压制压力对Ni3Al金属间化合物多孔材料孔结构及抗拉强度的影响

以Ni、Al元素粉末为原料,采用粉末冶金的方法制备Ni3Al多孔金属间化合物。研究了压制压力对Ni3Al多孔金属间化合物孔结构和抗拉强度的影响。研究结果表明,随着压制压力的增大,Ni3Al多孔金属间化合物的孔隙度呈线性减小的趋势;当压制压力达到220MPa以上时,随着压制压力的增大,Ni3Al多孔金属间化合物的最大孔径和透气度减小幅度趋缓;最大孔径是决定透气度大小的主要因素;抗拉强度与压制压力之间的关系式为sb=600(0.06P-41.51)2.45。     

金属间化合物Ni3Al薄膜的制备及性能研究

采用直流磁控共溅射法,在衬底温度为450℃的SiO2基体上制备了厚度为500nm的Ni3Al薄膜,X射线衍射(XRD)和透射电子显微镜(TEM)等测试表明,薄膜为(111)取向的L12型晶体结构金属间化合物。采用纳米压痕方法测试了薄膜的力学性能,其硬度为8.00GPa,弹性模量为200GPa。为克服亚微米级薄膜氧化增重难以测量的困难,采用四探针测试金属薄膜电阻的方法,间接给出了薄膜的腐蚀性能和高温氧化程度。结果表明Ni3Al金属间化合物薄膜的氧化速率为2.28×10-13g2/(cm4.s),薄膜具有良好的高温抗氧化性能。     

激光合成Ni_3Al金属间化合物的腐蚀行为

通过激光技术合成单Ni3Al相金属间化合物,利用电化学方法及盐雾试验研究了Ni3Al金属间化合物在Na Cl溶液中的腐蚀行为特征、耐腐蚀性能及腐蚀机理。结果表明:激光合成Ni3Al金属间化合物在不同浓度的Na Cl腐蚀介质中均能形成保护性钝化膜,当Na Cl溶液浓度低于2%时,钝化膜具有良好的稳定性和耐腐蚀性能。当Na Cl溶液浓度高于3.5%时,钝化膜产生活化溶解,稳定性下降,Ni3Al金属间化合物表面形成点蚀坑,并且随腐蚀介质浓度增大,腐蚀加剧。Ni3Al金属间化合物表面点蚀坑边缘规整、腐蚀界限清晰,腐蚀机制为典型的晶内腐蚀,腐蚀过程中未形成应力腐蚀微裂纹等破坏性缺陷,具备在沿海湿热盐雾环境下使用的潜在价值。     

金属间化合物Ni3Al基合金结构焊工研究

对Ｎｉ３Ａｌ基合金结构焊接的工艺进行了研究，对焊缝显微组织及性能进行了分析，结果表明：采用合理的焊接工艺参数，用Ｎｉ８１８焊条能够实现Ｎｉ３Ａｌ工个的结构焊接。     

金属间化合物的环境脆性

环境脆性的研究在金属间化合物的发展中具有重要意义。本文综述了近年来这方面的研究进展。     

Ni3Al/HAP生物复合材料的制备及其生物相容性

为了制备N i3A l/HAP生物复合材料并评价其生物相容性,将N i3A l/HAP生物复合材料置入大白鼠臀部的肌肉中,在置入材料的第1、3、7 d等不同的时间段取出试样周围的组织进行组织学观察.结果显示,所有动物术后活动正常,进食好,毛色光亮;伤口Ⅰ期愈合,无切口感染,表皮无明显变化;光学显微镜下观察,肌肉组织细胞正常,早期为炎症反应,并逐渐减轻和消失.N i3A l/HAP生物复合材料有较好的生物相容性.     

激光熔覆制备Fe3Al金属间化合物覆层的组织结构

为了研究激光熔覆工艺条件下Fe3Al金属间化合物合金层的组织结构特点,以纯Fe3Al粉 1%Y2O3为原料在钢基体表面激光熔覆Fe3Al金属间化合物,利用扫描电镜、能谱仪、X射线衍射试验方法等对熔覆合金层、合金层与钢基体的结合界面等进行了显微组织与相结构的分析.试验获得了致密、无肉眼可见气孔、夹杂的合金层,合金层与基体间完全冶金结合,但存在裂纹现象;熔覆合金层主要由单相Fe3Al构成,覆层组织为粗大等轴状晶团,等轴状晶团由大量极细小的条状Fe3Al晶粒构成,一些相邻的条状晶粒之间具有基本一致的晶体学取向.     

钢表面TiC/Ni3Al复合涂层及其冲蚀性能

采用钨极氩弧焊熔覆技术在钢表面原位合成金属间化合物基复合涂层TiC/Ni3Al。研究了复合涂层的组织和抗冲蚀性能,探讨了涂层的形成及抗冲蚀机理。结果表明:采用钨极氩弧焊熔覆技术在钢表面制得的TiC/Ni3Al复合材料无杂质相,颗粒分布均匀;随着预置层中(Ti+C)含量的提高TiC颗粒的数量增加,材料的硬度提高;涂层与基体之间呈现良好的冶金结合,从熔合线到涂层外表面TiC颗粒的形态逐渐从细小球形转变为等轴状、树枝状;Al、Ni、Fe元素呈梯度变化,而Ti元素主要以TiC颗粒物的形式存在于涂层中。在不同冲蚀角度下复合涂层的冲蚀量均显著小于H13钢和0Cr17Ni7Al钢,表现出优异的抗冲蚀性能。     

Fe_3Al金属间化合物强韧化研究进展

Ｆｅ３Ａｌ基合金作为一种金属间化合物新型结构材料越来越引起人们的重视，极有可能在许多场合得到应用。但是Ｆｅ３Ａｌ合金室温时的低塑性和低的断裂抗力以及高于６００℃时强度的急剧下降妨碍了它的工程应用，本文主要综述近几年来Ｆｅ３Ａｌ金属间化合物机械性能方面的研究情况。     

Concentration Heterogeneity in Structure of Intermetallic Synthesized under Compression

By X-ray analysis, TEM and SEM methods the phase composition, microstructure, and deviation from stoichiometric composition were investigated for the Ni3Al intermetallic compound obtained by cast and self-propagation high-temperature synthesis under compression with followed homogenization anneal, with the Al concentration being 24.0 and 25.0 at. pct with and without B (0.5 at. pct). It was discovered that in SHS intermetallic alloys an average local deviation from stoichiometric composition is significantly more than in the cast alloy. Dependence of the local deviation from the stoichiometric composition on the distance has a zig zag nature at the level of the grain groups. Deviation from the stoichiometric composition at the boundaries of the general type is less than at the boundaries of the special type. When the intensity of boundary migrations of the general type decreases, the degree of deviation from the stoichiometric composition increases. There is correlation between the solubility of B in the     

Ductilization of Ni_3Al by Alloying with Substitutional Elements

This paper reviews recent research on ductility improvement of B-undoped Ni_3Al alloys.Ni_3Al binaryalloys with hypostoichiometric compositions show appreciable ductility at room temperature whenthe samples are prepared by recrystallization annealing after cold pressing,although the alloys withstoichiometric and hyperstoichiometric compositions remain brittle.Melt-spun ribbons withhypostoichiometric compositions contain fine anti-phase domains (APDs),while no APD can beseen in melt-spun ribbons with a hyperstoichiometric composition.The ductility inhypostoichiometric Ni_3Al alloys is associated with low ordering energy of the alloys.The addition ofternary elements,which have been classified as γ formers such as Pd,Pt,Cu,Co and Ag.improvesductility of Ni_3Al alloys.Correspondingly,the microstructure of the melt-spun ribbons consists offine APDs.The addition of γ' formers such as Si,Ti,Zr,V,Nb and Ta leads to brittle intergranular frac-ture.No APD was observed in the melt-spun ribbons of these ternary alloys.     

Dissolution Mechanism of a Zr Rich Structure in a Ni_3Al Base Alloy

In the present research,the dissolution mechanism of a Zr rich structure during annealing of a Ni 3 Al base alloy containing Cr,Mo,Zr and B,was investigated.The annealing treatments were performed up to 50 h at 900,1000 and 1100 C.The alloy used in this investigation was produced by vacuum-arc remelting technique.The results show that at the beginning of the process,a mixed interface reaction and local equilibrium(long range diffusion) mechanism controls the dissolution process.After a short time,this mechanism changes and the dissolution mechanism of the Zr rich structure changes to only long range diffusion of Zr element.According to this mechanism,the activation energy of this process is estimated to be about 143.3 kJ·mol 1.Also the phases that contribute to this structure and the transformations that occur at the final steps of solidification of this alloy were introduced.According to the results,at the final step of solidification,a peritectic type reaction occurs in the form of L+ γ’→γ+Ni 7 Zr 2 and γ-Ni 7 Zr 2 segregates from the melt.Following this transformation,γ-Ni 7 Zr 2 eutectic separates from the remaining Zr rich liquid.The solidification process will be terminated by a ternary eutectic reaction in the form of L→γ+Ni 5 Zr+Ni 7 Zr 2.     

溅射Ni_3Al微晶涂层的抗氧化性能

研究了铸态 Ni_3Al 合金及其微晶溅射涂层在1000—1100℃下等温氧化性能及1000℃下的循环氧化性能。结果表明:铸态 Ni_3Al 合金在氧化过程中形成 Al_2O_3,NiO 和 NiAl_2O_4 的复杂氧化膜;微晶 Ni_3Al涂层在氧化过程中形成α—Al_2O_3和 NiAl_2O_4尖晶石,不含 NiO,这种氧化膜的保护作用比含 NiO 的氧化膜的保护作用好,使得其氧化增重比铸态合金小约1半。此外铸态 Ni_3Al 合金在氧化过程中沿粗大晶界发生严重的内氧化,且表面氧化膜较脆易发生剥落;微晶 Ni_3Al 涂层可以消除沿晶界的内氧化,氧化膜与基体粘附良好,未发现剥落现象。微晶化大大提高了 Ni_3Al 合金的抗氧化性能。     

Recrystallization of Ni_3 Al Base Single Crystal Alloy IC6SX with Different Surface Mechanical Processes

The recrystallization behavior of Ni 3 Al base single crystal alloy IC6SX with different mechanical processes has been studied.The specimens of the alloy were treated by surface cleaning and cold working during the blades manufacture,and then heat treated in the temperature range of 800-1260℃ for 1 h to 4 h.The microstrcture of the specimens were examined by optical and scaning electron microscopy,and the room temperature tensile property,stress rupture property under the test condition of 1100℃/130 MPa,and...     

Effect of cooling rate on the 3D morphology of the proeutectic Al_3Ni intermetallic compound formed at the Al/Ni interface after solidification

Effect of cooling rate on the 3 D morphology and the growth mechanism of the proeutectic Al_3Ni intermetallic compound(IMC) that forms at the Al/Ni interface after solidification was investigated by synchrotron X-ray microtomography in combination with EBSD analysis. The proeutectic Al_3Ni phase that forms under an average cooling rate of 0.1 Ks~(-1) shows a characteristic faceted growth behavior and presents a typical 3 D morphology as partially hollow quadrangular prisms. On the contrary, that forms under an average cooling rate of 10 Ks~(-1) shows complicated dendritic morphology with asymmetrically distributed arms and faceted V-shape groove at the distal end, indicating a gradual transition of the growth behavior from non-faceted to faceted during the solidification process. These results reveal that the morphology of the proeutectic Al_3Ni is highly sensitive to the solidification condition so that fine control of the desired morphology may be achieved by carefully manipulating the cooling profile.     

Hf在Ni和Ni3Al中的扩散行为

用含Ｈｆ扣间层合金钎接或暂存液相连接单晶高温合金时，为了使Ｈｆ尽快地由焊缝区向本合金扩散，研究了Ｈｆ在基体相Ｎｉ（γ）和Ｎｉ３Ａｌ（γ）中的扩散行为，并算出扩散系娄和扩散激活性，找到了扩散九与温度，浓度的关系，为选择合适的焊接条件提供依据。     

电场激活燃烧合成( TiB2)PNi/Ni3Al/ Ni功能梯度材料

采用电场激活压力辅助合成技术(FAPAS)制备了(TiB₂)_PNi/(TiB₂)_PNi₃Al/Ni₃Al/Ni梯度材料,主要研究电场激活燃烧合成过程中电场对材料合成及层界面扩散连接的作用。分析了梯度材料各层的界面微观组织及相组成和材料的硬度分布。结果表明,采用FAPAS 技术结合机械合金化工艺制备的(TiB₂)_PNi/(TiB₂)_PNi₃Al/Ni₃Al/Ni 功能梯度材料具有快速、简便和组织均匀密实的特点。梯度材料的陶瓷复合层、Ni₃Al层和Ni板的界面区产生成分的互扩散,形成了良好的冶金结合。从Ni板到陶瓷复合层的硬度呈梯度分布。