity,Shenyang110044,:Thesuperstictensiletestswereperformedatvarioustemperatures(890?910℃)andinitialstrainrates(4.4×10?4?1.76×10?3s?1).Theresultsshowthatthefine-grainedTi-55sheet,withanaveragegrainsizeabout4μm,exhibitsexcellentsupersticity.Ontheoptimalsupersticconditionof900℃andinitialstrainrate8.8×10?4s?1,aumelongationof1300%canbeachieved.Thereexistsanoptimalstrainrateof8.8×10?4s?1foreachtesttemperaturetogetthehigheststrain,andthesupersticelongationwouldbesignificantlyreducedatstrainrateshigherorlowerthantheoptimumstrainrate.ThetemperatureforthebestsupersticityofTi-55sheetmovestohighertemperaturesathighstrainrates.Theinfluenceofthedeformationonmicrostructureisobviously.Thestraininducegraingrowthisoneofthemostprominentcharacteristicduringsupersticdeformation.:Ti-55titaniumalloy;supersticity;strainrate;deformationtemperature;Ti-55550℃下長(zhǎng)期服役的

之一而日益引起人們的重視。目前Ti-6Al-4V合和領(lǐng)域中[2]。高溫鈦合金由于具有比Ti-6Al-4V高的 Ti-55板材超塑性的影1，可見由等軸細(xì)4μm左右。

3個(gè)階段：的。圖2所示為Ti-55試樣超塑變形前、后的，33可可由Hart準(zhǔn)則得到很好解釋。F都是相同的。由1Fig.1Originalstructureof

FFAF

本試驗(yàn)所有超塑性拉伸試驗(yàn)均在島津DCS?25T3個(gè)變形溫度：890，900910℃，變形時(shí)采用恒定夾頭速度拉伸。8mm×4mm×1.37mm。每0.210.428.8×10?41.76×10?3s?1。試樣均沿垂直于軋制方向ZZeissAxiovert200MAT金相顯微鏡觀察變形前后顯微組織的變化。

2試樣變形前、后的 Photosofspecimensbeforeandaftersuperstic即dlnδdt，Hart3Fig.3Relationshipbetweenelongationandinitialstrain

力F及其變化率F都相同，所以由式(2)得：

δFdAAδδAAδddA δAδ δAδ ≥dln

超塑變形溫度對(duì)伸長(zhǎng)率及顯微組織的影響如圖5所示?？梢?，在低應(yīng)變速率時(shí)材料的伸長(zhǎng)率隨溫聚合[10?12](5所示)，又會(huì)大幅度降低材料超塑性勻性，則dlnδdt截面上應(yīng)變速率增加，使其強(qiáng)化速率大于松弛速率從而變形減慢，未發(fā)生細(xì)頸的部分應(yīng)變速率較慢，

4Fig.4Relationshipbetweenelongationand5 Microstructureoftensiledspecimen:(a)Chuckpartofspecimen,890℃,4.4×10?4s?1;(b)Chuckpartofspecimen,8908.8×10?4s?1;(c)Chuckpartofspecimen,910℃,4.4×10?4s?1;(d)Fracturepartofspecimen,890℃,4.4×10?4s?1;(e)Fracturepartofspecimen,890℃,8.8×10?4s?1;(f)Fracturepartofspecimen,910℃,4.4×10?4s?1材料內(nèi)部的協(xié)調(diào)變形能力進(jìn)一步增強(qiáng)，所以在較高初始應(yīng)變速率17610?3?1)條件下，T-55板材的最大9044×0?4?189088×0?4?1條件下樣品夾持部位與標(biāo)距5(),(d和(be(約4h)1組織明顯粗化13?15]，其平均晶粒尺寸長(zhǎng)大到8m左右。在應(yīng)變速率較快(保溫時(shí)間較短)的條件下，夾持端晶粒明顯比應(yīng)變速率較慢(保溫時(shí)間較長(zhǎng))時(shí)的細(xì)。這一晶粒長(zhǎng)大過程采用經(jīng)典晶粒長(zhǎng)大模型中大晶粒吞

也更加顯著，見圖5(c)。在超塑成形過由于晶界5(a)和(d)，5(b)和(e)可有良好的超塑變形能力，在900℃初始變形速率為閆偉,張海龍,,王清江,,李玉蘭,孫鳳久.Ti-55鈦合金板激光焊接[J].稀有金屬材料與工程,2008,37(3310?313.YANWei,ZHANGHai-long,LIUJiang-rong,WANGQing-jiang,CHENZhi-yong,LIYu-lan,SUNFeng-jiu.LastbeamweldingofTi-55titaniumalloysheet[J].RareMetalMaterialsandEngineering,2008,37(3):310?313.蔡建明,許超,郝孟一,黃旭,馬濟(jì)民,曹春曉.SP700和Ti-6Al-4V鈦合金細(xì)晶組織的疲勞裂紋擴(kuò)展特征[J].航空材料學(xué)報(bào),2006,26(3):71-74.CAIJian-ming,XUChao,HAOMeng-yi,HUANGXu,MAJi-min,CAOChun-xiao.FatiguecrackgrowthcharacteristicsoffinestructuresofSP700andTi-6Al-4Vtitaniumalloys[J].JournalofAeronauticalMaterials,2006,26(3):71?74.何鴻博.TC4鈦合金超塑性變形機(jī)制[M].大連:大連理工大學(xué),2008:5?40.HEHong-bo.Thesupersticdeformationmechanismandbehavioroffine-grainedTC4titaniumalloy[D].Dalian:DalianUniversityofTechnology,2008:5?40.IMAYEVRM,KAIBYSHEVOA,SALISHCHEVGMechanicalbehavioroffinegrainedTiAlintermetalliccompound-Ⅱ.Ductile-brittletransition[J].ActaMetallurgicaetMaterialia,1992,40(3):589?595.SHAGIEVMR,SENKOVON,SALLSHCHEVGA,FH.HightemperaturemechanicalpropertiesofasubmicrocrystallineTi-47Al-3Cralloyproducedbymechanical

alloyingandhotisostaticpressing[J].AlloysandCompounds,2000,313(1/2):201?208.NIEHTG,HSIUNGLM,WADSWORTHJ.SuperbehaviorofapowdermetallurgyTiAlalloywithametastablemicrostructure[J].Intermetallics,1999,7(2):163?170.崔麗,粟卓新,魏琦.高溫氧化對(duì)鈦合金超塑性能的影響[J].鈦工業(yè)進(jìn)展,2006,23(2):21?24.CUILi,LIZhuo-xin,WEIQi.InfluenceofhightemperatureoxidationonthesupersticabilityofTi-6Al-4Valloy[J].TitaniumIndustryProgress,2005,23(2):21?24.吳詩惇.金屬超塑性變形理論[M].:國(guó)防工業(yè),200712?32.WUShi-dun.Thetheoryofsupersticdeformationofmetal[M].Beijing:NationalDefenseIndustrialPress,2007:陳浦泉.組織超塑性[M].哈爾濱:哈爾濱工業(yè)大學(xué),1988110?114.CHENPu-quan.Microstructuresupersticity[M].Harbin:HarbinInstituteofTechnologyPress,1988:110?114..TC6鈦合金的超塑性研究[D].西安:西北工業(yè)大學(xué)2002:ZHANGZhi-qing.ThesupersticdeformationbehaviorofTC6[D].Xi’an:NorthwesternPolytechnicalUniversity,2002:趙文娟,丁樺,曹富榮,侯洪亮,李志強(qiáng).Ti-6Al-4V合金超塑性變形過的組織演變[J].中國(guó)有色金屬學(xué)報(bào),2007,17(121973?1980.ZHAOWei-juan,DINGHua,CAOFu-rong,HOUHong-ling,LIZhi-qing.MicrostructuralevolutionduringsupersticdeformationofTi-6Al-4Valloy[J].TheJournalofNonferrousMetals,2007,17(12):1973?1980.ZELINM.Graingrowthduringsupersticdeformation[J].InterfaceScience,2002,10:37?42.RICHTERS,HAMILTONCH.Deformationenhancedgraingrowthinatwophasetitaniumalloy[J].MaterialsScienceForum,1993,113/115:195?200.CAMPENNIVD,CàCERESCH.Strainenhancedgraingrowthatlargestrainsinasup