Effect of Vacuum Hot Pressing Temperature on the Mechanical and Tribological Properties of the Fe–Cu–Ni–Sn–VN Composites

Powder Metallurgy and Metal Ceramics - The mechanical (hardness and elastic modulus) and tribological (friction force and wear rate) properties of the Fe–Cu–Ni–Sn–VN...     

Density and Dynamic Viscosity of Sn,Sn–Ag,and Sn–Ag–Cu Liquid Lead-Free Solder Alloys

Powder Metallurgy and Metal Ceramics - Traditionally, the soldering process was carried out, applying mainly lead-based solder materials. However, the prohibition against using lead (Pb) in...     

Experiments on the aging of Sn–Ag–Cu solder alloys

Abstract

The microstructural stability of the Sn–3·8%Ag–0·7%Cu solder alloy was investigated by studying microstructural changes caused by heating small samples for various times, up to 1000 h, at 150°C. The first change, evident at high magnification after heating for 1 h, occurred from the as cast lamellar plus fibrous form of the Ag₃Sn and Cu₆Sn₅ interdendritic eutectic phases to a particulate form. With further heating, coarsening of the two compound phases occurred, gradually rendering the Sn dendrite pattern less distinct. Due to the very rapid diffusion of Cu in solid Sn, the Cu₆Sn₅ phase coarsened most rapidly, growing from its originally finely divided (200 nm) size in the ternary eutectic to form many particles up to 3 m m or more in size in a time of 100 h. At that time, nearly 50% of the total Cu was contained in these particles. The Ag₃Sn phase coarsened more slowly. Approximate measurements of average particle size as a function of time suggested that coarsening occurs by Ostwald ripening, controlled by diffusion in the Sn phase.     

Microstructural Features and Mechanical and Tribological Properties of Fe–Cu–Ni–Sn Composites Precipitation-Hardened with CrB2 Additions

Powder Metallurgy and Metal Ceramics - The structural features, hardness, elastic modulus, and wear resistance of Fe–Cu–Ni–Sn composites with different CrB2 contents, produced by...     

The Effect of Precipitation Characteristics on Hardening Behavior in Cu–Cr–Sn Alloy with Sn Variation

Powder Metallurgy and Metal Ceramics - The influence of minor solute additions of Sn on hardening behavior and microstructure evolution of the Cu–Cr–Sn alloys has been investigated with...     

Sn／Cu和Sn／Ni界面反应的电流效应

最近以来，对有关集成电路的电迁移－－感应故障进行了广泛的研究，但电迁移对界面反应的影响还未涉及，在本研究中，通过分析在２００℃下，并在通电和不通电情况下处理的反应对，研究了电迁移对Ｓｎ／Ｃｕ和Ｓｎ／Ｎｉ系的影响。在Ｓｎ／Ｎｕ反应对中生成的金属间化合物是ε－（Ｃｕ３Ｓｎ）和η－（Ｃｕ６Ｓｎ５），在Ｓｎ／Ｎｉ反应对中生成的则是Ｎｉ３Ｓｎ４相。在通电和不通电时，在两种类型的反应对中生成相同的金属化合物。     

Sintering of Tungsten and Tungsten Heavy Alloys of W–Ni–Fe and W–Ni–Cu: A Review

Tungsten is a refractory metal possessing good mechanical properties of high strength, high yield point, and high resistance to creep. Therefore, tungsten and its alloys are used in many high temperature applications. Due to the high melting point, they are generally processed through powder metallurgy method. The powders are compacted using die pressing or isostatic pressing. The compacts are sintered in a sintering furnace to achieve high density, thereby, making the metal suitable for further processing. This article reviews the recent research findings of consolidating tungsten and its alloys (W–Ni–Fe and W–Ni–Cu), from preparation of powder alloys to sintering of the compact. The advances in sintering are based on the objective of achieving good densification of the metal at lower temperature and at faster rate. The use of microwave sintering and spark plasma sintering techniques resulted in significant reduction in sintering time and producing products of good mechanical properties.     

Solidification Behaviour of Ti–Cu–Fe–Co–Ni High Entropy Alloys

For the first time, we report here that the development of the novel Ti?CCu?CFe?CCo?CNi high entropy alloys (HEAs) via vacuum arc melting technique using non consumable tungsten electrode under high purity Ar atmosphere on a water-cooled copper hearth. Ti?CCu?CFe?CCo?CNi multicomponent alloys with varying Ti/Cu (x) molar ratio (x?=?1/3, 3/7, 3/5, 9/11, 1, 11/9 and 3/2) have been prepared through the tailoring of microstructure to get understanding of the phase formation and the microstructural evolution of these multicomponent HEAs. X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopic results confirm the presence of (Cu)_ss, (Co)_ss and (??-Ti)_ss dendrites with ultrafine eutectic between cubic (Cu)_ss and Laves phase (Ti₂Co type). The solidification pathways of novel alloys are critically discussed as follows. For x?=?9/11, 1, 11/9 and 3/2; firstly, (??-Ti)_ss dendrite is formed from the liquid, followed by the liquid phase separation between the cobalt-rich solid solution (Co)_ss and copper-rich solid solution (Cu)_ss and finally, the remaining liquid undergoes eutectic reaction between copper solid solution (Cu)_ss and the Laves phase (Ti₂Co Type), whereas for x?=?1/3, 3/7 and 3/5; (??-Ti)_ss dendrite is formed first from the liquid and then remaining liquid undergoes the liquid phase separation resulting two different dendrites of (Cu)_ss and (Co)_ss phases. Detailed thermodynamic calculations have been carried to rationalize the formation of stable solid solution phases of these newly developed multicomponent Ti?CCu?CFe?CCo?CNi HEAs.     

Sintering Behaviour and Mechanical Properties of Al–Cu–Mg–Si–Sn Aluminum Alloy

The present study investigates the effect of compaction pressure and sintering temperature on densification response and mechanical properties of the Al–3.8Cu–1Mg–0.8Si–0.3Sn (2712) alloy. The compacts were pressed at 200 and 400 MPa and sintered at temperatures ranging from 570–630°C in vacuum (10^?6 Torr). The objective of the present work is to obtain an optimum sintering conditions for achieving higher sintered densities and mechanical properties. The effect of sintering temperature is evaluated by measuring the sintered density, densification parameter, microstructure, phase changes and mechanical properties. While a higher sintering temperature results in densification enhancement, it also leads to microstructural coarsening. Significant improvement in mechanical properties is obtained through age-hardening of sintered alloy under various ageing conditions (T4, T6 and T8).     

Temperature–Composition Dependence of Thermodynamic Mixing Functions of Co–Cr–Cu–Fe–Ni Melts

Powder Metallurgy and Metal Ceramics - In the framework of the CALPHAD method, a thermodynamic database was developed for calculating the thermodynamic properties of liquid alloys in the...     

Physical simulation study of the dynamic recrystallization kinetics of an Ni–Cu–Al alloy

The influence of temperature and deformation on the dynamic recrystallization kinetics of an Ni–30Cu–3Al heat-resistant alloy has been studied on the basis of experiments using a torsion plastometer. The process is simulated and mathematical model is proposed for estimating the dynamically recrystallized grain sizes. Good agreement between the calculated and experimental data is achieved.     

高强耐磨Cu—Ni—Sn合金的研究

研究了多种成分的Cu-Ni-Sn-X合金350℃下时效3h的力学性能。结果表明：加入微量的Fe和Mn后,合金既有较高的强度和硬度,又有比较好的塑性。X射线衍射分析表明CuNiSn系合金时效会析出γ相和Ni3Sn相,γ相使合金的强度大大增加,但Ni3Sn相会使合金的塑性显著降低。CuNiSn系合金的强化主要来源于固溶强化、加工硬化和Spinodal析出强化。     

Glass-Forming Ability of Mg–Cu–Ni–Gd Bulk Metallic Glasses with High Strength

The glass-forming ability (GFA) of Mg–Cu–Ni–Gd alloy system was evaluated using copper mold casting. A three-dimensional composition map of Mg–Cu–Ni–Gd system with GFA over 6 mm was revealed, confirming that the Ni addition decreased the GFA of Mg–Cu–Gd system. The maximum Ni tolerance was about 6 at.% for the Mg–Cu–Ni–Gd BMGs with GFA over 6 mm. The compressive tests displayed that the Ni addition as small as 3.45 at.% could result in higher strength for the Mg–Cu–Gd BMGs. The Mg–Cu–Ni–Gd system with small Ni content can be balanced candidates for the Mg-based BMGs with both acceptable GFA and high strength.     

Wear-resistant iron-based Mn–Cu–Sn matrix for sintered diamond tools

The objective of the present work was to determine the suitability of a new iron-based Mn–Cu–Sn matrix alloy for the manufacture of diamond-impregnated tool components. A number of specimens were consolidated by the hot press route from ball-milled powders. Density, microstructural features, phase composition, bending properties and hardness were evaluated. The results revealed excellent mechanical properties, including σ_0.2?>?850?MPa in 3-point bending and HK0.5?>?300. A commercial Co-WC reference matrix alloy was also produced for comparison purposes. Diamond-impregnated specimens with different matrices were tested for wear rate on abrasive sandstone using a test rig specially designed to simulate tool application conditions. The tests that involved 3- and 2-body abrasion ranked the alloys in different orders. Statistical analysis showed that the wear rate of diamond-impregnated composites was mainly affected by diamond concentration, but statistically significant contribution of the matrix resistance to 3-body abrasion was also found.     

Cu—9Ni—6Sn合金的形变热处理工艺

Ｃｕ－９Ｎｉ－６Ｓｎ是一种具有典型时效硬化特性的合金，对该合金的形变热处理工艺及与性能的关系进行了综述。     

Cu－9Ni－6Sn合金的形变热处理工艺

Ｃｕ－９Ｎｉ－６Ｓｎ是一种具有典型时效硬化特性的合金，对该合金的形变热处理工艺及与性能的关系进行了综述     

In situ observation of moving dislocations in a Cu10Ni6Sn spinodal alloy

In situ deformation and video tape recording have been made on a single crystal of Cu10mass%Ni6mass%Sn spinodal alloy under a 200 kV transmission electron microscope. It has been revealed that a glide dislocation in a spinodally decomposed specimen takes a straight line along the low energy direction just before making substantial motion, while the non-aged alloy has exhibited the usual round bowed-out configuration. These observations have been explained by adopting line tension approximation coupled with the directional internal stress due to the spinodal decomposition.     

An investigation on Preparation and Effects of Post Heat Treatment on Electroless Nanocrystalline Ni–Sn–P Coatings

In this study, the electroless Ni–Sn–P coatings with different amounts of Sn were deposited on copper substrates to study the properties of the as-plated and heat treated coatings, especially corrosion behavior in 10 wt% sulfuric acid. Surface composition, surface morphology, and a cross-section of the coatings were studied by Energy Dispersive Spectroscopy (EDS) and field emission electron microscope (FESEM) respectively. Structure and corrosion behavior of coatings were studied by X-ray diffraction (XRD) and electrochemical tests. Results showed that increasing in Sn content and changes in Ni and P content of the coatings led to the uniform and compact surface and changes within the structure of the coating. The coating with higher Sn content had the best corrosion behavior. Post heat treatment of nanocrystalline Ni–Sn–P coating resulted in better corrosion behavior, and the optimum heat treatment temperature was 350 °C.     

Solidification of the eutectic Ga–Sn alloy

Cyclic thermal analysis is used to study the effect of overheating of the eutectic Ga–8.5 mol % Sn melt on the presolidification supercooling. It is found that, when the liquid eutectic is overheated above the eutectic temperature (T_e = 293.5 K) and is subsequently cooled, the dependence of the presolidification supercooling on the overheating temperature exhibits monotonic ascending behavior. The maximum supercooling after heating of the melt to 339 K is 26 K. The kinetic and thermodynamic parameters of eutectic solidification are calculated using the thermal analysis curves measured during melting.     

Cu75Ni9Sn2P14非晶合金热稳定性的研究

研究了Ｃｕ７５Ｎｉ９Ｓｎ２Ｐ１４合金非晶态结构的形成及其热稳定性。在连续升温的条件下,观察各温度点的晶化情况,发现在１５０℃就有晶相出现,到４００Ｃ时结晶产物均为富铜相。