The Ni3Al-Ni3Cr-Ni3Mo section of the Ni-Cr-Al-Mo system

An investigation is reported of the constitution of the 75 at % nickel section of the Ni-Cr-Al-Mo system in the temperature range 1523 to 1073 K. Alloys in the region 10 to 20 at % Al were annealed at 1523, 1273, and 1073 K, respectively, and subjected to electron microprobe analysis, X-ray diffraction, and microscopical and hardness examination. Constitutional data are presented as partial isothermal sections and as vertical sections. At 1523 K the section consists only of fields containing ,+ and , the last mentioned phase being predominant. With decreasing temperature the and + fields increase in extent. Also, the NiMo and Ni₃Mo phases were encountered in the ternary Ni-Al-Mo alloy studied. The quaternary + alloys showed small lattice mismatch values, i.e. up to 0.25%. Raft like morphologies of were found in the quaternary alloys, resulting from directional coarsening. Observations of as-cast structures are also reported.     

Intermetallic compound formation between lead-free solders (Sn) and Cu or Ni electrodes

A kinetic model based on the principle of maximum degradation rate of the total system free energy, MDR law using thermodynamic data, is proposed and successfully applied to the selection of the first intermetallic compound (IMC) phase in Cu/Sn and Ni/Sn diffusion couples. The first phases predicted with this model for Cu/Sn and Ni/Sn are Cu₆Sn₅ and Ni₃Sn₄, respectively, resulting in good agreement with experimental observations.     

The Ni3Al-Ni3Cr-Ni3Ru section of the Ni-Cr-Al-Ru system

An investigation is reported of the 75 at% nickel section of the Ni-Cr-Al-Ru system at 1523 and 1273 K. Constitutional data obtained by electron probe microanalysis, X-ray diffraction and microscopical examination are presented as partial isothermal sections. At 1523 K, the major part of the section consists of phase, while the aluminium-rich region contains a and+ region; the extent of the solid solution of chromium and ruthenium in totals ~ 4 at%. The ruthenium-rich corner of the section shows a two-phase region consisting of + ruthenium-rich solid solution. At 1273 K the,+ and + ruthenium regions increase in extent. The/ mismatch values in the equilibrated alloys studied lie in the range ~ –0.08 to –0.39%. Constitutional features of as-cast alloys are also reported.     

Interdiffusion and compound formation in the Mo/Pd/Si thin film metallization system

The process of interdiffusion and compound formation in Mo/Pd/Si thin films was studied between 250 and 750°C via sheet resistance measurements, X-ray diffraction, Rutherford backscattering spectrometry and Auger electron spectroscopy. The results indicate that thermal annealing of the Mo/Pd/Si thin film couples between 250 and 475°C lead to PdSi interaction, Pd₂Si compound formation and consequently a small increase in the sheet resistance. In contrast, exposure of the Mo/Pd/Si thin films to temperatures higher than 475°C lead to MoPd₂Si interaction in addition to PdSi interaction, MoSi₂ compound formation and a dramatic increase in the sheet resistance. The influence of interdiffusion and compound formation on the interface morphology in the Mo/Pd/Si system was studied, and the implications of these observations to a very-large-scale integration contact metallization utilizing an Mo/Pd₂Si/Si system are discussed.     

合金元素在Ni3Al金属间化合物中的作用

介绍了Ni3Al基金属间化舍物研究的现状和前景.由于Ni3Al基金属间化合物具有高熔点、低密度和良好的抗氧化性等性能,长期以来作为高温结构的候选材料而得到了广泛的关注,但是Ni3Al在室温下塑性差和高温时强度低限制了它的使用.采用合金化的方法可使Ni3Al基金属间化合物的性能得到改善,着重介绍了合金元素在Ni3Al基金属间化合物中的作用.     

Concentration Heterogeneity in Structure of Ni3Al 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 in correlation between the solubility of B in the crystalline lattice of the Ni3Al phase and the value of the deviation from the stoichiometric composition in the grains.When the B concentration in a solid solution increases,the deviation from stoichiometric composition decreases.     

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。     

Study of the diffusion reaction in the MoNi thin film system

An investigation of the phase growth kinetics and identification of the phases formed as a result of reactive diffusion in the MoNi thin film system were carried out by electrochemical anode dissolution, standard transmission electron microscopy and electron diffraction.     

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。     

Superplasticity of a Ti-24Al-14Nb-3V-0.5Mo Intermetallic Alloy

Superplastic properties and microstructural evolution of a Ti-24Al-14Nb-3V-0.5Mo (at. pct) intermetallic alloy were studied. Optimum superplastic properties were obtained for temperatures in the interval 960℃≤5 T≤5980℃. The apparent activation energy in the superplastic regime was determined and the deformation mechanism was also discussed. Based on the studies, a curve panel with three sheets sandwich structure was fabricated successfully. The microstructures corresponding to different strain in the part were also studied.     

Intermetallic compound transformation and mechanical strength of Ni–Sn transient liquid phase sinter-bonded joints in an extreme high-temperature environment

Journal of Materials Science: Materials in Electronics - In this study, the transformation of the intermetallic phase and high-temperature durability of the 30Ni–70Sn (wt%) transient liquid...     

Evolution of Ag3Sn compound formation in Ni/Sn5Ag/Cu solder joint

Ag₃Sn compound formation was observed to evolve from the Cu side to the Ni side in Ni/Sn5Ag/Cu solder joint upon reflow process. The transformation of the interfacial compound phase at the Sn5Ag/Ni interface, i.e., from Ni₃Sn₄-based compound to Cu₆Sn₅-based compound, changes the interfacial energy state, which is the main driving force for the evolution of Ag₃Sn compound formation. The evolution consequence of Ag₃Sn compound suggests that Sn5Ag/(Cu,Ni)₆Sn₅ interface is the best energy-preferential heterogeneous nucleation site for the Ag₃Sn compound phase, comparing to the Sn5Ag/Cu₆Sn₅ interface and the Sn5Ag/Ni₃Sn₄ interface. In addition, the lower Cu concentration near the Ni side is another added driving force for the heterogeneous nucleation of Ag₃Sn phase at Sn5Ag/(Cu,Ni)₆Sn₅ interface.     

Disordering of the Ni3Si intermetallic compound by mechanical milling

The ordered f c c intermetallic compound Ni₃Si was mechanically milled in a high-energy ball mill. The severe plastic deformation produced by milling induced transformations with increasing milling time as follows: ordered f c c disordered f c c nanocrystalline f c c. The structural and microstructural evolution with milling time was followed by X-ray diffraction, TEM, hardness tests, and differential scanning calorimetry (DSC). Complete disordering occurred at milling times of 2 h and kept the saturated H of the DSC peak in the range of estimated enthalpy even after 60 h milling. The structural development during milling of the f c c solid solution for Ni₃Si was presumably dominated by the formation and refinement of a dislocation cell structure into microcrystallites which eventually reached nanometre dimensions.     

Order-induced strengthening in Ni4Mo

Polycrystalline samples of Ni₄Mo have been examined at various stages of isothermal ageing at 700° C. The mechanical properties were measured on initially disordered samples at various stages of the ordering process. These properties were correlated with microstructural observations such as domain size, degree of order and fracture characteristics. The correlations are rationalised in terms of a model for the ordering process and its effect on dislocation motion.     

Mo添加对Ni3Al-TiC润湿特性的影响机制研究

采用2AP-LEITZ高温显微镜对TiC-Ni₃Al的润湿接触角进行了实验测定,着重探讨了Ni₃Al对TiC的润湿特性以及Ni₃Al中添加少量Mo的影响机制.结果表明,TiC与Ni₃Al之间具有良好的润湿性能.5wt％Mo的添加使Ni₃Al向TiC基板浸渗的深度增大,并与TiC颗粒发生固溶反应置换出部分Ti,在其周围形成一个含Mo的壳层.在这个壳层里,Ti、Mo进一步与Ni₃Al固溶,这些反应降低了液-固表面张力,导致了润湿接触角的下降,从而改善了TiC-Ni₃Al的润湿性.     

Mechanical Properties on Ni3 Al Intermetallic Compound-SiC Composite Material Generated by SHS Method

0 Introduction The Ni3 Al intermetallic compound is of great interest because of its corrosion-resistance, and high melting point. However, it is difficult to make the intermetallic compound using the ordinary method.     

Constitution of the Ni3Cr-Ni3Al-Ni3W system

Isothermal sections of the Ni-Cr-Al-W system have been investigated at 75 at % Ni and temperatures of 1523 and 1273 K, by means of phase compositional analysis, X-ray diffraction and microscopical examination. The alloys studied lay in the range 2.5 to 10 at % Cr, 12.5 to 20 at% Al, 2.5 to 6.25 at % W, The phases formed were, and the bcc solid solution based on tungsten (designated ₂). The maximum extent of the region was found to be 3 at % each of chromium and tungsten. Preferential partitioning of tungsten to occurred. Study of an Ni-10Cr-12.5Al-2.5W alloy aged at 1273 and 1073 K, after quenching from 1573 K, showed that changes in and compositions and lattice parameters occur as a function of ageing time.     

纳米Ni 颗粒对焊锡膏的界面IMC 影响

目的研究纳米Ni对SnAg0.3Cu0.7无铅焊锡膏的焊点界面IMC影响。方法采用在助焊剂中添加纳米Ni颗粒,制备出纳米Ni颗粒增强的SnAg0.3Cu0.7焊锡膏,分析纳米Ni在150℃时效中对IMC的影响。结果在150℃时效中界面IMC的厚度随着时效时间延长而增大,形貌变成平缓层状;添加Ni质量分数为0.025%时,对界面IMC几乎无影响,当添加质量分数为0.05%和0.1%的纳米Ni能促进IMC的生长,但抑制Cu3Sn层的生长。结论通过添加纳米Ni颗粒,在150℃时效中可促进IMC的生长,抑制Cu3Sn层的生长。     

Intermetallic phases in the aluminium-side corner of the AlFeSi-alloy system

Intermetallic phases formed in the aluminium-base alloys of composition 4 to 14 mass % Si and 20 to 35 mass % Fe were studied by electron probe microanalysis and X-ray diffraction. In the non-equilibrium (as-cast) samples-AlFe,-AlFeSi,-AlFeSi and-AlFeSi phases were identified. It was established that the-AlFe phase contained 1 to 6% Si causing a change of lattice parameters. In the quasi-equilibrium (heat-treated) state the chemicai composition of the-AlFeSi is within 6 to 9.5% Si and 32 to 36% Fe and that for the-AlFeSi within 14 to 16% Si and 27 to 28% Fe. On the basis of the chemical compositions of the intermetallic phases, the 600° C isotherm section of the aluminium-side corner of the AlFeSi-system was revised.