TiAl金属间化合物及其连接技术的研究进展

近年来 ,TiAl金属间化合物由于其密度小、硬度大、耐高温、具有优良的抗氧化能力等独特的性能 ,因此越来越引起广泛的关注并得到了迅猛的发展。根据目前TiAl金属间化合物被认为是在航空、航天飞行器等军事和民用两者都具有广泛应用前景的高温结构材料 ,文中介绍了世界范围内TiAl金属间化合物研究发展现状。TiAl金属间化合物有效的运用必须要有可靠的连接技术 ,因此TiAl金属间化合物的连接问题是其实用化所要面临的问题之一。固态焊接是实现TiAl金属间化合物连接十分有效的方法。文中介绍了TiAl金属间化合物连接技术的发展现状 ,重点评述了TiAl金属间化合物固态焊接的研究状况 ,指出了需要深入研究的问题     

TiAl金属间化合物及其连接技术的研究进展

近年来 ,TiAl金属间化合物由于其密度小、硬度大、耐高温、具有优良的抗氧化能力等独特的性能 ,因此越来越引起广泛的关注并得到了迅猛的发展。根据目前TiAl金属间化合物被认为是在航空、航天飞行器等军事和民用两者都具有广泛应用前景的高温结构材料 ,文中介绍了世界范围内TiAl金属间化合物研究发展现状。TiAl金属间化合物有效的运用必须要有可靠的连接技术 ,因此TiAl金属间化合物的连接问题是其实用化所要面临的问题之一。固态焊接是实现TiAl金属间化合物连接十分有效的方法。文中介绍了TiAl金属间化合物连接技术的发展现状 ,重点评述了TiAl金属间化合物固态焊接的研究状况 ,指出了需要深入研究的问题     

TiAl基金属间化合物的发展

介绍了普通TiAl基金属间化合物的发展过程,特别是北京科技大学开发的高Nb—TiAl金属间化合物的成分-组织-性能-制备关系,Nb对TiAl合金相关系和抗氧化性的影响,Nb的强化机理和工程合金的制备和性能。最后简单总结了TiAl基金属问化合物的发展趋势。     

TiAl金属间化合物与NiCr20TiAl摩擦焊接性分析

采用SN比设计方法优化了TiAl金属间化合物与NiCr20TiAl摩擦焊接的工艺规范，分析了接头组织变化规律，研究了TiAl全属间化合物摩擦焊接成形控制特点。     

轻质γ-TiAl金属间化合物的研究进展

γ-TiAl金属间化合物是一种新型轻质的高温结构材料,是当代航空航天工业、民用工业等领域的优秀候选高温结构材料之一,具有重要的工程化应用潜力。介绍了γ-TiAl基金属间化合物的发展过程,以及成分-组织-性能-制备关系,产业化和应用状况。特别指出,北京科技大学发展的高Nb,TiM金属间化合物为国内外TiAl基金属间化合物发展的重点方向。最后总结了TiAl基金属间化合物的国家需求和发展趋势。     

ZA27合金Ti变质机理电子理论研究

采用分子动力学法建立了熔体ZA27合金模型,并通过计算机模拟获得α相-熔体ZA27界面、α相- TiAl3化合物界面原子集团.用递归法计算了α相、TiAl3化合物的结构能,α相与熔体金属,α相与TiAl3化合物的界面能.计算结果表明：TiAl3化合物的结构能高于α相的结构能,合金凝固时TiAl3化合物先于α相从熔体中析出;α相与TiAl3化合物间的界面能低于α相与熔体金属间的界面能,α相以TiAl3化合物为基体形核比之从熔体金属直接形核增加的界面能少,可减少形核功,因此,TiAl3可成为α相的异质核心,增加α相形核率,细化合金组织.     

高温钛合金及TiAl金属间化合物的精密铸造技术及应用前景

本文对高温钛合金及TiAl金属间化合物的发展趋势进行了概述,介绍了钛合金及TiAl金属间化合物水冷铜坩埚真空感应熔炼(ISM)熔模精密铸造技术的研究现状.最后,介绍了高温钛合金及TiAl金属间化合物在航空航天领域与民用领域中的应用和发展前景.     

飞机用的钛铝化合物

人们正在研究与开发的钛铝金属间化合物包括Ti_3Al、TiAl和Al_3Ti,其有关性能如下: 各种钛铝化合物都比普通的钛合金更抗高温氧化,密度更低,抗蠕变能力更强,弹性模量更大。但是如同其它金属间化合物一样,钛铝在室温下也是极脆的。事实表明,添加β稳     

原位自生TiAl3增强Al基复合材料的组织结构及形成机理研究

采用冷喷涂技术沉积Ti-80Al（wt.%）复合涂层,通过热处理获得了原位自生TiAl3金属间化合物颗粒增强Al基复合材料涂层。采用SEM、EDS和XRD等分析了冷喷涂Ti/Al复合涂层在不同热处理温度下的组织结构演变规律及Ti、Al粒子间原位扩散反应过程,并对TiAl3金属间化合物的形成机理进行了探讨。结果表明,冷喷涂Ti/Al复合涂层组织致密,其相结构与喷涂粉末完全相同,450℃热处理后涂层局部区域发生Ti、Al间的固态扩散反应,并在Ti、Al粒子界面原位形成TiAl3金属间化合物,随着热处理温度升高,TiAl3金属间化合物的含量显著增加,600℃热处理后,Ti/Al复合涂层中的Ti粒子全部转变为TiAl3金属间化合物,获得原位自生TiAl3颗粒增强的Al基复合材料.     

TiAl合金微弧氧化陶瓷层研究

TiAl金属间化合物具有高的比强度和比刚度，是制造新一代先进航空航天器装置最理想的候选结构材料之一。然而．金属间化合物所面临的主要障碍是其室温塑性低和在高温腐蚀环境中易氧化等问题。微弧氧化是一种在有色金属表面原位生长陶瓷层的新技术。不同     

Microstructure and strength of the TiAl/40Cr joint diffusion-bonded with Ti-V-Cu filler metal

In this study,intermetallic TiAl and steel 40Cr diffusion bonded successfully by using a composite barrien layer Ti/V/Cu,In this case,a diphase Ti3Al TiAl layer and a Ti solid solution which enhance the strength of the joint are obtained at the TiAl/Ti interface.The interface of TiAl/Ti/V/Cu/40Cr was free from intermetallic compounds and other brittle phases,and the strength of the joint was as high as 420MPa,very close to that of the TiAl base.This method gives a reliable bonding of intermetallic TiAl and steel 40Cr.     

TiAl合金激光气体合金化

本文利用激光气体合金技术对ＴｉＡｌ合金进行表面改性，制得了以ＴｉＮ为增强相的新型快速凝固“原位”耐磨复合材料表面改性层，激光表面改性层显微组织受激光处理工艺参数的控制，试验结果表明，激光气体合化是一种提高ＴｉＡｌ合金耐磨性的表面改性新技术。     

EFFECT OF CoCrAl COATING ON OXIDATION RESISTANCE OF INTERMETALLIC COMPOUND TiA1

Effect of a sputtered Co-30Cr-5Al microcrystalline coating on oxidation resistance ofintermetallic compound TiAl and oxidation behavior of the bare TiAl were investigatedat 900—1000℃ in static air.The oxidation kinetics for the TiAl alloy seems toapproximately follow a linear rate law.Poor oxidation resistance of TiAl is due to theformation of the mixed Al_2O_3+TiO_2 scale which is loosely packed and easily spalledoff.but not of dense and adherent pure Al_2O_3.A sputtered Co-30Cr-5Al coating,30μm thickness,can remarkably improve the oxidation resistance of TiAl owing to theformation of adherent Al_2O_3 protective scale.However,many Kirkendall voids wereformed between coating and substrate.     

Ni-Al系、Fe-Al系和Ti_3Al金属间化合物研究进展

简要介绍了金属间化合物的熔炼与铸造工艺。论述了Ni Al系 (包括NiAl和Ni3 Al)、Fe Al系 (包括Fe3 Al和FeAl)及Ti3 Al基金属间化合物高温结构材料的研究现状和发展动态 ,分析了上述合金存在的问题及解决办法 ,介绍了它们在不同领域的潜在应用。     

TiAl/Ti/V/Cu/40Cr钢扩散连接界面组织结构对接头强度的影响

研究了TiAl/Ti/V/Cu/40Cr钢的扩散连接，结果显示：在TiAl/Ti界面处形成了对接头强度有利的Ti3Al TiAl双相层及Ti固溶体层，而Ti/V/Cu/40Cr界面处未出现金属间化合物及其它脆性相，接头最高拉伸强度可达420MPa，接近TiAl母材。     

Environmental corrosion resistance of porous TiAl intermetallic compounds

Porous TiAl intermetallic compound, as a novel substitute for current inorganic porous material, offsets the shortages of both ceramics and metals. The environmental corrosion resistance of porous TiAl intermetallic compound was investigated. The kinetic equation for the cyclic oxidation of porous TiAl alloy at 600 ℃ is determined to be Δm2=1.08×10-5t. After total oxidation of 140 h, porous TiAl intermetallic compound shows more stability of pore structure and the mass gain of TiAl alloy is 0.042 g/m2, which is only 10.6% that of porous 316L stainless steel. The kinetic equation for the cyclic corrosion behavior of porous TiAl alloy in hydrochloric acid with pH=2 at 90 ℃ is determined to be Δm2=5.41×10-5t-2.08×10-4. After 50 h exposure, the mass loss of TiAl alloy is 0.049 g/m2, which is only 14.8% and 5.57% that of porous Ti and stainless steel, respectively. The kinetic equation in hydrochloric acid with pH=3 is determined to be Δm2=2.63×10-6t-3.72×10-6.     

DOUBLE GLOW PLASMA SURFACE ALLOYING OF Ti6Al4V AND TiAl

In order to improve the wear resistance of titanium alloy Ti6Al4 V and high temper-ature oxidation resistance of intermetallic compound TiAl, the Double Glow PlasmaSurface Alloying Technique (DG technique) was applied to modify the surface proper-ties ofthese materials. Mo, Nb, Cr, Ni were diffused into the substrate materials toform alloyed layers with different properties. This paper shows the microstructures,microhardnesses, distributions of the alloy elements of the alloyed layers. Wear andhigh temperature oxidation tests were carried out. The test results indicate that thewear resistance of Ti6Al4 V and the high temperature oxidation resistance of TiAl wereimproved significantly.     

The fatigue resistance of TiAl-based alloys

TiAl-based alloys are a class of intermetallic alloys that show potential as a high-temperature structural material. Many applications considered for TiAl-based alloys require certain damage-tolerance characteristics. In this article, the fatigue resistance of two-phase TiAl alloys is reviewed to assess the current understanding of the fatiguedamage processes in this class of emerging materials. Salient features of fatigue-crack growth and stress-life curves are summarized to identify the challenges these fatigue characteristics present in the life assessment of TiAl components.     

TiAl合金与GH3039高温合金的摩擦焊接

对TiAl合金与GH3039高温合金异种材料进行了摩擦焊接工艺试验. 基于接头的拉伸性能,初步优化了焊接工艺参数. 采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对焊接接头组织、焊合区成分变化及接头连接机理进行了分析. 结果表明,TiAl合金与GH3039高温合金两种异种材料摩擦焊接具有可行性,在摩擦焊接过程中热力耦合的作用下,GH3039侧热力影响区塑性变形较大,TiAl合金侧热力影响区变形较小;TiAl合金与GH3039高温合金摩擦焊接连接界面两侧的合金元素发生了扩散,形成了复杂的层状金属间化合物组织结构;断于TiAl合金母材的焊接接头断口属于典型的脆性断口.     

Effect of a sputtered TiAlCr coating on the oxidation resistance of TiAl intermetallic compound

The effect of a sputtered TiAlCr coating on the oxidation resistance of TiAl intermetallic compound was investigated in static air. The bare TiAl alloy exhibited poor isothermal and cyclic-oxidation resistance at 800–1000°C due to the formation of TiO₂-base scales which tend to spall during cooling. A sputtered Ti-50Al-10Cr coating remarkably improved the oxidation resistance of TiAl, due to the formation of an adherent Al₂O₃ scale at 800–1000°C. After long-term oxidation (at 900°C for 1000 hr), TiAlCr coating still provided excellent protection for the TiAl alloy. Minor interdiffusion occurred due to the inward diffusion of Cr, while no Kirkendall voids were found at the coating/ substrate interface. In contrast, NiCrAlY and CoCrAlY coatings reacted extensively with the TiAl alloys. Moreover, the TiAlCr coating alloy is based on -TiAl and TiAlCr Laves phases, which may offer improved mechanical properties. The TiAlCr coating exhibited a better combination of oxidation resistance and substrate compatibility than conventional aluminide and MCrAlY coatings.