Ti-2Al-2．5Zr钛合金丝材的普通退火工艺

研究了退火温度对Ti-2Al-2.5Zr钛合金丝材力学性能、显微组织的影响规律,并分析了该合金丝材退火后的织构.结果表明,在相变点之下,合金力学性能、显微组织只与再结晶有关;经(700～750)℃×1h·AC的真空退火,可获得均匀细小的等轴组织,强度、塑性达到最佳匹配.在相变点之上,获得锯齿状的粗大晶粒,强度较高,而塑性较差.退火后可获得两种织构,一种为在相变点之下,经完全再结品退火可获得2,-1,-1,0丝织构;另一种为在相变点之上获得,该织构除了具有前一种丝织构外,还具有相对较弱的2,-1,-1,3丝织构.     

热处理工艺对Ti-3Al-6Mo-2Fe-2Zr合金组织和性能的影响

采用OM、SEM和XRD等方法研究了固溶时效热处理对近β型钛合金(Ti-3Al-6Mo-2Fe-Zr)显微组织、力学性能及耐腐蚀性能的影响。结果表明,随着固溶温度的升高,初生α相的含量逐渐降低,经930 ℃固溶处理后,合金为单一β相。固溶温度在830 ℃以下时,随着固溶温度的升高,初生α相逐渐转变为β相,第二相强化作用减弱,合金强度逐渐降低,塑性逐渐提高,断裂方式为微孔聚集型;固溶温度在830 ℃以上时,随着固溶温度的升高,β相晶粒逐渐粗化,合金强度降低,塑性下降,断裂方式由微孔聚集型断裂向解理断裂转变。随着固溶温度从780 ℃升高至930 ℃,初生α相的含量降低,β/α相界逐渐减少,耐腐蚀性能提升。经780 ℃固溶1 h(水冷),500 ℃ 时效6 h(随炉冷却)处理后,细小针状的次生α相于亚稳β相中沉淀析出,合金强度显著提高,但塑性下降。     

低温Ti-5Al-2．5SnELI的研究现状及应用

低温Ti-5Al-2.5SnELI的应用主要集中在航空航天及军事工业中,民用的较少.目前国内外对该合金锻态、轧制板材研究的较多,而对该合金常温下铸态组织与性能研究的较少,低温性能研究的更少,缺少大量的数据积累.因而限制了该合金在铸件产品中的应用.今后还要对该合金常温、低温铸态组织性能进行研究,完善并予以推广.     

Ti-22Al-26Nb-1Zr 合金在长期时效过程中的组织稳定性

研究正交结构Ti?22Al?26Nb?1Zr合金片层组织在长期时效过程中B2相的分解、O相板条的球化等显微组织演变规律。结果表明：合金加热到B2单相区炉冷后可以获得板条组织,在(O+B2)相区700°C时效100 h以内显微组织无明显变化。但在长时时效过程中板条组织发生明显粗化。在700°C长期时效800 h时,B2相极不稳定,会在时效初期短时间内迅速发生分解。随着时效时间的延长,块状和少量板条状O相在晶界和O/BCC相界处析出并以球状形式长大。此外,在时效时间超过100 h后,会有明显的树枝状O相板条组织形成。     

热力因素对合金元素在Ti-24Al-15Nb-1．5Mo／TC4焊接界面上扩散规律的影响

研究了2种状态的金属间化合物基合金Ti-24Al-15Nb-1．5Mo与TC4钛合金毛坯经真空电子束焊接后，锻造温度、热处理制度、变形量等热力因素以及它们的交互作用对合金元素Al，Nb，V在焊接界面上扩散规律的影响。研究发现：增加变形和提高热处理温度，可以增大原子迁移的动能，有利于提高合金元素的扩散速度，均匀焊缝显微硬度：加大变形量，有利于提高品格畸变能并细化晶粒、改变相的形态、减小相的尺寸，缩短合金元素的扩散路程。Nb在重新凝固区Ti-24Al-15Nb-1．5Mo一侧浓度高于合金的名义成分是由于在焊缝区α2→α变化时，Nb从DO19结构点阵中扩散出来，填补Al，Mo扩散后的空位，造成局部堆积所致。变形后热处理规范的不同，导致焊缝区的显微硬度不同，这与热处理过程中显微组织变化有关。     

Ti-6Al-2C合金中片状TiC的形成机制

通过适当的高温热处理工艺 ,可改变TiCp Ti复合材料中枝晶状TiC的形态和尺寸 ,不同的热处理工艺 ,使枝晶TiC变成不同的形态。Ti 6Al 2C(w ,% )合金在 1 2 0 0℃保温 1 0 8ks可使枝晶状TiC粒化 ,但 1 1 0 0℃保温 2 1 6ks时得到平行分布的片状TiC。从理论上初步探讨了片状TiC的形成机制 ,认为TiC可在α Ti(0 0 0 1 )基面上 ,由Shockley位错运动形成的层错区直接生核。从动力学分析TiC沿 [0 0 0 1 ] α Ti方向生长时碳原子需长程扩散 ,而沿α Ti的 [1 1 2 0 ]方向生长时扩散距离很短 ,因此极短的生长时间内 ,TiC只能沿 [1 1 2 0 ] α Ti方向快速生长成片状     

热处理工艺对Ti-45Al-7Nb-0.15B-0.4W显微组织的影响

用电子探针对Ti-45Al-7Nb-0.15B-0.4W的铸态和经过热处理之后的显微组织进行了观察和分析,并分析了热处理工艺对Ti-45Al-7Nb-0.15B-0.4W显微组织的影响.结果发现:Ti-45Al-7Nb-0.15B-0.4W的铸态组织经过热等静压和均匀化处理后,其晶团尺寸减小,层片组织更为完整;Ti-45Al-7Nb-0.15B-0.4W合金的α相转变温度为(1 290±5)℃;Ti-45Al-7Nb-0.15B-0.4W合金在超过1 295℃的温度进行热处理时,其显微组织由近层片组织转变为全层片组织.经过热等静压和均匀化处理后Ti-45Al-7Nb-0.15B-0.4W合金的基本形貌为初生γ相 层片状晶团,有β相析出,其形貌为针状、点状、颗粒状.     

Ti-22Al-24Nb-1Mo O相合金箔材的加工与性能

介绍了一种采用b相区开坯、α2+B2相区热轧、利用四辊可逆冷轧机冷轧Ti-22Al-24Nb-1Mo O相合金0.1 mm厚箔材的工艺过程.研究轧后退火和固溶处理对合金箔材组织和拉伸性能的影响.结果表明:退火后合金组织由等轴O相+B2相组成,其中O相(体积分数)约50%;固溶后合金组织由少量等轴O/α2相+B2相组成;经两种热处理工艺处理后,合金均能获得良好的室温拉伸性能.     

干糊延伸率的分析及及其影响因素的探讨

详细介绍了干糊延伸率的分析方法，其测量方法比较简单，计算结果直观可信，是生产过程质量控制监督的重要手段之一。对于一定的原料及生产工艺条件，干糊处伸率值有一个较佳的范围。在实际生产过程中，混捏温度的高低及混捏时间的长短、沥青配比的大小、骨科配比的改变、焦炭水银气孔量的变化等，都将直接影响干糊延伸率的变化，最终将影响干糊的质量，因此，严格生产工艺条件，及时掌握原料的质量变化，用准确的延伸率数据指导，控     

Ti-45Al-5Nb(-0.3Y)合金的连续冷却相变规律

冷却速度对Ti-45Al-5Nb和Ti-45Al-5Nb-0.3Y合金连续冷却相变有较大的影响.炉冷形成全层片组织,空冷下层片形成被α→γm块状反应抑制,油冷形成了极细小的层片组织,水冷主要发生了α→α2有序化转变.空冷导致了羽毛状组织消失和α2相的增加,水冷导致α2晶界的细小层片晶团尺寸较小、数量较多.Y添加对Ti-45Al-5Nb合金连续冷却相变有较小的影响.     

Study of δ-hydrides in Ti-2Al-2.5Zr and Ti-4Al-2V alloys

The α alloy Ti-2Al-2.5Zr and near α alloy Ti-4Al-2V were hydrogenated to various levels. The morphology, orientation relation （OR）, and habit plane of the hydrides were studied by means of transmission electron microscopy （TEM）. It was found that in the two alloys most of the precipitates are δ-hydrides which have fcc structure with the lattice parameter a = 0.44 nm. Two basic orientation relationships and habit planes of the precipitates are determined. Twin structure was observed in both alloys.     

Study of δ-hydrides in Ti-2Al-2.5Zr and Ti-4Al-2V alloys

The α alloy Ti-2Al-2.5Zr and near α alloy Ti-4Al-2V were hydrogenated to various levels. The morphology,orientation relation (OR), and habit plane of the hydrides were studied by means of transmission electron microscopy (TEM). It was found that in the two alloys most of the precipitates are δ-hydrides which have fcc structure with the lattice parameter a = 0.44 nm. Two basic orientation relationships and habit planes of the precipitates are determined. Twin structure was observed in both alloys.     

Ti-2Al-2.5Zr合金再结晶特性及动力学机制

在650℃～850℃范围内研究了单相α钛合金Ti－ZAl－2．5Zr的再结晶特性与动力学规律。结果表明：Ti－ZAl－2．5Zr合金管材在700℃～750℃下进行真空退火,可获得完全再结晶等轴组织,晶粒细小、均匀。Ti－ZAl－2．5Zr合金再结晶过程遵循Avrami-Ero－feev动力学模型,其具体方程为[－ln（1-α）]1/4=kt,温度对再结晶速率有明显影响。Ti－2Al-2．5Zr合金的再结晶活化能计算值为115．25kJ／mol。     

Characterization of micro-arc ceramic coatings on Ti-2Al-2.5Zr alloy substrates

Titanium oxide coatings were synthesized on Ti-2Al-2.5Zr alloy substrates by micro-arc oxidation （MAO） technique. The surface features of the coatings were studied by scanning electron microscopy. The micro-arc discharge channels of the Ti-2Al-2.5Zr alloy decrease while the discharge channel size increases clearly with an increase in treating time. With an increase of the coating thickness the porous layer thickness increases apparently. Phase composition of the surface layers of the coatings was evaluated by X-ray diffraction and X-ray photoelectron spectroscopy. The results of XRD and XPS analysis show that the MAO coating mainly consists of anatase and rutile TiO2.     

Diffusion bonding of Ti-2.5Al-2.5Mo-2.5Zr and Co-Cr-Mo alloys

A solid state diffusion bonding between two metallic biomaterials, Ti-2.5Al-2.5Mo-2.5Zr alloy and Co-Cr-Mo alloy (F75), has been investigated by using energy-dispersive spectrometer analysis, metallographic observation and bonding strength evaluation. The experiments indicate that bonded at 750 °C leads to insufficient atoms diffusion and weak bond. When bonded at 900 °C some intermetallics, CoTi₂, Co₂Ti, and Cr₂Ti, form in the diffusion zone, which significantly deteriorate the plasticity and lead to lower bonding strength. A high bonding strength can be achieved when bonding at 850 °C for 60 min. During the bonding process each element exhibits various diffusion velocity in the opposite alloy. The diffusion coefficients for those elements can be ranked in following sequence: D_Co > D_Cr > D_Mo in the Ti-2.5Al-2.5Mo-2.5Zr alloy and D_Ti > D_Al > D_Zr in the Co-Cr-Mo alloy.     

氢对Ti-2Al-2.5Zr钛合金疲劳性能的影响

研究了4种含量的氢对Ti-2Al-2.5Zr钛合金疲劳性能的影响。结果表明，自然含氢量的材料具有最好的疲劳性能。而当疲劳载荷大于材料的屈服强度时，氢含量对疲劳寿命基本没有影响；低于屈服强度后，疲劳寿命随着氢含量的升高而和。认为固溶的原子氢导致驻留滑移带软化，裂纹萌生提前，造成在较大△σ时充氢试样的疲劳寿命降低；而材料中氢化物对驻留滑移带（PSB）的阻碍作用导致氢化物与基体分离 而成为裂纹源，是小△σ下疲劳寿命降低扩要原因。     

Ti-2Al-2.5Zr合金N+离子注入表面XPS和XRD分析

Ti-2Al-2.5Zr合金中注入能量为75keV的N+离子, 注入剂量为3×1017/cm2和8×1017/cm2, 注入过程样品的温度低于200℃. N+离子在Ti-2Al-2.5Zr合金中的射程借助TRIM 96程序计算为1222. 注入后的样品用X射线衍射方法(XRD)以及光电子能谱方法(XPS)进行分析. XRD衍射谱表明有新相生成, 经分析为TiN和TiO2, 但这些新相的峰非常微弱, 很难区分. XPS宽程扫描谱表明注入后样品表面主要为Ti, C, N和O. XPS关于Ti2p和N1s窄程扫描谱表明N+离子注入后在合金表面确实形成了TiN和TiO2.     

Microstructural Effects on Corrosion Behavior of Investment Cast Ti-6.5Al-3.4Mo-1.7Zr Alloy

Abstract

Ti–6.5Al–3.4Mo–1.7Zr was cast as rods in a graphite mold using vacuum induction furnace. The cast rods were hot swaged then heat treated by using two regimes which resulted in fine and coarse lamella structures. The influence of these different structures on the corrosion behavior of α+β Ti-alloy samples was investigated. Potentiodynamic polarization in 3.5%NaCl solution showed that the swaged condition exhibited the highest corrosion resistance compared to the others. After isothermal oxidation for different times (2, 4, 8 and 16h), maximum weight gain was obtained after 8 h and the corrosion resistance of the swaged material was significantly higher than the other conditions. Thereby, isothermal oxidation enhanced markedly the corrosion resistance of the studied Ti-alloy. Among various conditions of the isothermally oxidized samples, the as-cast condition showed the highest value of pitting potential.     

Ti-2Al-2.5Zr单道次皮尔格轧制过程中显微组织和织构的演化

研究了单道次皮尔格轧制过程中Ti-2Al-2.5Zr材料的变形行为和织构的演变规律。结果表明,在轧制过程中,｛102｝孪晶和柱面滑移是最容易被激活的2种变形模式,｛102｝孪晶的产生使得晶粒在轴向上的位向从<100>转向<110>。并且,在不同瞬时Q值和等效应变量下,滑移和孪生导致｛0001｝极图中最大极密度点在切向上发生变化。