Ni-Al-Sn三元系在800和1000℃时的相平衡（英文）

采用电子探针显微分析和X射线衍射分析等方法研究了Ni-Al-Sn三元系在800和1000℃时的相平衡。结果表明:(1) Ni-Al-Sn三元系在800和1000℃时均未发现三元化合物;(2) Ni-Al侧存在Ni Al、Ni_3Al、Al_3Ni和Al_3Ni_2 4个化合物,800℃时,Sn在Ni Al和Ni_3Al中的固溶度分别为3.1 at%和14.7 at%,在1000℃时分别为3.0 at%和8.0 at%。而Sn在Al_3Ni和Al_3Ni_2中几乎没有固溶度;(3) Ni-Sn侧有Ni_3Sn(r)、Ni_3Sn(h)和Ni_3Sn_2(h) 3个化合物。800℃时,Al在Ni_3Sn(r)相的固溶度为4.2 at%,1000℃时,Ni_3Sn(r)相转变为Ni_3Sn(h)相,拥有5.5 at%Al的固溶度。另外,800℃时,Al在Ni_3Sn_2(h)相中的固溶度为8.4at%,1000℃时为12.1at%;(4)Ni-Al-Sn三元系Al-Sn侧为相互贯通的液相区域,Ni在Al-Sn侧的溶解度约为1 at%。     

Ni-Co-Sn三元系相平衡的实验研究

本实验通过采用电子探针显微分析和X-ray衍射分析方法实验研究了Ni-Co-Sn三元体系在700°C和1000°C时的相平衡。在这两个温度截面中均未发现三元化合物。βCo3Sn2相和Ni3Sn2（h）相形成了一个贯穿连续固溶体相。Ni-Sn侧包含Ni3Sn（l）、Ni3Sn（h）和Ni3Sn4三个化合物相,它们中Sn的固溶度是有很大区别的。700°C时,Co在Ni3Sn（l）和Ni3Sn4中的最大固溶度在分别约为6.9 at.%和25.6 at.%,在1000°C时,Co在Ni3Sn（h）中的最大固溶度约为15.5 at.%。在700℃和1000℃下,Ni-Co侧的（αCo,Ni）相为一个贯穿连续固溶体相,并且Sn在（αCo,Ni）相中的固溶度约为1 at.% ~10.5 at.%。Ni在线性化合物CoSn相中的溶解度约为15.9 at.%。     

Ni-Co-Sn三元系相平衡的实验研究（英文）

采用电子探针显微分析和X-ray衍射分析方法研究了Ni-Co-Sn三元体系在700和1000℃时的相平衡。在这两个温度截面中均未发现三元化合物。βCo_3Sn_2相和Ni_3Sn_2(h)相形成了一个贯穿连续固溶体相。Ni-Sn侧包含Ni_3Sn(l)、Ni_3Sn(h)和Ni_3Sn_4 3个化合物相,它们中Sn的固溶度是有很大区别的。700℃时,Co在Ni_3Sn(l)和Ni_3Sn_4中的最大固溶度分别约为6.9 at%和25.6 at%,在1000℃时,Co在Ni_3Sn(h)中的最大固溶度约为15.5 at%。在700和1000℃下,Ni-Co侧的(αCo, Ni)相为一个贯穿连续固溶体相,并且Sn在(αCo, Ni)相中的固溶度为1 at%～10.5 at%。Ni在线性化合物CoSn相中的溶解度约为15.9 at%。     

Co-Cu-Zn三元系相平衡的实验研究

本实验通过采用电子探针显微分析和X-ray衍射分析方法实验研究了Co-Cu-Zn三元体系在800°C和1000°C时的相平衡。在这两个等温截面中均未发现三元化合物。在800°C等温截面,Co在β-CuZn相中的固溶度为32.36%,Cu在β1-CoZn相中的固溶度为5.28%。除此之外,γ-Co5Zn21和γ-Cu5Zn8具有相同的晶体结构,因此,它们之间形成了一个贯穿连续固溶体相。1000°C的等温截面中,β-CuZn相、β1-CoZn相、γ-Co5Zn21相、γ-Cu5Zn8相都消失了。随着温度从800°C上升到1000°C,液相区域增大。     

铜基体上渗铝层的高温抗氧化性能和组织变化(英文)

以铜为基体,采用电镀镍和浆料包渗铝法,在800°C渗铝12 h制备出组织为Ni2Al3的单相渗层。采用SEM、XRD和光学显微镜,研究在1000°C下空气中氧化25~250 h,Ni2Al3渗层的高温抗氧化性能与组织转变行为。结果表明:Ni2Al3渗层在1000°C氧化250 h后,氧化增重分别为纯铜和镍镀层的1/15和1/2。氧化时间在25 h内时,渗层表面仍有Ni2Al3相;氧化50 h后,出现NiAl相;当氧化时间增加到100 h时,Ni2Al3相完全转变为NiAl相。当氧化到250 h时,渗层仍具有良好的抗高温氧化性能。     

铜表面Ni2Al3涂层高温抗氧化性能与组织转变研究

以铜为基体,采用电镀镍和浆料包渗铝法制备出Ni2Al3渗层.研究了900℃下空气中不同氧化时间,Ni2Al3渗层的高温抗氧化性能与组织转变行为.结果表明:经电镀Ni及随后800℃×12h浆料包渗铝,可在铜表面获得厚度为250μm、物相单一的致密Ni2Al3渗层.900℃氧化实验过程中,氧化时间在100h内,渗层表面X射线衍射分析中,没有Al2O3相衍射峰产生,Ni/Ni2Al3界面的Ni2Al3,相首先转变为NiAl相,并且NiAl相随时间延长而增厚;超过150h后,在渗层中Al2O3相出现衍射峰,同时Ni2 Al3相全部转变成NiAl相.在高温氧化过程中渗层无明显剥落现象,到250h时渗层仍具有良好的抗高温氧化性能,渗层表面由NiAl相和Al2O3相组成.     

三维原子探针对10Ni3MnCuAl钢中NiAl和Cu析出位置关系的研究

将析出硬化钢10Ni3MnCuAl在900℃固溶处理2 h,500℃时效处理4 h或100 h后,用三维原子探针(3DAP)研究钢中NiAl和Cu的析出位置关系。结果表明,固溶样品中Ni、Al和Cu三种元素分布均匀。500℃时效4 h的样品中发现金属间化合物NiAl和富Cu相在相同位置析出,随着时效时间增加到100 h,NiAl相和富Cu相有逐渐分离的趋势,这是因为NiAl相为体心立方的B2结构,而富Cu相此时已趋于向面心立方的ε-Cu转变。     

两种高温合金渗Al防护层的退化过程

研究了两种镍基高温合金上的渗Al层的退化过程。两种合金用两种方法施加的涂层组织相似:外层以NiAl Ni_2Al_3为母体,上面弥散着Ti(C,N)和Al_3Ti;内层由NiAl,Ni_3Al,Ti(C,N),M_(23)C_6和M_6C等相组成。渗Al层高温氧化时的退化与外层相变紧密相关,其过程如下: Ni_2Al_3 NiAl(富Al)→NiAl(富Ni)→NiAl Ni_3Al→Ni_3Al→Ni_3Al γNi_2Al_3和NiAl(富Al)相极不稳定,而NiAl(富Ni)相十分稳定。Ni_3Al沿NiAl晶界生核标志着渗层退化的开始,渗层NiAl完全变成Ni_3Al γ是退化的终了。     

Phase and Microstructure Properties of Laser Cladding NiAl Intermetallic Compound Coating at Elevated Temperature

The phase and microstructure properties of laser cladding single phase NiAl coating at elevated temperature of 800 °C were investigated by means of XRD,SEM,and HRTEM.It was found that Ni3Al phase with a fine equiaxial microstructure precipitated along NiAl grain boundaries via the solid-state diffusion of Ni atoms during heating process.NiAl and Ni3Al phases have a common<110>zone axis.The phase and microstructure evolutions of NiAl during heating process can acquire well understand the diffusion behavior of laser cladding NiAl intermetallic compound coating and provide better guidance on its production and practical use.     

Ni3Al合金蜂窝的制备及微观组织演变规律

目的 研究Ni-Al扩散偶在热扩散过程中的微观组织演变规律,提出Ni3Al合金蜂窝形成的模型.方法 采用电镀技术在易加工的Al蜂窝表面电镀一定厚度的Ni,研究热扩散温度和时间对Ni-Al扩散偶组织结构的影响.采用X射线衍射仪对Ni-Al扩散偶进行物相分析;通过扫描电镜技术对Ni-Al扩散偶截面进行形貌及能谱分析,推测微观组织演变规律.结果 热扩散温度为500℃时,随着热扩散时间的延长,Ni-Al界面处首先出现NiAl3,然后消失,最终形成以Ni2Al3为扩散层主体、NiAl和Ni3Al为过渡层的多层实心结构;热扩散温度为700、1100℃时,Ni-Al扩散偶会分别形成以Ni2Al3、NiAl为内芯,纯Ni为外壳,并以NiAl、Ni3Al薄层过渡的多层中空结构;热扩散温度为1300℃时,随着扩散时间的延长,Al相夹心层从Al、NiAl3、Ni2Al3三相混合结构依次转化为成分均一的单相Ni2Al3和NiAl结构,扩散时间继续延长,Ni层随之耗尽,Ni-Al扩散偶最终形成以γ′-Ni3Al为强化相的Ni-Al合金.结论 Ni-Al固相扩散反应过程中,随热处理温度的提升,Al原子发生了明显的外扩散.Ni-Al液固扩散反应过程中,随热处理时间的延长,Ni原子发生了明显的内扩散.在1300℃热扩散1 h的条件下,能成功制备Ni3Al基合金蜂窝壁.     

Experimental Investigation of the Phase Equilibria in the Co–V–Sn Ternary System

The phase equilibria of the Co–V–Sn ternary system at the 900 and 1000 °C sections were investigated experimentally by means of electron probe microanalysis and x-ray diffraction analysis. Seven three-phase regions were found in the isothermal section at 900 °C and six triphase regions at 1000 °C. The Heusler-type ternary compound Co₂VSn was confirmed at 900 °C in the composition ranges of 36.7–57.6 at.% Co and 11.8–20.9 at.% Sn, becoming slightly wider at the higher temperature of 1000 °C. Sn dissolves in α(Co), Co₃V, and σ-Co₂V₃ phases with low solubility. V is almost insoluble in liquid, with solubility of less than 0.5 at.%. The solubility of Co in V₃Sn phase increased with temperature, from 4.4 at.% at 900 °C to 11.6 at.% at 1000 °C.     

Phase equilibria of the Sn–Ag–Ni ternary system and interfacial reactions at the Sn–Ag/Ni joints

There are no previous phase equilibria studies of the Sn–Ag–Ni ternary system, even though the phase equilibria information is important for the electronic industry. The isothermal section of the Sn–Ag–Ni ternary system at 240 °C has been determined in this study both by experimental examination and thermodynamic calculation. Experimental results show no existence of ternary compounds in the Sn–Ag–Ni system, and all the constituent binary compounds have very limited solubilities of the ternary elements. The binary Ni₃Sn₂ phase is very stable and is in equilibrium with most of the phases, Ag₃Sn, ζ-Ag₄Sn, Ag, Ni₃Sn₄ and Ni₃Sn phases. A preliminary thermodynamic model of the ternary system is developed based on the models of the three binary constituent systems without introducing any ternary interaction parameters. This ternary thermodynamic model is used with a commercial software Pandat to calculate the Sn–Ag–Ni 240 °C isothermal section. The phase relationships determined by calculation are consistent with those determined experimentally. Besides phase equilibria determination, the interfacial reactions between the Sn–Ag alloys with Ni substrate are investigated at 240, 300 and 400 °C, respectively. It is found that the phase formations in the Sn–3.5wt%Ag/Ni couples are very similar to those in the Sn/Ni couples.     

Phase Equilibrium in the Ni-Ti-Zr System at 800 °C

The isothermal Ni-Ti-Zr phase diagram at 800 °C was constructed by means of 50 equilibrated alloys. Electron microprobe analyses were used to determine the phase compositions and phase relationships. There is one ternary phase Ni(Ti,Zr)₂ formed in the central region. Most of the Ni-Ti and Ni-Zr binary intermetallic phases show a large Zr or Ti solubility and extend to the ternary region. According to the results of DTA measurements, there are lower liquidus regions around the ternary phase due to the ternary phase reactions with the binary intermetallic phases. There is a potential region to form the bulk metallic glass.     

Ni-Ti-Ta三元体系的相平衡关系

采用X射线衍射和电子探针显微分析方法,获得Ni?Ti?Ta三元体系在1000和1200℃的全成分范围内等温截面相图.实验结果显示,Ni?Ti?Ta三元体系的1000和1200℃等温截面相图中均存在一个固溶度较小的三元化合物τ相,且通过相平衡可知,该相在1000℃的成分为(16.3～22.4)％Ta,(15.9～24.1...     

Constitutional and microstructural investigation of the pseudobinary NiAl–W system

Pseudobinary NiAl–W section in the range 0.7–1.8 at% was characterised regarding solidification microstructure and constitution. The existence of eutectic reaction was confirmed and occurs at temperature of 1664 ± 2 °C and the composition of 1.5 at% W. As-cast microstructures indicated that the NiAl–W system is an anomalous eutectic with skewed coupled zone and that the NiAl phase is a preferential phase for eutectic nucleation. Directionally solidified alloy containing 1.5 at% W exhibited entirely eutectic structure characterised by eutectic cells with the average value of 500 μm, interfibre spacing 3.5 μm, fibre diameter 300 nm, and volume fraction of the W phase 1.4%. The solubility of W in the intermetallic phase is <0.04 at% and the solubility of Ni and Al in the W phase is negligible. Crystallographic orientation between the constituent phases was established to be cube on cube. Based on the results obtained by DTA, microstructural and compositional analysis, a new isoplethal section NiAl–W of the ternary Al–Ni–W system has been proposed.     

Defect structures and ternary lattice site preference of the B2 phase in the Al–Ni–Ru system

The energies for stoichiometric and defected binary and ternary B2 phases in the Al–Ni–Ru ternary system were calculated from first-principles. The dominant compositions-conserving constitutional defect structures for NiAl and RuAl have been determined as (Al, Ni)(Ni, Va) and (Ru, Al, Va)(Al), respectively. It was observed that Ru prefers the Ni-sublattice in NiAl, while Ni has a very strong preference for the Ru-sublattice in RuAl. Furthermore, the results indicate that a miscibility gap is likely to be stable at low temperatures in the NiAl–RuAl pseudobinary system.     

Isothermal Sections of Pd-Cu-Sn System at 500 and 800 °C

The isothermal sections of the Pd-Cu-Sn system at 500 and 800 °C up to 50% Sn were constructed. Two ternary phases τ and (Pd,Cu)₃Sn of tetragonal and orthorhombic syngony respectively were discovered in the palladium-rich region. At both temperatures, solubility of tin in the FCC solid solution phase (α) has a pronounced minimum around 75-85 at.% Cu. γ-Pd_2?x Sn and η-Cu₆Sn₅ phases of Ni₂In type form a continuous (Pd,Cu)_2?x Sn phase.     

微观相场法计算Fe含量对NiAlFe三元合金中反位缺陷的影响

采用三元微观相场模型,对铝含量大于25%(原子分数,下同)与镍含量大于75%(原子分数,下同)的NiAlFe三元合金中反位缺陷NiAl、AlNi随Fe含量变化的规律进行模拟计算,其中NiAl(AlNi)表示Ni(Al)原子占据Al(Ni)格点产生的反位缺陷。结果表明:在一定温度范围内,随着Fe含量的增大,铝含量大于25%的NiAlFe合金中AlNi浓度明显上升,NiAl浓度略有上升,但小于AlNi浓度,相反在镍含量大于75%的NiAlFe合金中NiAl浓度明显上升且远大于AlNi浓度;同一温度下比较铝含量大于25%与镍含量大于75%的NiAlFe合金中反位缺陷受Fe含量影响的程度差异,发现前者的AlNi浓度比后者受Fe含量影响大,而后者的NiAl浓度比前者受Fe含量影响大。此外,反位缺陷NiAl和AlNi浓度随时间的演化规律均是逐渐由初始值降低至平衡值;温度升高促使反位缺陷演化变缓慢以及平衡时浓度增大。