發(fā)布時間：2018-06-08 11:34

  本文選題：Nb-Ti-Si-Cr基超高溫合金 + 硅化物滲層�。� 參考：《西北工業(yè)大學(xué)》2016年博士論文

【摘要】：Nb-Si基多元超高溫合金由于具有熔點高、密度低、高溫強度和室溫斷裂韌性好等一系列優(yōu)點而具有巨大的應(yīng)用潛力。但該合金較差的高溫抗氧化性能嚴(yán)重制約了其實際應(yīng)用。多元合金化雖然能夠有效提高該合金的高溫抗氧化性能,但過量添加合金化元素有時會降低合金的綜合性能如高溫強度和熔點。與合金化不同,表面涂層在改善合金抗氧化性能的同時對合金自身力學(xué)性能的影響較小。因此,在合金化的基礎(chǔ)上制備表面涂層以提供高溫有氧環(huán)境下的保護,是Nb-Si基多元超高溫合金取得實際應(yīng)用的有效手段。本文依據(jù)上述思路,采用Si-Zr-Y擴散共滲和磁控濺射Zr膜+Si-Y擴散共滲兩種方法,在新型Nb-Ti-Si-Cr基多元超高溫合金表面分別制備了Si-Zr-Y共滲層和ZrSi_2-NbSi_2復(fù)合滲層。采用XRD、SEM和EDS等測試手段分析了滲層的相組成、微觀形貌和成分分布。同時,本文針對所制備滲層的特點,研究了Si-Zr-Y共滲層的高溫抗氧化性能、摩擦磨損及固體粒子沖蝕性能和ZrSi_2-NbSi_2復(fù)合滲層的高溫抗氧化性能,并對其高溫抗氧化機理、摩擦磨損和固體粒子沖蝕機制進行了討論,主要結(jié)果如下:(1)采用擴散共滲方法在Nb-Ti-Si-Cr基多元超高溫合金表面制備了Si-Zr-Y共滲層。揭示了催化劑種類(NaF,NH4F,NH4Cl,NaBr和NaCl)和含量(1~8wt.%)、共滲溫度(1100~1350℃)、滲劑中Zr粉含量(5~15wt.%)以及共滲時間(0~12h)對共滲層組織的影響規(guī)律。采用不同種類催化劑經(jīng)1250℃保溫8h所制備的Si-Zr-Y共滲層由外至內(nèi)均由(Nb,X)Si2(X代表Ti,Cr,Zr和Hf)外層、(Ti,Nb)5Si4中間層和富Al,Y的(Nb,X)5Si3內(nèi)層組成。其中,采用NaF為催化劑時制備的共滲層較厚且組織致密,共滲層內(nèi)Zr和Y的含量也較高。滲劑中的NaF含量不會明顯改變共滲層的組織結(jié)構(gòu),但當(dāng)NaF的含量由1wt.%增加到5wt.%時,共滲層的厚度逐漸增加且致密性得到改善,而進一步增加NaF含量至8wt.%時,共滲層的厚度反而有所降低。共滲溫度對滲層的組織結(jié)構(gòu)和生長速率均有顯著影響:1150和1200℃保溫8h所制備的共滲層與1250℃保溫8h所制備的共滲層具有相似結(jié)構(gòu),但1300和1350℃保溫8h所制備的共滲層中出現(xiàn)了疏松多孔的(Ti,Nb)5Si4最外層;同時,共滲層的厚度及滲層內(nèi)Zr和Y元素的含量均隨共滲溫度的升高而增加。增加滲劑中Zr粉含量會相應(yīng)地導(dǎo)致滲層內(nèi)Zr含量的增加,但會明顯抑制共滲層的生長速率,同時,滲劑內(nèi)Zr粉含量過高(15wt.%)還會導(dǎo)致共滲層表面出現(xiàn)富Zr的(Ti,Nb)5(Si,Al)4最外層。共滲層的厚度隨共滲時間的延長呈拋物線規(guī)律增加,表明共滲層的形成由擴散控制,但共滲時間的延長不會明顯改變共滲層的組織結(jié)構(gòu)。(2)選取滲劑組分為10Si-10Zr-3Y2O3-5NaF-72Al2O3(wt.%),經(jīng)1250℃保溫8h所制備的共滲層進行1250℃恒溫氧化、室溫及800℃摩擦磨損及固體粒子沖蝕實驗。結(jié)果表明,所制備的Si-Zr-Y共滲層具有優(yōu)異高溫抗氧化性能,其在1250℃時的恒溫氧化速率常數(shù)較基體合金低約3個數(shù)量級。氧化后所形成的氧化膜主要由較薄的TiO2外層和致密的SiO2內(nèi)層組成,該氧化膜能夠在1250℃的空氣中保護基體合金長達200h。但經(jīng)200h氧化后的氧化膜在局部出現(xiàn)開裂和剝落。Si-Zr-Y共滲層的硬度顯著高于Nb-Ti-Si-Cr基體合金。在相同的摩擦載荷下,Si-Zr-Y共滲層無論在室溫還是800℃時的摩擦磨損抗力均優(yōu)于基體合金,原因為在共滲層試樣的磨損表面形成了由SiO2組成的氧化產(chǎn)物,可對磨損面起到有效保護。與基體合金相比,Si-Zr-Y共滲層在30°小攻角沖蝕狀態(tài)下具有更高的耐沖蝕抗力,但在90°大攻角沖蝕狀態(tài)下的耐沖蝕抗力較低。(3)采用先在合金表面磁控濺射Zr膜,然后Si-Y擴散共滲的方法,在Nb-Ti-Si-Cr基多元超高溫合金表面成功制備了ZrSi_2-NbSi_2復(fù)合滲層。揭示了沉積Zr膜的厚度(2~10μm)及Si-Y共滲溫度(1150~1350℃)對滲層組織的影響規(guī)律。發(fā)現(xiàn)不同Zr膜厚度和Si-Y共滲溫度所制備的滲層具有相似的結(jié)構(gòu),均主要由ZrSi_2外層,(Nb,X)Si2(X代表Ti,Cr,Zr和Hf)中間層和(Ti,Nb)5Si4內(nèi)層組成,共滲層的厚度隨著共滲溫度的升高顯著增加,過高的Si-Y共滲溫度(1350℃)還會導(dǎo)致共滲層中各層界面處產(chǎn)生裂紋。選取Zr膜厚度為10μm,再經(jīng)1250℃/4h Si-Y共滲所制備的滲層進行1250℃恒溫氧化實驗。結(jié)果表明,ZrSi_2-NbSi_2復(fù)合滲層具有較好的高溫抗氧化性能。氧化后在滲層表面形成了由SiO2,ZrSiO4,ZrO2,Al2O3,TiO2和Cr2O3混合組成的致密氧化膜,該氧化膜能夠在1250℃的空氣中保護基體合金100h以上。氧化膜的形成過程包括ZrSi_2外層的氧化和保護性內(nèi)氧化膜的生長兩個階段。其中,ZrSi_2外層的氧化較為迅速,此時氧化膜的生長主要由O的內(nèi)擴散控制,隨著保護性內(nèi)氧化膜的形成和生長,氧化膜的生長逐漸由O的內(nèi)擴散占優(yōu)轉(zhuǎn)變?yōu)镾i,Ti,Cr和Al的外擴散占優(yōu)。
[Abstract]:Nb-Si based superalloy has great potential for application because of its high melting point, low density, high temperature strength and good fracture toughness at room temperature. However, the poor high temperature oxidation resistance of the alloy seriously restricts its practical application. The addition of alloying elements can sometimes reduce the comprehensive properties of the alloy, such as the high temperature strength and melting point. Unlike alloying, the surface coating has little effect on the alloy's mechanical properties while improving the antioxidant properties of the alloy. Therefore, the surface coating is prepared on the basis of alloying to provide protection under the high temperature and aerobic environment, which is the Nb-Si base. Based on the above thought, the Si-Zr-Y co impermeable layer and ZrSi_2-NbSi_2 composite layer were prepared on the surface of the new Nb-Ti-Si-Cr based multivariable superalloy by using the two methods of Si-Zr-Y diffusion co permeation and magnetron sputtering Zr film +Si-Y diffusion co permeation. The methods of XRD, SEM and EDS were used. The phase composition, microstructure and composition distribution of the impermeable layer were analyzed. At the same time, the high temperature oxidation resistance, friction and wear, solid particle erosion and high temperature oxidation resistance of the Si-Zr-Y composite layer were studied, and the high-temperature oxidation resistance mechanism, friction and wear and solid particles were also studied. The main results are discussed. The main results are as follows: (1) Si-Zr-Y co permeation layer was prepared on the surface of Nb-Ti-Si-Cr based multicomponent superalloy by diffusion diffusion method. The types of catalysts (NaF, NH4F, NH4Cl, NaBr and NaCl) and content (1~8wt.%), CO infiltration temperature (1100~1350), Zr powder content (5~15wt.%) and co infiltration time (0~12h) in the permeation agent (0~12h) were revealed. The effect of the co permeable layer on the microstructure of the co permeable layer. The Si-Zr-Y Co layer prepared by different kinds of catalysts at 1250 C for 8h is made up of the outer layer (Nb, X) Si2 (X representing Ti, Cr, Zr and Hf), and (Ti, Nb) intermediate layer and the rich inner layer. The content of Zr and Y in the layer is also higher. The NaF content in the permeable agent does not obviously change the structure of the co permeable layer, but when the content of NaF increases from 1wt.% to 5wt.%, the thickness of the co permeable layer is gradually increased and the densification is improved, while the thickness of the co permeable layer decreases when the NaF content is increased to 8wt.%. The fabric structure and growth rate have significant influence: the co permeable layer prepared by 8h at 1150 and 1200 C is similar to the co permeable layer prepared at 1250 C for 8h, but the porous (Ti, Nb) 5Si4 layer appears in the co permeable layer prepared at 1300 and 1350 C, and the thickness of the co permeable layer and the content of the Zr and Y elements in the infiltration layer are all in the same time. With the increase of CO permeation temperature, the content of Zr powder in the permeating agent will lead to the increase of Zr content in the permeable layer, but it can obviously inhibit the growth rate of the co permeable layer. At the same time, the high content of Zr powder (15wt.%) in the permeating agent will lead to the appearance of Zr (Ti, Nb) 5 (Si, Al) 4 in the surface of the co permeable layer. The thickness of the co permeable layer is prolonged with the prolongation of the co permeation time. The increase of parabolic law shows that the formation of the co permeable layer is controlled by diffusion, but the prolongation of the co permeation time will not change the structure of the co permeable layer. (2) the permeation agent is selected as 10Si-10Zr-3Y2O3-5NaF-72Al2O3 (wt.%), the co permeable layer prepared by 8h at 1250 C is oxidized at 1250 C, and the friction and wear of the solid particles and the solid particles at room temperature and 800. The results show that the prepared Si-Zr-Y co permeable layer has excellent high temperature oxidation resistance, and the constant temperature oxidation rate constant at 1250 C is about 3 orders lower than that of the matrix alloy. The oxide film formed mainly by the thinner TiO2 outer layer and the dense SiO2 inner layer, and the oxide film can be protected in the air of 1250 degrees C. The hardness of the matrix alloy as long as 200h. but the oxidation film after 200H oxidation is significantly higher than that of the Nb-Ti-Si-Cr matrix alloy. The friction and wear resistance of the Si-Zr-Y co permeable layer at room temperature or 800 C is better than that of the base alloy under the same friction load. The reason is the wear of the specimen in the co permeable layer. The surface formed an oxidation product composed of SiO2, which can effectively protect the wear surface. Compared with the matrix alloy, the Si-Zr-Y co permeable layer has a higher erosion resistance at 30 degrees of attack angle and erosion, but the resistance to erosion is lower at the 90 degree of attack angle. (3) the magnetron sputtering Zr film on the alloy surface and then the Si-Y diffusion are used. The ZrSi_2-NbSi_2 composite layer was successfully prepared on the surface of Nb-Ti-Si-Cr based multivariable superalloy. The influence of the thickness of the Zr film (2~10 mu m) and the Si-Y co infiltration temperature (1150~1350 C) on the layer tissue was revealed. It was found that the layers of different Zr film thickness and Si-Y co permeation temperature have similar structure, all of which are mainly Zr. The Si_2 outer layer, (Nb, X) Si2 (X represents Ti, Cr, Zr and Hf) in the middle layer and (Ti, Nb) 5Si4 inner layer, the thickness of the co permeable layer increases significantly with the increase of the co permeation temperature. The exorbitant permeation temperature (1350 degrees C) will lead to the crack in the interface of the layers of the co permeable layer. The thickness of the membrane is selected and then the layer prepared by the infiltration of 1250 degrees Celsius is carried out. The experimental results show that the ZrSi_2-NbSi_2 composite layer has good oxidation resistance at high temperature. After oxidation, a dense oxide film composed of SiO2, ZrSiO4, ZrO2, Al2O3, TiO2 and Cr2O3 is formed on the surface of the permeable layer. The oxide film can protect the matrix alloy 100h above the base alloy in the air of 1250 C. The formation process of the oxide film is wrapped. Including the two stages of the growth of the oxide and protective inner oxide film on the outer layer of ZrSi_2, the oxidation of the outer layer of the ZrSi_2 is more rapid. At this time, the growth of the oxide film is mainly controlled by the internal diffusion of O. With the formation and growth of the protective inner oxide film, the growth of the oxide film is gradually transformed from the internal diffusion of O to Si, and the external diffusion of Ti, Cr and Al is superior.
【學(xué)位授予單位】：西北工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TG174.4

【相似文獻】

相關(guān)期刊論文 前10條

1 徐焱慧;王黎;;鋼硼鋁稀土共滲層的組織與性能的研究[J];磚瓦;2006年04期

2 張振信,吉澤升;稀土對硼鋁共滲過程及滲層性能的影響[J];稀土;1990年01期

3 吉澤升,張振信;稀土對45鋼硼鋁共滲滲層生長初期的影響[J];稀土;1992年06期

4 黃濟元;鄒敢鋒;袁叔貴;肖繼闖;;粉末鈦鋁共滲的研究[J];金屬熱處理;1993年07期

5 楊川，，吳大興，高國慶;超厚硼鋁共滲層的研究[J];金屬熱處理學(xué)報;1995年03期

6 沈蜀西,白玲;4Cr5MoSiV1鋼硼鋁稀土共滲層的組織與性能[J];熱加工工藝;2004年02期

7 蔡航偉;高原;馬志康;王成磊;袁琳;張維;李冰;;鎢鉬釔等離子共滲工藝及滲層組織的研究[J];表面技術(shù);2012年02期

8 張振信;;硼釩鉻共滲層組織結(jié)構(gòu)的研究[J];哈爾濱科學(xué)技術(shù)大學(xué)科學(xué)報告會論文摘要匯編;1985年S1期

9 劉永(火斤);;涂料硼鋯共滲工藝對共滲層組織和脆性的影響[J];金屬科學(xué)與工藝;1990年03期

10 尹付成，洪振聲，金義華;稀土硼鉻共滲工藝及滲層性能的研究[J];熱加工工藝;1996年02期

相關(guān)會議論文 前10條

1 樓白楊;方可軍;李樂國;;鉻鈦共滲及滲層耐磨性分析[A];第六屆全國表面工程學(xué)術(shù)會議暨首屆青年表面工程學(xué)術(shù)論壇論文集[C];2006年

2 樓白楊;方可軍;李樂國;;鉻鈦共滲及滲層耐磨性分析[A];第六屆全國表面工程學(xué)術(shù)會議論文集[C];2006年

3 鄭維能;李成明;;離子鎢鉬共滲的組織分類[A];第十一次全國電子顯微學(xué)會議論文集[C];2000年

4 韋習(xí)成;趙源;;釩氮硫共滲層在含磨料潤滑油中的磨損特性[A];第一屆全國青年摩擦學(xué)學(xué)術(shù)會議論文集[C];1991年

5 吳曉春;張雙科;閔永安;許珞萍;;Cr12MoV鋼等離子S、N、C復(fù)合滲層組織與性能的探討[A];第四屆全國表面工程學(xué)術(shù)交流大會論文集[C];2001年

6 孫躍;馬欣新;徐淑艷;王鵬;;軸承鋼等離子體基升溫注滲層耐磨性研究[A];第七屆全國摩擦學(xué)大會論文集（二）[C];2002年

7 陳躍;上官寶;鐵喜順;杜三明;高新陽;;鎢鉻鑄滲層顯微組織及干滑動磨損特性研究[A];第八屆21�。ㄊ�、自治區(qū)）4市鑄造學(xué)術(shù)年會論文集[C];2006年

8 熊光耀;何柏林;周澤杰;;稀土La對5CrMnMo鋼QPQ滲層組織和性能的影響[A];第七屆全國表面工程學(xué)術(shù)會議暨第二屆表面工程青年學(xué)術(shù)論壇論文集（二）[C];2008年

9 陳飛;周海;呂俊霞;楊英歌;丁莉;任蕾;;25CrNiMo鋼N-C-O多元氣體共滲性能研究[A];第六屆全國表面工程學(xué)術(shù)會議暨首屆青年表面工程學(xué)術(shù)論壇論文集[C];2006年

10 陳飛;周海;潘俊德;;鈦合金表面輝光等離子滲鉭的研究[A];2010全國機械裝備先進制造技術(shù)(廣州)高峰論壇論文匯編[C];2010年

相關(guān)博士學(xué)位論文 前6條

1 李軒;Nb-Ti-Si-Cr基合金表面含Zr和Y的硅化物滲層的組織及性能[D];西北工業(yè)大學(xué);2016年

2 孫先明;鑄鋼表面鎳基滲層的負(fù)壓鑄滲工藝及其摩擦學(xué)性能研究[D];機械科學(xué)研究總院;2011年

3 楊貴榮;銅合金表面鑄滲工藝及滲層性能的研究[D];蘭州理工大學(xué);2006年

4 張平;Nb-Si基合金Si-Al-Y擴散滲層的組織及抗氧化性能[D];西北工業(yè)大學(xué);2014年

5 吳業(yè)瓊;納米晶化18Ni合金稀土共滲層晶粒組織特征和生成相性質(zhì)[D];哈爾濱工業(yè)大學(xué);2011年

6 安亮;Fe_3Si基過渡金屬硅化物滲層及納米復(fù)合粉體的制備與表征[D];蘭州理工大學(xué);2011年

相關(guān)碩士學(xué)位論文 前10條

1 李兆祥;QPQ工藝參數(shù)對SAF2906雙相不銹鋼滲層組織與性能的影響[D];福州大學(xué);2014年

2 張莉;粉煤灰活性劑及在共滲層氬弧重熔中應(yīng)用的研究[D];遼寧工程技術(shù)大學(xué);2014年

3 王義偉;高鋁粉煤灰活性劑及B-C-S共滲層氬弧重熔技術(shù)研究[D];遼寧工程技術(shù)大學(xué);2014年

4 王f ;TA15合金表面Cr-Si復(fù)合滲層的制備及摩擦行為研究[D];南京航空航天大學(xué);2016年

5 張巨銀;鑄鋼表面滲層摩擦性能的研究[D];蘭州理工大學(xué);2010年

6 周游;鑄鋼表面鎳基陶瓷顆粒復(fù)合功能滲層制備與性能研究[D];蘭州理工大學(xué);2011年

7 宋文明;銅合金表面復(fù)合滲層的組織與性能研究[D];蘭州理工大學(xué);2007年

8 李合非;硼鉻稀土共滲技術(shù)應(yīng)用基礎(chǔ)研究[D];山東農(nóng)業(yè)大學(xué);2002年

9 單朝軍;H13鋼RE-N-C-V-Nb共滲滲層動力學(xué)及熱穩(wěn)定性研究[D];廣西大學(xué);2012年

10 劉建局;純銅鋁鐵共滲的實驗研究[D];上海交通大學(xué);2008年

本文編號：1995652