長期時(shí)效對(duì)一種新型鎳基合金的組織及持久性能的影響

1、第 27卷 第 5期2006年 10月材 料 熱 處 理 學(xué) 報(bào)TRANS ACTIONS OF M ATERIA LS AND HE AT TRE AT ME NTV ol . 27 N o . 5October2006長期時(shí)效對(duì)一種新型鎳基合金的組織及持久性能的影響崔 彤 1, 王繼杰 2, 王 磊 1, 楊洪才 1, 趙光普3(1. 東北大學(xué)材料與冶金學(xué)院 , 遼寧 沈陽 110006; 2. 沈陽航空工業(yè)學(xué)院材料工程系 , 沈陽 110034; 3. 北京鋼鐵研究總院 , 北京 100081摘 要 :研究一種新型鎳基合金在 750、 800、 850 長期時(shí)效 (500- 750 51

2、0MPa 持久性能的影響 。 。結(jié)果表明 :在 750-800 時(shí)效該合金有針狀 T CP 相 (, , 合金基體的強(qiáng)度降低 , ,1000h 處持久強(qiáng)度最 低 , 這與 , 試驗(yàn)合金 750 510MPa 的持久激活能降低 , 持久強(qiáng)度 下降 。關(guān)鍵詞 :; ; T CP 相 (拓?fù)涿芘畔?; 持久性能 ; 持久激活能中圖分類號(hào) :TG 13213; TG 14211 文獻(xiàn)標(biāo)識(shí)碼 :A 文章編號(hào) :100926264(2006 0520056204收稿日期 : 2005211214; 修訂日期 : 2006203230基金項(xiàng)目 : 國家 “ 十五” 科技攻關(guān)項(xiàng)目 (冶 N o 1005039

3、0B ; 遼寧省博 士啟動(dòng)基金項(xiàng)目 (20051010 ; 遼寧省航空專項(xiàng)基金項(xiàng)目 (2005400607作者簡(jiǎn)介 : 崔 彤 (1968, 男 , 講師 , 博士 , 主要從事高溫合金等 高性能材料領(lǐng)域的研究工作 , 發(fā)表論文 20余篇 , E 2mail :ct1149281631com 。 目前航空燃?xì)鉁u輪發(fā)動(dòng)機(jī)較多使用含鐵的鎳 2鐵基合金或不含鐵的鎳基合金 , 這種材料需要承受高溫 下氧化 、 氣體腐蝕及復(fù)雜應(yīng)力等的綜合作用 , 對(duì)材料 的強(qiáng) 度 及 穩(wěn) 定 性 有 較 高 要 求 。鎳 2鐵 基 G H4169(Inconel718 合金是當(dāng)前普遍使用的盤材合金 , 其使 用溫度不超

4、過 650 。 隨著航空事業(yè)的發(fā)展 , 對(duì)發(fā)動(dòng) 機(jī)設(shè)計(jì)的技術(shù)指標(biāo)也隨之提高 , 新合金需要在 700 以上安全使用 , 由于鐵基合金已不能滿足這一要求 , 鎳基合金成為研究的重點(diǎn) 。由該合金的成分 (表 1 可見該合金是以 相為主要強(qiáng)化相兼有碳化物強(qiáng)化 和基體的固溶強(qiáng)化 , 并且兼有較多的鎢 、 鉬等難溶金 屬元素 。 隨著合金元素的復(fù)雜 , 合金的長期時(shí)效處理將對(duì)其內(nèi)部的相 、 組織及高溫性能產(chǎn)生影響 124。合 金的高溫持久性能是評(píng)價(jià)該合金高溫下長期使用的 一項(xiàng)重要指標(biāo) , 是合金能否在高溫下長期使用的關(guān) 鍵 5,6。 為此 , 本文開展了這方面的研究工作 , 為復(fù)雜 鎳基合金在高溫下的使

5、用提供依據(jù) 。1 試驗(yàn)材料和方法試驗(yàn)合金試樣取自雙真空熔煉 , 經(jīng) 1200 均勻化處理后 , 鍛造開坯軋成直徑 21mm 棒材 。合金的化 學(xué)成分如表 1。表 1 試驗(yàn)合金的化學(xué)成分 (w t %T able 1 Chemical composition of the tested alloy(w t %C Cr C o M o W Al T i B M g Ni 0. 0619. 011. 08. 003. 001. 603. 350. 050. 01bal試驗(yàn)合金經(jīng)標(biāo)準(zhǔn)熱處理后 , 再進(jìn)行長期時(shí)效處理 。標(biāo)準(zhǔn)熱處理制度為 1080 ×4hAC (空 冷 +760×16

6、hAC (空冷 。長期時(shí)效熱處理制度見表 2(試驗(yàn)合金長期時(shí)效處理后采用空冷 。表 2 長期時(shí)效熱處理工藝T able 2 Long 2term aging heat treatment conditionsN o. Process 1750×500h 2750×1000h 3750×1500h 4750×2000h 5800×500h 6800×1000h 7800×1500h 8850×500h 9850×1000h 10850×1500h將熱處理后的合金加工成標(biāo)準(zhǔn) 5高溫持久拉伸 性能試樣

7、 。 在 C MT 5105電子萬能試驗(yàn)機(jī)上測(cè)定合金在 750 510MPa 持久拉伸性能 。再取金相樣觀察金 相組織變化 , 腐蝕劑為 3g CuS O 4+80ml HCl +40ml C 2H 5OH 。 采用 SSX 2550型掃描電子顯微鏡對(duì)合金顯微組織 、 高溫持久斷口進(jìn)行觀察分析 。2 試驗(yàn)結(jié)果211 試驗(yàn)合金時(shí)效處理后組織變化圖 1(a 為試驗(yàn)合金標(biāo)準(zhǔn)熱處理后的掃描電鏡照片 , 圖 1(b 為 750 經(jīng) 1500h 析可見 , , 合 相 初生 MC 、 M 23C 6和 M 6C5, 6。 1500-2000h 后在晶內(nèi)或晶界附近出現(xiàn)片狀 T CP 相 , 當(dāng)溫度升到 80

8、0 時(shí)T CP 相減少 、 晶界變粗 、 晶內(nèi)出現(xiàn)網(wǎng)狀碳物 , 850 以 后 T CP 相消失 , 由圖 1(c 、 1(d 可見 。 212 長期時(shí)效后合金持久性能及斷口形貌經(jīng)過標(biāo)準(zhǔn)熱處理后分別經(jīng) 750、 800和 850 長期 時(shí)效處理后合金在 750 下的持久性能如圖 2所示 。其結(jié)果表明 , 在 , 在時(shí)效時(shí)間 510MPa 下的持 , , 在 2000h 時(shí) , 見圖 2(a 。 和 850長期時(shí)效處理后合金在 750 510MPa 下的持久性能隨著時(shí)間的延長呈下降趨勢(shì) ,而延性對(duì)于 800 下 ,1000h 時(shí)為最低 ;850 下 ,500h時(shí)為最低 。圖 1 合金長期時(shí)效后的

9、 SE M 顯微組織Fig 11 SE M micrographs of different sam ples treated by long 2term aging(a 1080×4h 空冷 +760×16h , 空冷 (標(biāo)準(zhǔn)熱處理 ; (b 標(biāo)準(zhǔn)熱處理 +750×1500h , 空冷 (N o 13 ;(c 標(biāo)準(zhǔn)熱處理 +800×1500h , 空冷 (N o 17 ; (d 標(biāo)準(zhǔn)熱處理 +850×1500h , 空冷 (N o 110(a normal heat treatment :1080 +4h ,air cooling (AC +

10、760×16h ,AC ; (b normal heat treatment +750×1500h ,AC (N o 13 ;(c normal heat treatment +800×1500h ,AC (N o 17 ; (d normal heat treatment +850×1500h ,AC (N o 110 圖 2 不同溫度下時(shí)效對(duì)合金 750 510MPa 下的持久性能的影響Fig 12 750 510MPa stress 2rupture properties of alloy after long 2term aging at dif

11、ferent tem peratures(a 750 ; (b 800 ; (c 85075第 5期 崔 彤等 :長期時(shí)效對(duì)一種新型鎳基合金的組織及持久性能的影響 3(+×500hAC 斷口形貌 ; (b (標(biāo)準(zhǔn)熱處理 +750×500hAC 縱剖面形貌 ;(c +750×2000hAC 斷口形貌 ; (d (標(biāo)準(zhǔn)熱處理 +750×2000hAC 縱剖面形貌Fig 13 750 510MPa stress 2rupture fractographs and micrographs of longitudinal section of the alloy

12、after long 2term aging (a fractograph of sam ple N o 11; (b m orphology of longifudinal section of sam ple N o 11;(c fractograph of sam ple N o 14; (d m orphology of longifudinal section of sam ple N o 14 圖 3a 為合金經(jīng)標(biāo)準(zhǔn)熱處理后 , 再經(jīng) 750 ×500hAC 處理后 ,750 510MPa 下的持久斷口形貌 , 從 中可見 , 韌窩較深 , 撕裂帶較多 , 有明顯的撕裂紋

13、絡(luò) , 從其縱剖面 (圖 3b 可見 , 合金的斷裂為混合型斷裂 , 裂紋的走向既有沿晶擴(kuò)展也有穿晶擴(kuò)展 ,T CP 相析出 不明顯 , 與其有較高的持久強(qiáng)度相對(duì)應(yīng) 。圖 3c 為經(jīng) 標(biāo)準(zhǔn)處理后 , 再經(jīng) 750 ×2000hAC 處理后 , 750 510MPa 下的持久斷口形貌 , 從中可見 , 韌窩較淺 , 沒 有明顯的撕裂紋絡(luò) , 從其縱剖面 (圖 3d 可見 , 合金的 斷裂以穿晶斷裂為主 , 因此合金的強(qiáng)度與塑性主要受 到長期時(shí)效后晶內(nèi) 相長大的影響 , 同時(shí)發(fā)現(xiàn) , 裂紋 萌生于晶界及 T CP 相并向晶內(nèi)擴(kuò)展 。由此使合金的 強(qiáng)度降低并導(dǎo)致塑性的增加 。3 分析與討論

14、高溫持久強(qiáng)度與蠕變激活能關(guān)系 :高溫合金高溫 下的持久強(qiáng)度是合金的重要力學(xué)性能指標(biāo) , 其應(yīng)力 、 溫度及一定應(yīng)力條件下持久時(shí)間的關(guān)系和蠕變性能 規(guī)律是一致的 , 在高溫一定條件下持久斷裂的過程包 括 :位錯(cuò)運(yùn)動(dòng)的聚集 、 裂紋源的形成以及擴(kuò)展達(dá)到臨 界條件 、 持久裂紋迅速擴(kuò)展導(dǎo)致最終斷裂 。 因此高溫 下持久裂紋形成過程也是由熱激活開始 , 而裂紋擴(kuò)展 路徑與合金相及組織有密切關(guān)系 。 對(duì)持久性能而言 , 持久斷裂時(shí)間與變形速率一般呈倒數(shù)關(guān)系 5, 即當(dāng)應(yīng) 力為常數(shù) =k 時(shí) , 則存在 :t=Ae -RT (1 t 2持久斷裂時(shí)間 ; R 2氣體常數(shù) ; Q 2蠕變激活能 ; T 2試驗(yàn)

15、時(shí)間 。lg t -2. 3R=-C (2 其中 C =lg A 。表 3 試驗(yàn)合金長期時(shí)效過程中 750 510MP a 下 持久激活能 Q (kJ molT able 3 750 510MP a stress 2rupture activation energy of the alloy during long 2term agingAging tem perature Aging time h Q (k J m ol 500430. 507501000421. 821500422. 00500420. 198001000408. 041500409. 19500408. 13850100

16、0405. 751500406. 89這樣一定應(yīng)力條件下 log t 與T呈直線關(guān)系 , 其斜率為2. 3R, 即可得出一定應(yīng)力條件下持久應(yīng)變激活85材 料 熱 處 理 學(xué) 報(bào) 第 27卷 能 Q 。根據(jù) G H4586A 合金在 510MPa 750 持久實(shí)驗(yàn)結(jié) 果 , 求出的經(jīng)不同溫度和時(shí)間時(shí)效合金的持久應(yīng)變激 活能見表 3。表 3結(jié)果表明 , 時(shí)效溫度提高可以降低持久過程 的激活能 , 而時(shí)效時(shí)間的延長由 500h 到 1000h , 激活 能降低明顯 , 而 1000h 到 1500h 變化不明顯 。這是因?yàn)樵囼?yàn)溫度范圍內(nèi)隨著 M 23C 6、相和 相的析出 , Cr 、 M o 、

17、W 、 C o 等固溶強(qiáng)化元素由 基體轉(zhuǎn)入到析出相中 , 導(dǎo)致在 基體中的濃度降低 , 低 , 使高溫持久強(qiáng)度降低 729。 溫持久強(qiáng)度的影響與 相尺寸的變化有關(guān) 。4 結(jié)論1 試驗(yàn)合金在 750-800 時(shí)效有片狀 T CP 相析出 , 隨其析出量的增加 , 使合金基體的強(qiáng)度降低 , 合金持久斷裂趨于從沿晶斷裂轉(zhuǎn)為穿晶斷裂 ;2 在 800、 850 ,1000h 處 , ;, 750 510MPa , 。參考文 獻(xiàn)1 ZHAO Shuang 2qun , XIE X i 2shan , Sm ith G aylord 2D , et al. M icrostructural stabili

18、ty and mechanical properties of a new nickel 2based superalloyJ.M aterialsScience and Engineering A ,2003,355(1 :96-105.2 XIE Shi 2shu , PAN X ian 2feng , Y ANG H ong 2cai , et al. E ffects of m icrostructure on fatigue crack growth behavior in Ni 2base supperalloy G H586J.ActaM etallurgica , 1999,

19、12(3 :267-272.3 郭士文 , 張玉鎖 , 楊洪才 , 等 . 鎳基高溫合金長期時(shí)效后 相長大動(dòng)力學(xué) J.東北大學(xué)學(xué)報(bào) (自然科學(xué)版 , 2003, 24(6 :576-579.G UO Shi 2wen , ZHANG Y u 2suo , Y ANG H ong 2cai , et al. K inetic study on the growth of precipitated phase during long time aging in G H4199superalloy J.Journal of N ortheastern Uniersity (Natural Scien

20、ce , 2003, 24(6 :576-579.4 XIE Shi 2shu , W ANG T ie 2li , Y ANG H ong 2cai , et al. E ffects of Z r on m icrostructure and short 2term strength in G H586J.J M ater Sci T echnol , 1999, 15(5 :415-417.5 S ims T , S toloff S , M agel C. Superalloys M.New Y ork John wiley :1987, 259-284.6 Barry M cgurr

21、an , Jhon W M arting. The control of distribution by duplex dispersions of phase in a nickel 2based superalloyJ.Z eitschrift fur M etallkunde ,1981, 72(3 :538-541.7 Nathal M V , Eberb L J. The in fluence of cobalt , tantalum , and tungsten on the elevated tem perature mechanical properties of single

22、 crystal Nickel 2basesuperalloysJ.M etallurgical T ransactions A , 1985, 16(10 :1863-1868.8 Fuchs G E. S olution heat treatment response of a third generation single crystal Ni 2base superalloyJ.M aterial Science and Engineering A , 2001, 300(1 :52-60.9 Ham R K. Ordered Alloys :S tructure and Physic

23、al M etallurgyM.Baton R ouge.LA :Claitors. 1970, 365-369.95第 5期 崔 彤等 :長期時(shí)效對(duì)一種新型鎳基合金的組織及持久性能的影響transmission election microscopy and an images analysis approach. The results show that the addition of Mn and S i obviously restrains the growth of cementite particles in the severely cold 2rolled pearlite

24、 during subsequent annealing , and im proves the distribution evenness of spheroidized cementite particle sizes. The addition of Mn is m ore effective to refine the cementite particles than that of S i. The coarsening kinetics equations of cementite particles for the alloys of Fe 2018C , Fe 2018C 21

25、S i and Fe 2018C 21Mn are d =18614t 01195, d = 9015t 0. 205and d =85. 9t 0. 166in turn.K ey w ords :alloying element ; pearlite ; cementite ; cold rolling ; annealingE ffect of annealing process on microstructure and anical properties of severe plastic deform ation wire T U Y i 2y ou 1, LI U X iang

26、212Lei 2AN Jian 2chun 2(1. Engineering , S outheast University , 210096, China ; 2. Jiangsu Fasten G roup , Jiangyin 214433,China T rans M ater Heat T reat , 2006,27(5 :4345,figs 3,tabs 2,refs 11. Abstract :E ffect of annealing process on microstructure of SWRH72A steel wire under severe plastic def

27、ormation were investigated by TE M and XRD. The XRD analysis shows that severe plastic deformation causes partial of cementite decom position and diss olution of carbon into ferrite up to 0134at %.Cementites form which distribute dispersively in matrix when the annealing tem perature reachs 200-300

28、, resulting in increasing the strength of wire. Annealing tem perature reachs 400 ,the strength of wire decreases sharply ,but the plasticity enhances significantly.K ey w ords :pearlitic steel ; severe plastic deformation ; cementite re 2 diss olution ;annealingI nvestigation on dynamic recrystalli

29、zation of FGH 96powder metallurgy superalloyLI U Jian 2tao 1, ZH ANG Y i 2wen 1, T AO Y u 1, LI U G uo 2quan 2, H U Ben 2fu 2(1. High T em perature Material Institute , Central Iron and S teel Research Institute ,Beijing 100081,China ; 2. School of Material Science and Engineering , University of Sc

30、ience and T echnology Beijing , Beijing 100083,China T rans M ater Heat T reat , 2006,27(5 :4650,figs 8,tabs 0,refs 6. Abstract :Thedynamic recrystallization (DRX behaviour of as 2HIP FG H96P M superalloy at 1070 1170 with strain rate at 5×10-4s -12×10-1s -1was studied by means of is other

31、mal com pression test on a G leeble 21500thermal mechanical simulator. The experiment results show that curves of true stress ( 2true strain ( at higher strain rate ( 2×10-2s -1 are the type of dynamic recrystallization and are the type of dynamic recovery at lower stain rate ( 2×10-3s -1

32、. Although tem perature , strain rate and strain are im portant factors which affect grain refining during hot deformation , grain size during DRX is mainly determined by strain rate to s ome degree. The grain size ( D and Z ener 2H ollm on parameter (Z during DRX process obey the following equation

33、 :ln D =71617- 010134ln Z . By means of w orking hardening rate 2strain curves deduced from the stress 2strain curves ,the steady strain (s is determined ,and als o the diagram of DRX for FG H96P M superalloy is given.K ey w ords :FG H96P M superalloy ; hot deformation ; dynamic recrystallizationPre

34、cipitation of microalloyed carbonitride and its strengthening mech anism in low carbon steels Nb and MoC AO Jian 2chun 1,2, Y ONG Qi 2long 22y ou 2, S UN X in 2jun 2 (1. Engineering , K unming University and 650093, China ; 2. , Central Iron and S teel Research Institute ,China M ater Heat T reat ,

35、2006,27(5 :5155,figs 3,tabs 7,refs 12. Abstract :Thedistribution , m orphology , com position , crystal structure and particle size of microalloyed carbonitride precipitates in hot rolled Nb 2M o steels were examined by XRD , TE M and E DS. The results reveal that the fine and uniformly distributed

36、MC type carbonitrides containing M o and Nb with NaCl type structure precipitate in the steels , in which the atomic ratios of M o to Nb in 01081Nb 20114M o steel and 0117Nb 20112M o steel are 0141and 0122, respectively. Meanwhile , the mass percent of the fine particles (<10nm in the tw o Nb 2M

37、o steels is 5814%and 6611%, respectively , and the corresponding yield strength increments reach to 17913MPa and 25717MPa. The mechanism of the precipitation is discussed.K ey w ords :microalloying carbonitride ; niobium ; m olybdenum ; precipitation ; precipitation strengtheningMicrostructures and

38、high 2temperature properties of a new Ni 2 b ased superalloy after long 2term agingC UI T ong 1, W ANG Ji 2jie 2, W ANG Lei 1, Y ANG H ong 2cai 1, ZH AO G uang 2pu 3(1. C ollege of Materials and Metallurgy , N ortheastern University , Shenyang 110006, China ; 2. Department of Materials Engineering ,

39、 Shenyang Institute of Aeronautical Engineering , Shenyang 110034, China ; 3. Central Iron and S teel Research Institute , Beijing 100081, China T rans M ater Heat T reat , 2006,27(5 :5659,figs 3,tabs 3,refs 9. Abstract :The relationship between high 2tem perature stress 2rupture properties and micr

40、ostructure of a Ni 2base alloy used in spacecrafts was investigated after long 2term aging at tem peratures of 750 , 800 and 850 ,respectively. The microstructure and stress 2rupture fractographs were als o analyzed by means of SE M. The results indicate that T CP (T opologically Close 2Packed phase

41、 , a harm ful phase to Ni 2 base alloy , precipitated during aging at tem peratures from 750 to 800 , and its quantities and sizes increase with the aging time increasing that make the strength of matrix of alloy decrease and the stress 2rupture behavior be changed from grain boundary rupture to gra

42、in interior. 750 510MPa stress 2rupture strength of the alloy aged at tem peratures of 800 and 850 for 1000h was the lowest , respectively because of the changes of phase size. The higher of aging tem perature is , the lower of 750 510MPa stress 2rupture 第 5期 M AI N T OPICS , ABSTRACTS &KEY W OR

43、DS 材 料 熱 處 理 學(xué) 報(bào) 第 27 卷 10Cr9Mo1 VNb steel after high temperature aging 1 2 University , Harbin 150001 , China ; 2. Harbin Boiler Company Ltd , Harbin 150046 , China Abstract : The T rans Mater Heat T reat , 2006 ,27 (5 :6063 ,figs 5 ,tabs 2 ,refs 6. mechanical properties and microstructure 10Cr9Mo1

44、VNb steel aged at high temperature were investigated. The results show that the stability of microstructure of 10Cr9Mo1VNb steel observed for the steel aged at 625 for 10000h compared with that of properties based on the TEM observation and EDS analysis. Key words : 10Cr9Mo1VNb steel ; mechanical pr

45、operties ; microstructure ; M23 C6 phase of aerobic IOB and anaerobic SRB isolated from cooling water system in oil refinery was investigated using bacterial analyses , electrochemical measurement , scanning electron microscopy ( SEM of SRB and IOB , in comparison with those observed in the sterile

46、sterile medium remained virtually unchanged with exposure time , action of sulfate2reducing and iron2oxidizing bacterias 1 1 1 2 pitting corrosion. It is suggested from the present study that SRB and IOB in influencing pitting corrosion of 316L SS is highlighted. the as2received steel. The ultimate

47、tensile strength only decreases that larger amount of M23 C6 and MC carbides precipitated in the steel during aging is the main reason of its excellent high temperature high temperature ageing ; sheng ( 1. Xi an Jiaotong University , Xi an 710049 , China ; PetroChina Company Limited , Lanzhou 730060

48、 , China 2. Research and Technology Center of Lanzhou Oil Refinery Factory , T rans Mater Heat T reat , 2006 ,27 (5 :6469 ,figs 6 ,tabs 2 ,refs 13. and energy dispersive spectrum ( EDS . The results show that the Ecorr , Epit and Erp of 316L SS decrease significantly for the presence medium for the

49、same exposure time interval. Ecorr of 316L SS in the indicating that pitting attack did not occur. However , micrometer2 scale pitting is observed on the 316L SS surface in the combination action of SRB and IOB. The combination action of SRB and IOB demonstrates higher corrosion rates than that in t

50、he sterile medium. The biofilm observed by biology microscope is neither integrity nor compact. The metabolic activity of bacteria under biofilms increases the corrosion damage degree of the passive film , and accelerates the activation energy will be , so that stress2rupture strength of the alloy i

51、s decreased. energy Study on mechanical properties and microstructure 1 ( IOB ; 316L stainless steel ; biofilm passive film ; pitting corrosion Effect of multiple thermomechanical heat treatment at high temperature is excellent and no significant change of strength is about 115 % for the steel after

52、 the aging treatment. It is concluded Corrosion behavior of 316L stainless steel in the combination Abstract :The corrosion behavior of 316L SS in the combination action CHANG Tie2jun , G ONG Zheng2chun , LI Ming2fei , WANG Yu XU Cong2min , ZHANG Yao2heng ,CHENG Guang2xu , ZHU Wen2 Packed phase ; st

53、ress2rupture property ; stress2rupture activation of 1 (1. School of Mechanical and Eletric Engineering , Harbin Engineering Key words :Ni2base alloy ;long2term aging ; TCP ( T opologically Close2 of titanium alloy was studied. The results indicate that the multiple thermomechanical further refined

54、by low2temperature thermomechanical heat treatment. temperature drops slightly. improving mechanical property of titanium alloy. treatment ; microstructure ; mechanical property pressure 2 LI Chun2fu China fluid condition of CO2 ( 35MPa , 160 exited in deep well. The structure and electrochemical be

55、havior of the corrosion scale were period of 48 to 144 hours , the FeCO3 scale gradually changes into a fine compound scale consisted of ( Fe , Ca CO3 , Fe2 CaCO3 and treatment on the microstructure of the near2alpha TA15 titanium alloy heat treatment can markedly refine the microstructure of TA15 alloy , and the mechanical properties of TA15 alloy can be improved. In treatment can refine grains and the microstructure of fine2acicular high temperature are improved in some extent by the multiple thermomechanical heat treatment. At the same time , the creep rupture The multiple thermom