共查询到19条相似文献,搜索用时 218 毫秒
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钛的电阻钎焊技术研究 总被引:2,自引:0,他引:2
研究了Ti-24Al-11Nb-2Si和Ti-24Al-11Nb-5Si金属间化合物合金的热轧组织与性能,结果发现:随着变形量的增加,两种合金第二相Ti5Si3变得细小且趋向于均匀分布。变形量越大,合金的室温四点弯曲程度越大,含Ti5Si3较多的Ti-24Al-11Nb-5Si合金的弯曲强度较高。两种合金的室温弯曲断口形貌均为准解理形式,两相界面结合较强。高温拉伸试验表明:随变形量的增大,Ti-24Al-11Nb-2Si合金的拉伸强度和塑性都增加。Ti-24Al-11Nb-5Si合金由于变形量较大和较高的强化相体积含量,拉伸强度明显较Ti-24Al-11Nb-2Si合金的为高,但塑性却大为降低 相似文献
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氢对锻态Ti—25Al—10Nb—3V—1Mo合金热压缩行为的影响 总被引:1,自引:0,他引:1
利用等温压缩方法研究了氢对Ti3Al基的Ti-25Al-10Nb-3V-1Mo锻态合金热变形行为的影响。在900-1000℃范围内,氢含量为0.2%的试样可使峰值流变应力比未氢化试样降低25%-31%,即相当于降低热压缩温度将近50℃。相匠试样中氢含量增加所产生的组织变化与在更高温度压缩后所产生的组织变化相当 。 相似文献
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《稀有金属材料与工程》2000,17(3):37-39
关于iAl的高温氧化问题,国内外已有广泛报道[1,2],但缺乏对氧化产物的系统分析.本文从氧化物生成热力学角度讨论了二元TiAl及三元TiAl-Cr合金氧化产物的生成趋势,旨在为TiAl氧化层构造研究提供理论基础.1TiAl氧化物的热力学计算 二元TiAl在973K以上高温氧化时,生成两种稳定的氧化物[3]:R-TiO2和α-Al2O3。由于TiO2与Al2O3的生成自由能相近[4],在原子比约为 1:1的 TiAl基合金中,将几乎同时生成两种氧化物,故不能形成单一致密的Al2O3保护层. 式中:气… 相似文献
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研究了溅射Ti-50Al-10Cr涂层在800-1000℃对TiAl金属间化合物抗高温氧化性能的影响。结果表明,TiAl合金由于形成Al2O3和TiO2的混合氧化物而表现出较差的抗高温氧化性能,而TiAlCr层由于形成粘附性了的Al2O3膜而大大提高了TiAl的恒温及循环氧化性能,经900℃1000h长时间氧化。TiAlCr涂层对TiAl合金仍能提供很好的防护,涂层和基格结合我孔洞及裂纹出现,表现 相似文献
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利用等温压缩方法研究了氢对Ti_3Al基的Ti-25Al-10Nb-3V-1Mo锻态合金热变形行为的影响。在900~1000℃范围内,氢含量为0.2%的试样可使峰值流变应力比未氢化试样降低25%~31%,即相当于降低热压缩温度将近50℃。相同温度变形的试样中氢含量增加所产生的组织变化与在更高温度压缩后所产生的组织变化相当。 相似文献
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通过XD(ExothermicDispersion)法原位反应生成Al2 O3 与Al3Ti复合增强的铝基复合材料 ,结果表明Al/TiO2 经充分混合、挤压成坯后 ,在真空炉中以一定的升温速率加热至 10 73K左右时发生剧烈的化学反应。由SEM ,XRD及能谱分析可知 :生成物Al2 O3 呈等轴颗粒状 ,Al3Ti呈棒状。主要分析了反应过程的热力学并简要说明了影响XD合成的主要因素 相似文献
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金属陶瓷材料具有高硬度、高热稳定性和高耐磨性,提高金属陶瓷材料断裂强度和断裂韧性具有重要应用意义。本文采用粉末冶金热压烧结方法制备了Al2O3+Ti(C,N)和Al2O3+WC两种金属陶瓷材料。通过单边切口梁(SENB)法和三点弯曲等力学性能测试方法探讨了热压温度对两种金属陶瓷材料的力学性能的影响,利用X射线衍射、扫描电镜(SEM)分析了物相组成和断口显微结构。实验结果表明:Al2O3+Ti(C,N)金属陶瓷随着烧结温度的升高,力学性能升高。而Al2O3+WC金属陶瓷随着烧结温度的升高,力学性能下降,在1400℃、10MPa烧结保温15min下力学性能较好。Al2O3+WC金属陶瓷900℃热压缩断裂强度比1000℃热压缩断裂强度高。 相似文献
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N.V. Kazantseva N.V. MushnikovA.G. Popov P.B. Terent’evV.P. Pilyugin 《Journal of Alloys and Compounds》2011,509(38):9307-9311
Severe plastic deformation (mechanical activation in a hydrogen atmosphere and shear under pressure) effects on the hydrogenation of two titanium aluminides Ti3Al and TiAl-type alloy (B2) have been studied. It is shown that a conventional hydrogenation of the bulk samples allows forming the hydrides with high hydrogen content and high desorption temperature: TiAl (773 K, 1.76 mass%) and Ti3Al (1043 K, 2.94 mass%). In comparison with the conventional hydrogenation, the mechanical activation in a hydrogen atmosphere at room temperature allows one to obtain the hydrides of the TiAl (B2) and Ti3Al alloys with the reduced desorption temperature: TiAl (453 K, 1.96 mass%) and Ti3Al (531 K, 2.6 mass%). The shear under pressure has been applied to the sample before hydrogenation also leads to a reduction of the desorption temperature; however, it produces the phase transformation in the Ti3Al intermetallic compounds, which lowers the observed a maximum hydrogen content. 相似文献
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研究了TiH2-45Al-0.2Si-5Nb未球磨和球磨两种粉末的放电等离子烧结组织特征以及经1000℃、100h高温氧化后的氧化性能.结果表明,未经球磨粉末的烧结组织由层片状TiAl和Ti3Al相组成,而经球磨粉末的烧结组织由细小的颗粒状TiAJ和Ti3Al相组成.球磨粉末的烧结组织氧化速度低于未球磨粉末的烧结组织,形成了连续的Al2O3和TiO2混合氧化物层,具有良好的高温抗氧化性. 相似文献
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《Intermetallics》2000,8(5-6):659-662
Microstructure and tensile properties of orthorhombic Ti–Al–Nb–Ta alloys have been studied. In order to optimize ductility and strength of the orthorhombic alloys with the nominal compositions of Ti–22Al–23Nb–3Ta and Ti–22Al–20Nb–7Ta, various thermomechanical processing steps were implemented as part of the processing route. With a special heat treatment before rolling to obtain a fine and homogeneous rolled microstructure, the rolled microstructure resulted in a good combination of high tensile yield strength and good ductility of the alloys through available solution and age treatments. The duplex microstructure with equiaxed α2/O particles and fine O phase laths in a B2 matrix, deforming in α2+B2+O phase field and treating in O+B2 phase field, possesses the highest tensile properties. The R.T. yield strength and ductility of the Ti–22Al–20Nb–7Ta alloy are 1200 MPa, and 9.8% respectively. The yield strength and ductility values of 970 MPa and 14% were also maintained at elevated temperature (650°C). 相似文献
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Hua Ding Bingzhe Bai Dingliang Wang Dan Song Caipei Zhang Jianzhong Cui Luyi Yang 《稀有金属(英文版)》2001,20(2)
Thermohydrogen processing (THP) has received much attention in recellt years. Muchwork has been done in hydrogenation and dehydrogenation of Ti and Ti alloys to modify theirmicrostructUres and improve their mechanicalproperties [l--5]. Some work has been done inTHP of Ti,AI based alloys [6M], but little workhas been reported in the effect of hydrogen onthe superplastic behavior of Ti,AI alloys. In thepresefit work, microsttucforal changes due tohydrogenation and the effect of hydrogen as… 相似文献
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通过高温渣-金平衡实验,探讨了电渣重熔用低氟渣CaF2-CaO-Al2O3-MgO-Li2O-(TiO2)中TiO2含量对Incoloy825合金中Al、Ti含量的影响。并利用FactSage7.3热力学软件分析了渣中TiO2和Al2O3的活度与渣成分的关系。研究了渣中组元对反应4[Al]+3(TiO2)=3[Ti]+2(Al2O3)的吉布斯自由能和合金中平衡Al、Ti含量的影响规律。结果表明:反应的吉布斯自由能与渣中TiO2、CaF2和MgO呈负相关,与CaO和Al2O3呈正相关;渣中TiO2含量为0%7.27%(质量分数)时,合金烧钛增铝现象逐渐减弱,TiO2含量为11.27%时,又出现烧铝增钛现象;同一温度下,随着渣中CaO和Al2O3含量增加,合金中平衡Ti含量降低,平衡Al含量升高。随着渣中TiO2含量增加,合金中平衡Ti含量升高,平衡Al含量降低。渣中CaF2和和MgO含量变化对合金中平衡Al、Ti含量影响较小。实验结果与热力学计算结果能够很好的吻合。 相似文献
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The brazing of Al2O3 to Nb was achieved by the method of transient liquid phase (TLP) bonding. Ti foil and Ni-5V alloy foil were used as interlayers for the bonding. The base materials were brazed at 1423-1573 K for 1-120 min. The results show that the shear strength of the joint first increases and then decreases with increasing holding time and brazing temperature. The joint interface microstructure and elements distribution were investigated. It can be concluded that a composite structure, in which the base metals are solid solution Nb(V) and Nb(Ti) reinforced by Ni3Ti, is formed when the brazing temperature is 1473 K and holding time 15 min, and a satisfactory joint strength can be achieved. The interaction of Ti foil and Ni-5V foil leads to the formation of liquid eutectic phase with low melting point, at the same time the combination of Ti come from the interlayer with O atoms from Al2O3 results in the bonding of Al2O3 and Nb. 相似文献