Issues on Puddle Formation During Rapid Solidification of Fe–Si–B–Nb–Cu Alloy Using Planar Flow Melt Spinning Process

The present investigation deals with the processing of rapidly solidified 10?C40?mm wide, 30?C50???m thick and 10?C30?m long continuous amorphous ribbons of Fe?CSi?CB?CNb?CCu alloy using a planar flow melt spinning (PFMS) equipment. As the formation of quality amorphous ribbon depends on the melt puddle formed between the nozzle and the rotating copper wheel, the effect of different processing parameters such as nozzle wheel gap, ejection pressure etc. on the shape and stability of puddle has been studied using a high-speed imaging system and correlated with ribbon formation. Simultaneously, a two-dimensional numerical model has been developed to simulate the puddle formation during the PFMS process. The model is based on a computational fluid dynamics technique, called volume of fluid using transient heat transfer and fluid flow equations with the evolution of free boundaries. Different simulations have been performed to study the effect of process parameters on the puddle formation. The simulated results have been verified with the experimental observations considering same set of process parameters. It has been observed that the present simulations have produced exact replica of the experimental observations. Further parametric analysis as well as analysis of simulated result has been carried out to understand how the different process parameters affect the formation of quality amorphous ribbons during PFMS process.     

Structure and Properties of Ta–Si–N Coatings Produced by Pulsed Magnetron Sputtering

Russian Journal of Non-Ferrous Metals - Coatings have been deposited by pulsed magnetron sputtering (PMS) of a TaSi2 ceramic target with a diameter of 120 mm on model silicon substrates in the...     

The Structure and Properties of Precipitation-Strengthened Composites Produced From a Cast Alloy in the Al–Si–Mg System

Powder Metallurgy and Metal Ceramics - The properties of precipitation-strengthened composites produced from an aluminum alloy were studied. The composites were prepared by powder and casting...     

Microstructural and Tribological Characteristics of Al–10Cu–Fe alloy Produced by Vertical Centrifugal Casting process

In this study, an attempt has been made to produce Al–10Cu–Fe alloy by vertical centrifugal casting at speeds ranging from 800 to 2850 rpm. The microstructural features, mechanical and wear properties have been investigated. The microstructure of Al–10Cu–Fe alloy consists of equiaxed grain morphology of the primary α-phase with eutectic phases in the interdendritic regions. It has been observed that there is a variation in the grain size from the inner surface of the casting to its outer surface. The speed also has a strong influence on the grain size and subsequent mechanical properties of the alloy. The wear properties of the alloy have been evaluated at a constant sliding velocity of 1 m/s for a range of applied load and sliding distance. The variations in the wear behavior are attributed to the size and solidification morphology of the castings.     

Production of Al–Cu and Al–Cu–Si Alloys by PM Methods

Abstract

The possibilities of the production of aluminium-base copper and/or silicon alloys by conventional powder compaction and sintering methods have been studied. The effects of various lubricants, pressing, and sintering conditions on the behaviour of Al–Cu and Al–Cu–Si alloys were evaluated systematically. The role of copper and silicon additions during compaction and sintering and their advantages or disadvantages are discussed. All alloys underwent large dimensional changes (sudden swelling followed by rapid contraction) during sintering at temperatures greater than Al–Cu eutectic temperature and it is suggested that a process of particle rearrangement is largely responsible for this behaviour. The mechanical properties of the alloys were highly dependent on the sintering temperature. PM/0215     

Directional Solidification,Structure, and Mechanical Properties of a Eutectic Nb–Si Alloy with a Natural Composite Structure for GTE Blades

Directional solidification in a liquid-metal coolant and the formation of a natural composite structure in a eutectic niobium–silicon alloy are studied to produce GTE blades in ceramic molds. The microstructure and the phase composition of the alloy are analyzed in parts of variable sections. The shortand long-term strengths of the niobium–silicon composite material are measured at a temperature of 1200°C.     

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).     

Effect of Microadditional Cerium on Annealing Embrittlement of Fe－B－Si Amorphous Alloy

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Processing of Cu–Al–Ni Alloy by Spray Atomization and Deposition Process

The present work describes a new route for the preparation of Cu–Al–Ni alloy strips via spray atomization and deposition route. The route consists of atomizing liquid Cu–Al–Ni alloy with a jet of argon gas in a closed chamber, at a pressure of 1 MPa. The semi-solid Cu–Al–Ni droplets are subsequently collected on the steel substrate placed vertically below the liquid metal stream in the atomization chamber to form a three-dimensional preform. The deposit produced on the substrate contains ~?5% porosity. The microstructural details of the spray deposited Cu–Al–Ni strips explains particularly the presence of porosity, formation of splats during the flight of spray casting and the associated microstructural evolution in Cu–Al–Ni spray deposit are explained.     

Effect of Hot Rolling on Grain Refining Performance of Al–5Ti–1B Master Alloy on Hot Tearing on Al–7Si–3Cu Alloy

It has been known experimentally that TiAl₃ acts as a powerful nucleant for the solidification of aluminum from the melt; however, a full microscopic understanding is still lacking. To improve microscopic understanding, hot rolling technique has been performed to the Al–5Ti–1B alloy and the effect of shape and size of the particles on grain refinement has been studied. The effect of hot rolling of Al–5Ti–1B master alloy on its grain refining performance and hot tearing have been studied by OM, XRD, and SEM. Hot rolling improves the grain refining performance of this master alloy, which is required to reduce hot tearing in Al–7Si–3Cu alloy. The improvement in grain refining performance of Al–5Ti–1B master alloy on rolling is due to the fracture of larger TiAl₃ particles into fine particles during rolling. The presented results illustrate that the morphology of TiAl₃ particles alter from the plate-like structure in the as-cast condition Al–5Ti–1B master alloy to the blocky type after rolling due to the fragmentation of plate-like structures. The grain refining response and effect on hot tearing of Al–7Si–3Cu alloy have been studied with as-cast and rolled Al–5Ti–1B master alloys. The results display hot-rolled master alloys revealing enhanced grain refining performance and minimizing hot tear tendency of the alloy at much lower addition level as compared to as-cast master alloys.     

Structure and properties of Fe—Ni—Si—B and Co—Fe—Ni—Si—B alloys obtained by explosive compaction of amorphous powders

Hard (up to 16 GPa) amorphous-crystalline compacts of cobalt-based alloys and iron-based alloys are made by explosive compaction from powders at pressures of 12 and 15 GPa. Their magnetic properties correspond to the amorphous-crystalline state. X-ray investigations reveal pronounced segregation of the alloying elements as a result of plastic deformation due to the blast wave. The cobalt-based alloy is more resistant to crystallization during explosive compaction than is the iron-based alloy. This is consistent with data obtain in heating tests. The most amorphous phase is preserved when cobalt alloy powder with a fraction of 63–40 μm is compacted by a blast wave traveling at 4000 m/sec (pressure 12 GPa). Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1–2(405), pp. 54–61, January–February, 1999.     

Microstructure and Properties of Fe–Cr–B–Al Alloy After Heat Treatment

By means of optical microscope, scanning electron microscope, X-ray diffraction, energy dispersive spectrometer, Rockwell and Vickers hardness tester, and wear tester, the microstructure and properties of Fe–10Cr–1B–4Al alloy quenched in different temperature has been studied. The results show that the microstructure of as-cast Fe–10Cr–1B–4Al are composed of pearlite, ferrite and the eutectic borocarbide which shows a network distribution along grain boundaries. The eutectic borocarbides are composed of M₇(C, B)₃, M₂(B, C) and M₂₃(C, B)₆. As the quenching temperature increases, the network structure of eutectic borocarbide breaks, but the type of eutectic borocarbide has no obvious change, and the matrix structure changes gradually from ferrite to pearlite. As the quenching temperature increases, the macro-hardness and the matrix micro-hardness of Fe–10Cr–1B–4Al alloy increases gradually. The macro-hardness and matrix micro-hardness of alloy reach the highest value of 45.7 HRC and 388.1 HV, respectively when the quenching temperature is 1150 °C. The hardness of alloy decreases slightly when the quenching temperature is too high. While quenching at 1150 °C, the alloy has the highest wear resistance and good comprehensive properties.     

The Influence of Synthesis Conditions on the Phase Composition,Structure, and Properties of the High-Entropy Ti–Cr–Fe–Ni–Cu Alloy

Powder Metallurgy and Metal Ceramics - The influence of production conditions on the structure, phase composition, and properties of the high-entropy Ti–Cr–Fe–Ni–Cu alloy...     

Properties of Cu–Mo Materials Produced by Physical Vapor Deposition for Electrical Contacts

Powder Metallurgy and Metal Ceramics - New Cu–Mo composite materials were produced by physical vapor deposition (PVD) using an L5 electron-beam unit. They were proposed as an alternative to...     

Hereditary Effect of the Structure of the Charge on Density,Gas Content,and Processes of Solidification of an Al–Si–Cu Alloy System

Russian Journal of Non-Ferrous Metals - The effect of the structure of the initial charge density in liquid and solid states, as well as on the temperature–time parameters of the process of...     

Effect of Melt Treatment with Water Vapor on Thermal Expansion of Alloy Al – 20–40% Si

Metallurgist - The effect of melt treatment with water vapor on the microstructure and linear thermal expansion coefficient (LTEC) of Al–(20–40)% Si alloys is studied. LTEC values are...     

Formation of magnetic anisotropy in amorphous Fe–Ni–B–Si alloys

The influence of annealing at 520°C on the saturation magnetic field and coercive force of amorphous 2NSR Fe–Ni–B–Si alloys is investigated. As a result of annealing, the saturation magnetic field reaches 1000–1800 Oe. Regions of short-range order (clusters) with a direction in which the atomic pairs are ordered are thought to be formed in the alloys. The formation of the coercive force in amorphous 2NSR alloys is described.